Molecular Imaging Agents & Techniques

Hall D                                   Tuesday 13:30-15:30                                                                                                                                             

13:30         3202.     A Novel Targeted Iron Oxide Nanocolloid Agent for T1 and T2* Imaging of Fibrin Using Conventional MR Techniques

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Shelton D. Caruthers1,2, Angana Senpan1, Dipanjan Pan1, Mike J. Scott1, Patrick J. Gaffney3, Christian Stehning4, Jochen Keupp4, Patrick M. Winter1, Samuel A. Wickline1, Gregory M. Lanza1

1Washington University, St. Louis, Missouri, USA; 2Philips Medical Systems, Andover, Massachusetts, USA; 3St. Thomas' Hospital, London, UK; 4Philips Research Europe, Hamburg, Germany

A novel nanocolloid contrast agent with multiple iron-oxide crystals per nanoparticle (1240 &[mu]g Fe per g of emulsion) has been targeted to fibrin clot phantoms and human endarterectomy specimens in vitro. The agent can be visualized as the typical signal dearth on T2* imaging, but also as bright signal on conventional T1-weighted turbo spin echo imaging.  The agent is constrained by size to the vasculature and is predicted to allow imaging to be performed within minutes post-injection.


14:00         3203.     19F Magnetic Resonance Imaging of Increased VCAM-1 Expression in the Kidneys of ApoE-Null Mice Using Targeted  Perfluorocarbon Nanoparticles

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Richard Southworth1, Junji Chen2, Lei Zhang2, Megan Kaneda2, Huiying Zhang2, Samuel Wickline2

1King's College London, London, UK; 2Washington University School of Medicine, St. Louis, Missouri, USA

Vascular Cell Adhesion Molecule-1 (VCAM-1) is responsible for the tethering of leukocytes to the vascular lumen in early inflammation.  It has been implicated in the pathogenesis of numerous inflammatory diseases, and therefore represents a potentially useful molecular imaging target.  We have developed unique liquid perfluorocarbon nanoparticles which can be functionalised with homing ligands in their outer lipid layer, allowing us to target them to intravascular biomarkers of disease.  These nanoparticles are capable of delivering a targeted payload of over 50,000 Gd atoms, or by virtue of their high 19F content (98% by volume), providing a quantifiable 19F MR signal. Here, we describe their use in specific visualisation and quantification of VCAM-1 expression in the kidneys of atherosclerotic ApoE-/- mice.


14:30         3204.     First Results of an Ex-Vivo Experiment on Human Plaques Using a Contrast Agent Targeting Activated Platelets

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Dominik Paul1, Constatin von zur Mühlen1, Julia Möller1, Timo Spehl1, Christoph Bode1, Karlheinz Peter2, Dominik von Elverfeldt1

1University Hospital Freiburg, Freiburg, Germany; 2Baker Heart Research Institute, Melbourne, Australia

Targeted MRI contrast agents are gaining importance in clinical diagnostic. Here we present an experimental ex-vivo environment for the evaluation of target specific MRI contrast agents on human plaque tissue. The contrast agent consists of microparticles of iron oxide and single-chain antibodies targeting ligand-induced binding sites on activated glykoprotein IIb/IIIa-receptors. Specific target binding resulted in a clear signal drop in high resolution, high field T2 and T2* imaging and was verified by immunohistochemistry. The experimental setup proves to be a promising tool for pre-clinical research on target specific contrast agents.


15:00         3205.     Towards Dual-Mode Imaging of Vulnerable Plaques [Not Available]

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Ben Jarrett1, Bjorn Gustafsson1, Angelique Louie1

1UC Davis, Davis, California , USA

We have developed dual-mode imaging agents detectable by both MRI and PET for detection and diagnosis of plaque vulnerability.  The probes are targeted to macrophages, whose density correlates with plaque vulnerability.


13:30         3206.     Characterization of Signal Ehnacement Following the  Intraperitoneal Injection of Gadolinium Based Contrast Agents

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Sharon Portnoy1, Jonathan Bishop1, Jun Dazai1, Shoshana Spring1, R.M. Henkelman1,2

1Toronto Centre for Phenogenomics, Toronto, Canada; 2University of Toronto, Toronto, Canada

The objective of this investigation is to determine the enhancement time-course and dosage requirements in mice for intraperitoneally (IP) administered Gadolinium contrast agents.  Although higher doses are required (~2.5 mmol/kg) and enhancement is slightly delayed, results suggest that IP injection may be an effective method for Gadolinium administration.  The relative simplicity of IP contrast administration compared to traditional tail-vein injection makes this method a convenient alternative, particularly in longitudinal studies and high-throughput imaging of large numbers of mice.


14:00         3207.     Fluorine-19 MRI of the Lung: First Human Experiment

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Ursula Wolf1, Alexander Scholz1, Maxim Terekhov1, Kerstin Muennemann1, Karl Kreitner1, Christian Werner1, Christoph Dueber1, Wolfgang Guenter Schreiber1

1Johannes Gutenberg University, Mainz, Germany

As fluorine-19 MRI of the lung appears to be a promising tool for the diagnosis of obstructive lung diseases such as COPD, efforts have been made to improve image quality and to develop a technique which can be safely and effectively used in humans. Since 1984, a lot of animal experiments have been performed using SF6, C2F6, C4F8, C3HF7, and CF4 as contrast gases. Here, we present the data of the first human experiment using up to 78% SF6. This experiment is an important milestone towards the use of fluorine-19 MRI in patients.



14:30         3208.     In-Vivo Ultra-High Resolution Imaging of Small Vessels Using Improved Sensitivity and Long Circulation Time of FeCo-Graphitic Carbon Shell Nanocrystals

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Jin Hyung Lee1, Sarah Sherlock1, Masahiro Terashima1, Hisanori Kosuge1, Won Seok Seo1,2, Yoriyasu Suzuki1, Michael V. McConnell1, Dwight G. Nishimura1, Hongjie Dai1

1Stanford University, Stanford, California , USA; 2Sogang University, Seoul, Republic of Korea

FeCo-Graphitic Carbon Shell Nanocrystals have been recently reported to have an unprecedented high relaxivity with multi-functional capabilities. In this paper, we demonstrate how the improved sensitivity provided by the high relaxivitiy combined with the long circulation time can be used to generate high-resolution in-vivo vessel images.


15:00         3209.     Development of a New Series of Nitroimidazoles Probes for Oxygen Tension (pO8) Measurement by 1H Magnetic Resonance Spectroscopy

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Jesus Pacheco1,2, Paloma Ballesteros2, Sebastian Cerdan1, Pilar Lopez-Larrubia1

1Instituto de Investigaciones Biomedicas "Alberto Sols"- CSIC, Madrid, Spain; 2Instituto Universitario de Investigacion - UNED, Madrid, Spain

Hypoxia is known to be an important physiological parameter determining tumour progression and malignancy. In this study, we report the synthesis and in vitro evaluation of a new series of nitroimidazolyl derivatives as quantitative pO8 markers. The NADPH:cytochrome P450 reductase enzymatic systems was found to reduced the probes only under anoxic conditions. Incubation of one of this derivative with C6 cells under different oxygen concentrations depicted clearly visible changes in the 1H-NMR spectrum at the probe, which depended on the degree of hypoxia.


13:30         3210.     Targeted MR Imaging of CD44-Positive Breast Cancer Stem-Like Cell Phenotype

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Dmitri Artemov1, Wenlian Zhu1, Yoshinori Kato1, Marie-France Penet1, Farhad Vesuna1, Zaver Bhujwalla1, Venu Raman1

1Johns Hopkins University, Baltimore, Maryland, USA

Recently, a subpopulation of highly tumorigenic and drug resistant cancer cells was identified in multiple solid tumors, which is currently referred to as cancer stem-like cells.  In breast cancer, these cells are characterized by high level expression of the cell surface receptor CD44 and decreased expression of another marker, CD24..  Here we have developed a CD44-targeted system for MR imaging of breast cancer stem-like cells and demonstrated the MR imaging of CD44 positive MDA-MB-231 human breast cancer cell in vitro.


14:00         3211.     Nanoglobular Gd-DO3A Conjugates as Highly Effective MRI Contrast Agents

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Todd Kaneshiro1, Eun-Kee Jeong, Dennis Parker, Zheng-Rong Lu1

1University of Utah, Salt Lake City, Utah, USA

Novel macromolecular Gd(III) chelates with well-defined nanosizes and globular morphology were synthesized as highly effective MRI contrast agents.  The nanoglobular MRI contrast agents resulted in significant blood and tumor enhancement at a substantially reduced dose, e.g. 10 µmol-Gd/kg.


14:30         3212.     Manganese-Alginate Gels for Controlled-Release of Mn2+

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Christian Brekken1, Ioanna Sandvig1, Olav Haraldseth1, Gudmund Skjåk-Bræk1, Yrr Mørch1

1NTNU, Trondheim, Norway

In the present study we aimed at designing alginate beads for controlled release of Mn2+. Both elemental analysis and swelling studies of the alginate gel beads showed great differences in the ion binding properties of alginate to manganese. Dynamic T1-weighted MRI of single alginate beads immersed into NaCl-solution showed that the Mn2+ release rate differed by a factor of up to ~100% between the 4 differently designed beads imaged. The results indicate that nano-fabrication of Mn-alginates can tailor-make biocompatible manganese delivery systems and hopefully help in introducing MEMRI in targeted contrast-enhanced MRI of otherwise toxicity-limited organs, such as the brain.


15:00         3213.     Novel Receptor-Targeted Nanoparticles for MR Imaging and Specific Delivery of Gene Therapy

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Panagiotis Kyrtatos*1, Michele Writer*, Anthony N. Price1, Stephen Hart, Mark F. Lythgoe1

1Institute of Child Health and Department of Medicine, University College London, London, UK

Multimodal nanoparticles offer a promising application as MRI contrast agents with therapeutic capabilities. Our group is developing a novel gene therapy vector, which utilises an anti-cancer targeting peptide for specific transfection of tumour cells with therapeutic genes. In addition, a Gd3+ moiety has been incorporated for non-invasive real-time monitoring of the delivery. Here we present a pilot in-vitro tumour cell study investigating the MRI properties of the vector, confirming its potential for both specificity of delivery of DNA to the target cells for gene therapy and also providing evidence of the MR contrast enhancement in targeted cells.


13:30         3214.     MR Imaging of Breast Cancer Using the Folate-Receptor Targeted Contrast Agent P1133

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Reinhard Meier1,2, Tobias D. Henning1, Sophie Boddington1, Sidhartha Tavri1, Sandeep Arora1, Claire Corot3, Ernst J. Rummeny2, Heike E. Daldrup-Link1

1University of California San Francisco, San Francisco, California , USA; 2Technical University Munich, Klinikum Rechts der Isar, Munich, Germany; 3Guerbet, Paris, France

The purpose of this study was to assess the uptake of the new FR-targeted USPIO P1133 in breast cancers. In vivo studies demonstrated a progressive enhancement of central tumor areas with the FR-targeted USPIO P1133 in FR-positive MDA-MB-231 breast cancers. Corresponding SNR data were significantly higher for P1133 compared to P904B, indicating at least a component of FR-specific enhancement with P1133. The P1133 tumor uptake was not significantly inhibited by FFA in vivo, most likely due to the rapid FFA metabolism in the liver. Thus, the FR-targeted USPIO P1133 provides a significant and specific enhancement of FR-positive MDA-MB-231 breast cancers.


14:00         3215.     Synthesis and Characterization of a Redox- And Light-Responsive MRI Probe [Not Available]

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Chuqiao (Tom) Tu1, Ryan Ngao1, Angelique Louie1

1UC Davis, Davis, California , USA

We have previously developed a gadolinium contrast agent that reversibly changes relaxivity properties in response to irradiation by different wavelengths of light.  We here demonstrate that the contrast agent can also be modulated by reduction/oxidation.  The mechanism for the relaxivity effects in response to redox appear to differ from the light induced response.


14:30         3216.     Quantitative Molecular Imaging with a Combined Fluorescence Diffuse Optical Tomography and MRI System

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yuting lin1, Orhan Nalcioglu2, Gultekin Gulsen2

1University of California, Irvine, California , USA; 2University of California, Irvine, California , USA

An ideal molecular imaging technique should have both high sensitivity for molecular probes and also provide high-resolution images. Our solution to this demanding requirement is to employ a multimodality imaging strategy. In this study, we show the feasibility of using a combined MRI and optical fluorescence imaging approach to quantitatively resolve the fluorescence contrast agent concentration. The true fluorophore concentration was recovered only if the MRI anatomical information was employed.


15:00         3217.     Real-Time Feedback Paradigm for Functional and Metabolic Imaging Using a Combined PET/MR Scanner: Proof of Concept

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Thomas Sheung Chee Ng1,2, Daniel Procissi1, Andrey Demyanenko1, Yibao Wu3, Ciprian Catana4, Simon R. Cherry3, Andrew A. Raubitschek5, Russell E. Jacobs1

1California Institute of Technology, Pasadena, California, USA; 2University of Southern California, Los Angeles, California , USA; 3University of California,  Davis, Davis, California , USA; 4Massachusetts Gener

Positron Emission Tomography (PET) and Magnetic Resonance (MR) offer complementary functional and anatomic information that provide unique windows into biological processes. As well as integrating images in space and time, the combined PET/MR scanner offers the potential to perform real time analysis of multi-modal data that can feedback to direct further studies in a single imaging session. We demonstrate the feasibility of this paradigm. Mice implanted with tumor cells were imaged simultaneously with PET/MR. Functional data derived from the PET was used as a basis for 1H-MR spectroscopy studies, demonstrating metabolic heterogeneity within a tumor cell mass.


MRS of Cells, Body Fluids

Hall D                                   Wednesday 13:30-15:30                                                                                                                                       

13:30         3218.     [3-13C]Pyruvate: Useful Alternative to Labeled Glucose for in Vitro Metabolic Studies in Primary Mouse Hepatocytes

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Sven Gottschalk1, Michaela Hohnholt2, Dieter Leibfritz2, Marc Bilodeau1, Claudia Zwingmann1

1University of Montréal, Montréal, Canada; 2University of Bremen, Bremen, Germany

Application of stable isotope labeling in vitro is a powerful method to study metabolic pathways and fluxes. We applied [3-13C]pyruvate on primary mouse hepatocyte cultures to establish labeled pyruvate for metabolic studies and flux analysis in this cellular model. Our results show: [3-13C]pyruvate was metabolized by lactate dehydrogenase, alanine-/aspartate-aminotransferase, PC, PDH and subsequent metabolic pathways through the TCA-cycle. Considering that almost no 13C-NMR studies in isolated hepatocytes have been performed so far, labeled pyruvate will provide an important physiological substrate to assess hepatocellular pathways and the de novo synthesis of metabolites in these cells under normal and pathological conditions.


14:00         3219.     A Versatile NMR-Compatible Bioreactor for Alginate-Encapsulated Liver Cells

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Rex Errol Jeffries1, Kayvan R. Keshari, Chris Seagle, Peter Pediaditakis, Michael P. Gamcsik, John Kurhanewicz, Jeffrey M. Macdonald

1University of North Carolina, Chapel Hill, USA

Synopsis: A remodeled NMR-compatible bioreactor was used with electrostatic alginate encapsulation of hepatocytes to create a bioartificial liver ultimately designed for metabolomic studies. The 500 μm diameter spherical encapsulates are well perfused and permit the use of 20% oxygen rather than the standard 95% oxygen. The 31P NMR spectra from a rat liver cell line, JM1, and primary rat hepatocytes were compared to oxygen uptake rates for bioenergetics.


14:30         3220.     Metabolism of Colonic Mucosa in Patients with Ulcerative Colitis (UC) and Crohn’s Disease (CD): An NMR Study

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B Krithika1, S Kumar1, R R. Singh1, Uma Sharma1, V Ahuja1, G K. Makharia1, N R. Jagannathan1

1All India Institute of Medical Sciences, New Delhi, India

In vitro NMR spectroscopy demonstrated significant differences in the concentration of amino acids (isoleucine/leucine/valine, glutamic acid + glutamine, alanine), membrane components (choline, glycerophosphorylcholine, myoinositol), glycolytic product (lactate) in patients with active state of ulcerative colitis (UC) and Crohn’s disease (CD) compared to controls indicating a decreased protein and carbohydrate metabolism.  In the remission state, levels of most of the metabolites were similar to controls. A significant difference in the concentration of formate was observed between patients with active states of UC and CD suggesting its potential as a biomarker for distinguishing UC and CD.


15:00         3221.     Cellular Metabolism and Apoptosis – Dexamethasone, a Promising New Candidate to Intervene on the Metabolic Level

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Sven Gottschalk1, Michaela Hohnholt2, Dieter Leibfritz2, Claudia Zwingmann1, Marc Bilodeau1

1University of Montréal, Montréal, Canada; 2University of Bremen, Bremen, Germany

We have recently shown that the initial phase of the apoptotic process is associated with alterations in specific glucose metabolic pathways. The synthetic glucocorticoid Dexamethasone is known for its anti-apoptotic effects and impact on glucose metabolism (in particular, anaplerosis and gluconeogenesis). We therefore characterized the effects of Dexamethasone on hepatocellular metabolism with multinuclear NMR-measurements. Our results further support the strong relationship noted between changes in cellular metabolism and apoptosis. This paves the way toward the therapeutic modulation of cell metabolism in order to influence upon cell survival/death particularly in the context of liver injury.


Cell Labelling & Tracking

Hall D                                   Wednesday 13:30-15:30                                                                                                                                       

13:30         3222.     In Vivo Imaging of Endogenous Neural Stem Cells Labelled with a Ferumoxide-Polycation Complex Using a Low Field System

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Rachael Dobson1,2, Patrizia Ferretti1, Mark Lythgoe1

1University College London, London, UK

Adult neural stem cells (NSC) migrate towards the olfactory bulb and differentiate into neurons. Ferumoxide-based contrast agents have been used to track the migration of exogenously-labelled NSC, there are limited methods that allow for longitudinal tracing of endogenous neural stem cells using MRI. In this study, two MRI contrast agents were used to label the endogenous population of NSC and neuroblasts in situ in the subventricular zone.  Cell labelling and T2* contrast were assessed up to 28 days post-labelling using a low-field system.  Cell migration was observed in vivo and ex vivo, and histology confirmed labelling of migrating neuroblasts.


14:00         3223.     Quantification of Cell Trafficking in Vivo Using Magnetically Sensitive Histograms

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Christopher M. Long1, Hyam I. Levitsky1, Jeff W.M. Bulte

1Johns Hopkins University School of Medicine, Baltimore, Maryland, USA

Quantification of dendritic cell migration to lymph nodes in vivo is critical for evaluating the efficacy of tumor vaccines.  We developed a new method based on magnetically sensitive histograms and cell-cell transfer of SPIO particles in vivo.   It was found to correlate exceptionally well with ex vivo cell counts after magnetically activated cell sorting  The method may be used to monitor the biological variability associated with cancer vaccination and to evaluate the efficacy of immunoadjuvants.


14:30         3224.     In Vivo Stem Cell Tracking Using Magnetic Resonance Imaging in the Rat Genitalia of a Radical Prostatectomy Model
[Not Available]

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Young Taik Oh1, Jang Hwan Kim1, Yong-Min Huh1, Myeong-Jin Kim1, Jin-Suck Suh1

1Yonsei University College of Medicine, Seoul, Republic of Korea

Erectile dysfunction is a major complication after radical prostatectomy for prostate cancer. There have been vigorous trials for improving erectile dysfunction but no satisfying method until now. Previous reports have shown that stem cell injection improved erectile function in a rat model erection dysfunction. However, they used the immunohistochemical stain for the evaluation of stem cell. A reliable in vivo imaging method to localize transplanted cells and monitor their restorative effects will enable a systematic investigation of cell therapy. Our results showed that in vivo stem cell tracking using MR imaging in a rat model of radical prostatectomy was feasible.


15:00         3225.     Comparison of Different Iron-Oxide Agent Detection Methods Using a Single Dataset

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Gopal Varma1, Richard Tavare1, Hannes Dahnke2, Stephen Keevil1, Tobias Schaeffter1

1King's College London, London, UK; 2Philips Research Laboratories, Hamburg, Germany

Detection of super-paramagnetic iron oxide can be achieved at varying sensitivities through its inherent negative contrast or by positive contrast methods. A single multi-echo dataset is used to compare T8* weighted imaging, R8* mapping, and positive contrast methods. In our study this includes inversion recovery on-resonance (IRON), gradient dephasing (“white marker”), and susceptibility gradient mapping (SGM). T8* images are found to be most sensitive to the smaller concentrations at short echo times (TEs), but high sensitivity of SGM and T8* imaging suggests a combination of these two methods is ideal. Data acquired for T8* images and SGM at 2 different TEs to address different concentrations would provide a more sensitive differentiation to the background.


13:30         3226.     Stem Cell Treatment for Peripheral Arterial Disease - Comparison of Plain and Encapsulated X-Ray Visible Mesenchymal Stem Cell Transplants

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Dorota A. Kedziorek1, Wesley D. Gilson2, Kenyatta Cosby1, Matthias Stuber1, Bradley P. Barnett1, Royston C. Boston3, Grigorios Korosoglou4, Bernard E. Kohl1, Gary Huang1, Brady Sieber1, Aravind Arepally1, Jeff W.M. Bulte1, Lawrence V. Hofmann5, Dara L. Kraitchman1

1Johns Hopkins University, Baltimore, USA; 2Siemens, Baltimore, USA; 3University of Pennsylvania, Kennet Square, USA; 4University of Heidelberg, Heildelberg, Germany; 5Stanford University, USA

The resented work comapares plain and encapsulated Mesenchymal Stem Cell therapy in Peripheral Arterial Disease model. Non-invasive imaging demonstrated a more robust angiogenic response with encapsulated MSCs, while "naked" MSCs can incorporate into the vessel walls.


14:00         3227.     Micrometer-Sized Particles of Iron Oxide (MPIOs) Enhanced Cardiac Imaging to Potentially Monitor Inflammatory Cells Infiltration in a Murine Model of Myocardial Infarction

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Yidong Yang1,2, Ben Waghorn1,2, Yuhui Yang1, Brianna Klein1, Nathan Yanasak1, Tom C-C. Hu1,2

1Medical College of Georgia, Augusta, Georgia, USA; 2Georgia Institute of Technology, Atlanta, Georgia, USA

Inflammatory process plays an important role in myocardial injury and the subsequent recovery. In this study, we examined cell mobilization due to myocardial infarction post injection of micrometer-sized particles of iron oxide (MPIOs). MRI was performed to potentially visualize the migration and trafficking of inflammatory cells as well as to provide quantitative information. This technique indicates potential to track disease progression in a preclinical model of myocardial injury.


14:30         3228.     In Vitro MR Thermometry on Magnetically Heated Iron Oxide Labeled Stem Cells

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Daniel Haddad1, Jochen Lorenscheit2, Markus Hildenbrand1, Meike Weber2, Regina Ebert2, Peter Michael Jakob1,2

1MRB Research Center Magnetic-Resonance-Bavaria, Würzburg, Germany; 2University of Würzburg, Germany

Iron-oxide nanoparticles are commonly used as MR markers to label and track (stem) cells. Magnetic particle heating (magnetic field hyperthermia) can be used to heat the iron-oxide particles and thus the iron labeled stem cells. A proof-of-principle in vitro study shows that MR thermometry can be used to visualize the spatial and temporal heat distribution with high accuracy in the vicinity of iron-oxide labeled stem cells that were heated outside the MR spectrometer via magnetic particle heating. Since the heating capacity depends on the composition and structure of the material of interest, different types of iron-oxide particles yield different heating rates. The heating rates can also be controlled by varying the amount of iron-oxide incorporated in the cells.


15:00         3229.     Tracking of Spio Labeled Natural Killer Cells to Epcam Positive Prostate Cancer with Mr Imaging

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Reinhard Meier1,2, Sidhartha Tavri1, Tobias D. Henning1, Winfried S. Wels3, Rick Baehner1, Ernst J. Rummeny2, Heike E. Daldrup-Link1

1University of California San Francisco, San Francisco, California , USA; 2Technical University Munich, Klinikum Rechts der Isar, Munich, Germany; 3Chemotherapeutisches Forschungsinstitut, Frankfurt, Germany

Development and optimization of a technique for labeling of human natural killer (NK) NK-92 cells and genetically engineered NK-92-scFv(MOC31)-zeta cells, targeted to the Ep-CAM (epithelial cell adhesion molecule) on prostate cancer cells, with superparamagnetic iron oxides (SPIO). SPIO labeled NK cells were injected intravenously into rats with implanted Ep-CAM positive prostate cancers and the accumulation of the SPIO labeled NK cells in prostate tumors could be monitored with a non-invasive magnetic resonance (MR) imaging technique.


13:30         3230.     Study on the Magnetic Relaxation of Superparamagnetic Nanotubes as Magnetic Resonance Imaging Contrast Agent

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xia Bai1, sang jun Son1,2, shixiong Zhang1, wei Liu3, elaine k. Jordan4, joseph a. Frank4, Thirumalai Venkatesan1, Sang Bok Lee1

1university of maryland college park, college park, Maryland, USA; 2Kyungwon University, Republic of Korea; 3Philips Research North America, Briarcliff Manor, New York, USA; 4National Institutes of Health, Bethe

This work describes the synthesis of magnetic nanotubes (MNTs) which is silica nanotube (SNT)/magnetic iron oxide nanoparticle (MION) composite with MIONs loaded in SNTs. This unique structure combines the easy chemistry for differential functionalization of the inner and outer surfaces of SNTs with the superparamagnetic characteristics of MIONs. The MNTs had well-controlled dimensions and retained a high saturation magnetization. It was proved that MNTs worked as an effective T2 magnetic resonance (MR) contrasting agent. The in vitro cell labeling was effective without showing significant cytotoxicity. Our results indicate that MNTs could be an ideal candidate for image-guided drug delivery.


14:00         3231.     MRI Detection of the Migrating Neuronal Precursors in Normal and Hypoxic-Ischemic Neonatal Rat Brain by in Vivo Cell Label with MPIO

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Jian Yang1,2, Jian Xin Liu3, Gang Niu2, Yong Liu3, Ed X. Wu4

1Department of Electrical and Electronic Engineering, The University of Hong Kong , Hong Kong, People's Republic of China; 2The First Hospital of Xi'an Jiaotong University, Xi'an, People's Republic of China; 3The School of

In this study,10-day-old normal rats (n=6) and hypoxic-ischemic (H-I) neonatal rats (n=6) were injected with the micronsized iron oxide particles (MPIOs) into the anterior lateral ventricle. 2D and 3D gradient echo MRI was performed with a 7T animal scanner in hour 3, day 3, day 7 and day 14 after the MPIOs injection. Then animals were sacrificed for double staining with iron and mature neurons. In normal neonatal rat brain, the migrating pathway of the endogenous neural progenitor cells (NPCs) with MPIO is mainly along the rostral migratory stream to the olfactory bulb. In H-I neonatal rat brain, the migration of endogenous NPCs with MPIO is mainly toward injured boundary. MRI can facilely detect the above migrations in 2 weeks. Therefore, in vivo magnetic cell labeling of endogenous NPCs with MPIO and subsequently non-invasive, serial MRI monitoring should open up a new approach to probe into the mechanism of cell migration in the developmental brain under physiological and pathologic states.



14:30         3232.     Quantitative Assessment of Magnetically Labeled Luciferase Positive Cells Using Multimodality Imaging

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April M. Chow1,2, Kwan Man1, Jerry S. Cheung1, Tracy Y. Chow1, Ed X. Wu1

1The University of Hong Kong, Pokfulam, Hong Kong

Cellular imaging using magnetically labeled luciferase positive cells with multimodality imaging has found numerous biological applications. However, studies only involve imaging dual-labeled cells, tracking their migrations without quantification of local density of the dual-labeled cells. Quantitative analysis of cells after transplantation may allow more accurate assessment of cell delivery and subsequent distribution and migration, which can lead to more effective monitoring and optimization of therapeutic paradigms. In this study, we demonstrated that dual-labeled cells exhibited excellent linear correlations between cell concentration with photon flux and &[Delta]R2* in vitro, illustrating that quantitative assessment of dual-labeled cells can be achieved.


15:00         3233.     Comparison of 2 Different Tumor Cell Labeling Techniques for in Vitro MRI Characterization with New Iron Oxide Particles

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Olaf Saborowski1, Francesco Santini2, Melpomeni Fani3, Philippe Robert4, Sebastien Ballet4, Jean Sebastien Raynaud4, Robin Santus4, Johannes Froehlich3, Klaus Scheffler2, Georg Bongartz3, Helmut R. Maecke3

1University Hospital Basel, Basel , Switzerland; 2University Basel/University Hospital, Basel, Switzerland; 3University Hospital Basel, Basel, Switzerland; 4Guerbet Group, Aulnay-Sous-Bois, France

Iron oxide particles (SPIO and USPIO) are widely used for MRI-based cell labeling and tracking because they can be loaded on cells by simple protocols and provide high image contrast due to their large susceptibility effect. We compared 2 different cell labeling models (AGAR and Ficoll) in human KB cells. Both presented cell labeling methods (AGAR and Ficoll model) are feasible for in vitro MR characterization of KB tumor cells at 1.5, 2.35 and 3T. Ficoll method is easier to perform because it does not need a heating procedure for preparation without air bubbles as compared to AGAR method.


13:30         3234.     Longitudinal Tracking and Quantification of T Cells Using in Vivo 19F MRI [Not Available]

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Mangala Srinivas1, Michael S. Turner2, Penelope A. Morel2, Jelena M. Janjic1, David H. Laidlaw3, Eric T. Ahrens1,4

1Carnegie Mellon University, Pittsburgh, Pennsylvania, USA; 2University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA; 3Brown University, Providence, USA; 4Pittsburgh NMR Center for Biological

19F MRI was used to track T cells in a murine model of acute inflammation for up to 21 days. Quantification of total 19F signal in the DLN, and hence apparent cell numbers, from the in vivo data showed 2.1x106 ± 9x105 apparent cells at day 2 and 3.6x106 ± 9x105 at day 7 post-transfer in the draining lymph node. The murine inflammation model can be applied to study the effect of therapeutics on T cell trafficking. The in vivo 19F platform developed can readily be extended to other cells types including, immunotherapeutics or stem cells.


14:00         3235.     A Novel Bimodal Fluorescent and Paramagnetic Lipid for Cell Labelling and Tumour Magnetic Resonance Imaging

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Nazila Kamaly1, Tammy Louise Kalber1, Jimmy D. Bell1, Michael R. Jorgensen1, Andrew David Miller1

1Imperial College London, London, UK

A novel bimodal fluorescent and paramagnetic lipid, Gd.DOTA.Rhoda.DSA was synthesised. Cationic and neutral PEGylated bimodal liposomes were formulated for cell labelling and tumour imaging respectively. Effective IGROV-1 (human ovarian carcinoma) cell labelling was demonstrated in vitro post incubation of cells with the cationic liposome formulations containing Gd.DOTA.Rhoda.DSA. The enhanced permeation and retention (EPR) effect of tumour tissue was exploited post-injection of the neutral PEGylated liposomes in mice to image IGROV-1 xenografts. Tumour T1 values were reduced 14-24 h post-injection of the bimodal liposomes by a substantial 65%. These MRI findings were supported by fluorescence findings co-validating the presence of the bimodal liposomes/lipid within tumour tissue.


14:30         3236.     Bimodal Intracellular Nanoparticles Based on Quantum Dot Technology for High Field MR Microscopy at 21.1 T

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Jens Thorvald Rosenberg1,2, Joshua M. Kogot1, Goeffery F. Strouse1, Samuel Colles Grant1

1The Florida State University, Tallahassee, USA

A bimodal contrast agent for the intracellular transfection of mammalian cells has been optimized for high magnetic field MR imaging at 21.1 T. With a fluorescent InP/ZnS quantum dot as a substrate, a peptide-bound lanthanide (Dy3+) component has been added to generate MR contrast. The CAAKA–DOTA-Ln3+-Qdot agent displays strong MR contrast enhancement for all relaxation mechanisms, but the strongest contrast for intracellular loading is seen with T2/T2* weighting. Utilizing this agent, Chinese Hamster Ovary (CHO) cells were transfected, with MR and confocal images displaying contrast enhancement and the intracellular localization of nanoparticles.


15:00         3237.     19F NMR Molecular Imaging: Cell Labeling With Emulsified Perfluoro-15-Crown-5-Ether

Computer 29

Samir Mulla-Osman1, Henrike Goetze2, Ute Bommerich3, Johannes Bernarding

1University of Magdeburg, Magdeburg, Germany; 2University of Magdeburg, Germany; 3Leibniz Institute for Neurobiology, Germany

Monitoring 19F-labelled cells is an important new technique to evaluate in vivo the fate of implanted cells such as in stem cell therapy. The use of 19F-marker substances such as perfluorocarbons (PFC) has been explored by 19F spectroscopy and magnetic resonance imaging (MRI) for cell tracking. We present first results of single volume selective spectroscopy of fibroblasts, which have been labeled with perfluoro-15crown-5-ether (PFCE) emulsion.


MRS Methodology

Hall D                                   Thursday 13:30-15:30                                                                                                                                           

13:30         3238.     MEGA-Editing of  Spermine/Spermidine in Healthy Human Prostates Using External Phased-Array Coil Assembly

Computer 25

Michael Albert Thomas1, S.Sendhil Velan2, Saadalah Ramadan3,4, Nagarajan Rajakumar1, Daniel J. Margolis1, Maria Ana Gomez1, Steve S. Raman1, Carolyn E. Mountford3,4

1UCLA, Los Angeles, California , USA; 2West Virginia University, Morgantown, West Virginia, USA; 3Brigham and Women's Hospital, Boston, Massachusetts, USA; 4Harvard Medical School, Boston, Massachusetts, USA

Polyamines such as spermidine and spermine play a critical role in cell proliferation and differentiation in cancer. Overlap of metabolite resonances is a major concern in conventional one-dimensional (1D) MR Spectroscopy (MRS), hence spectral-editing techniques either based on signal subtraction or multiple-quantum filter have been proposed and tested in human brain in vivo. A goal of this work was to implement a MEGA-based spectral editing sequence on a 3T MRI scanner, to optimize the technique using prostate phantom, and to evaluate the feasibility of detecting spermine/ spemidine in healthy human prostates using an external phased-array matrix coil assembly.


14:00         3239.     Optimized MRS of Neurotransmitters: How Far Do You Need to Go?

Computer 25

Paul Mullins1,2, Hongji Chen2, Jing Xu2, Arvind Caprihan2, Charles Gasparovic2,3

1Bangor University, Bangor, UK; 2The MIND Research Network, Albuquerque, New Mexico, USA; 3University of New Mexico, Albuquerque, New Mexico, USA

Standard and optimized MRS sequences for the detection of Glutamate and other neurotransmitters are compared for test re-test reliability.


14:30         3240.     High Speed Multi-Voxel Thermography with Free Induction Decay Echo Planar Chemical Shift Imaging

Computer 25

Matthew A. Neimark1, Scott Henneman2, Yingli Yang2, Jae Choi2, Angelos Aristeidis Konstas3, Melvyn B. Ooi, Hamed Mojahed2, Andrew F. Laine2, John Pile-Spellman2, Truman R. Brown2

1Columbia University, New York, New York, USA; 2Columbia University, New York, USA; 3Massachusetts General Hospital, Boston, USA

In this study, we present a fast method of performing spectroscopic imaging using free induction decay echo planar chemical shift imaging (FID EP-CSI).  This technique was performed on a phantom made up of Ringer’s lactate and 10 mM NAA.  The phantom was cooled from 38 to 29°C while temperature was continuously monitored, and 13 FID EP-CSI acquisitions were performed.  Each acquisition was 28 seconds.  This is 12 times faster than conventional CSI. For voxels in a central region, the overall regression for  NAA-H8O difference (δNAA-H8O)  vs. temperature (±95% confidence intervals) was T=(100.67±1.07)δNAA-H8O+300.36±2.86 (R2=0.9967; rms=0.16°C).


15:00         3241.     Fully Automated Shimming for High Lipid Regions Using Phased Arrays at 3T

Computer 25

Gamaliel Isaac1, Jeremy Magland, Hoby Patrick Hetherington2

1University of Pennsylvania, Philadelphia, Pennsylvania, USA; 2Yale University, New Haven, Connecticut, USA

We have developed a robust fully automated method for shimming regions of the body with high lipid content which is compatible with phased array detection. The method utilizes multi evolution delay B0 maps to generate high accuracy while retaining a large bandwidth for poor starting homogeneity. The method includes an embedded Dixon image to identify fat and water content such that the chemical shift due to lipid is corrected for allowing for the use of arbitrary evolution times. To demonstrate the method we have applied it to shim the human calf at 3T on a Siemens Trio system.


13:30         3242.     SVD 8-Channel Coil Combine for 2D Chemical Shift Imaging (CSI) MRI

Computer 26

Mithun Diwakar1, Mingxiong Huang1,2, Roland R. Lee1,2, Rebecca J. Theilmann1

1UCSD, La Jolla, California , USA; 2VA San Diego Healthcare System, San Diego, California , USA

This work describes a novel method for combining 2D Chemical Shift Imaging (CSI) data recorded by 8 independent phased array coils (8-channel GE head coil).  Singular Value Decomposition (SVD) is a form of dominant mode analysis that can be used to combine time decay signals.  The work was carried out on a phantom containing physiologic concentrations of key metabolites found in the brain (NAA, Ch, Cr). The advantages of SVD over conventional methods of combining signals from multiple coils include preservation of phase-information, automatic zero-order phasing, and no need of a priori information.


14:00         3243.     Improved Spectral Quality Through Enhanced Shimming on a Clinical Platform at 3T and 7T

Computer 26

Ralf Mekle1,2, Giulio Gambarota1, Vladimir Mlynarik1, Rolf Gruetter1,3

1Ecole Polytechnique Federale de Lausanne, Lausanne, Switzerland; 2University of Lausanne, Lausanne, Switzerland; 3Universities of Lausanne and Geneva, Lausanne and Geneva, Switzerland

Reliable localized shimming is an essential prerequisite for obtaining high-quality MR spectra, especially at higher fields (≥3T). For the first time, the fast automatic shimming technique by mapping along projections (FASTMAP) and its descendant FASTESTMAP were implemented on a clinical platform of a 3T and a 7T system. In vivo proton spectra from various brain regions were acquired and showed excellent quality due to the enhanced local field homogeneity resulting from improved shimming with FASTMAP/FASTESTMAP that translated into reduced water and metabolite linewidths at both field strengths.


14:30         3244.     Application of Forward Linear Prediction Method to High-Resolution NMR Spectra in Inhomogeneous Fields

Computer 26

Hai Feng1,2, Zhiwei Chen1, Shuhui Cai1, Xiaohong Wang1, Ji Feng3, Zhong Chen1

1Xiamen University, Xiamen, People's Republic of China; 2Institute of Physics, Chinese Academy of Sciences, Beijing , People's Republic of China; 3Institute of Physics, Chinese Academy of Sciences, Beijing, People's Republ

The forward linear prediction (LP) method was applied to deal with 2D intermolecular double quantum coherence spectra from inhomogeneous fields. The results show that compared to normal discrete Fourier transform, the use of forward LP extrapolation can shorten sampling time by a factor of eight or more at the same level of sensitivity and resolution. It can effectively extend the data sets acquired from inhomogeneous fields even for shorter data records and lower signal-to-noise ratio.


15:00         3245.     High-Quality MR Spectroscopy of the Human Brain with Full Signal Intensity at Echo Times Below 6 Ms on a Clinical Platform at 3T and 7T

Computer 26

Ralf Mekle1,2, Vladimir Mlynarik1, Giulio Gambarota1, Martin Hergt3, Gunnar Krueger3, Rolf Gruetter1,4

1Ecole Polytechnique Federale de Lausanne, Lausanne, Switzerland; 2University of Lausanne, Lausanne, Switzerland; 3Siemens Medical Solutions-CIBM, Lausanne, Switzerland; 4Universities of Lausanne and Geneva, Lau

The implementation of the spin echo full intensity acquired localized (SPECIAL) spectroscopy technique on a clinical platform was taken to the next level by combining interleaved water suppression (WS) and outer volume saturation (OVS), optimized sequence timing, and large B1 fields producing coils in addition to improved shimming. High-quality single voxel spectroscopy (SVS) data of the human brain were acquired at TEs below 6 ms on 3T and 7T systems. The high SNR of the spectra enabled reliable metabolite quantitation at both field strengths. Moreover, the enhanced sensitivity at the higher B0 field allowed a twofold reduction in scan time.


13:30         3246.     Automating Brain Tumour Classification Using High Resolution Magic Angle Spinning Data

Computer 27

Jean-Baptiste Poullet1, Daniel Monleon2, M. Carmen Martinez-Bisbal3,4, Bernardo Celda3,4, Sabine Van Huffel5

1Katholieke Universiteit Leuven , Leuven, Belgium; 2Fundación Investigación Hospital Clínico Universitario Valencia, Valencia, Spain; 3University of Valencia, Spain; 4Networking Research Center on Bioengineering

The limited success of in vivo MRS to classify some brain tumor types tends to encourage the use of other data types. Thanks to their narrow line widths and their large signal-to-noise ratios, high resolution magic angle spinning (HR-MAS) data provides much more information than in vivo MRS. Since biopsy extraction is a routine procedure in the clinical practice, incorporating HRMAS in the decision system is a reasonable solution to improve brain tumor diagnosis. This study propose a fully automated procedure to classify HR-MAS spectra.


14:00         3247.     Proton Decoupled 31P MRS of Head and Neck Tumors in Vivo at 1.5T and 3T [Not Available]

Computer 27

Sungheon Kim1, Sanjeev Chawla1, Laurie A. Loevner1, Harry Quon1, Eric J. Sherman1, Gregory S. Weinstein1, Harish Poptani1

1University of Pennsylvania, Philadelphia, USA

The purpose of this study was to implement proton decoupled 31P MRS at 3T for assessing smaller tumors and to investigate its feasibility in predicting treatment response in head and neck tumors. Proton decoupled 31P MRS data were acquired from eleven patients who were treatment naïve. Substantial increase in SNR with smaller voxel sizes was achieved at 3T as compared to 1.5T.  In a small cohort of patients, studied at 1.5T, 31P MRS studies partial responders exhibited higher PME/βNTP and PDE/βNTP ratio than complete responders indicating the potential of 31P MRS in prediction of treatment response.


14:30         3248.     In Vitro Metabolites Limit of Detection by Localised NMR Spectroscopy Using Micro Coils

Computer 27

Nicoleta Baxan1, Aziz Kadjo1, Guillaume Pasquet1, Jean-François Chateaux1, André Briguet1, Pierre Morin1, Danielle Graveron-Demilly1, Latifa Fakri-Bouchet1

1Université Lyon1, Villeurbanne, France

We present a new concept of receiver planar micro coil fabricated by electroplating technique. The innovative part of this work concerns:

- Implemented MR instrumentation at micro-scale,

- Restricted volumes detection by MR spectroscopy and imaging.

The spectrum of a solution containing eleven MR-observable 1H metabolites in human brain (50 mM) is presented, the concentration limit of detection (LODc) for the Choline and NAA case are estimated at 3.3 mM and 10.4 mM respectively. The measurements reproducibility was established using six micro coil prototypes.

The micro coils performance improvement open the way to highly spatially resolved explorations on animal model.


15:00         3249.     Diffusion-Weighted 1H NMR Single Voxel Spectroscopy at 3T and 7T

Computer 27

Daniela Wagegg1, Ralf Lützkendorf2, Wolfgang Dreher3, Claus Tempelmann4, Jörg Stadler5, Johannes Bernarding2

1Institute for Biometry and Medical Informatics, Medical  Faculty, University of Magdeburg, Magdeburg, Germany; 2Institute for Biometry and Medical Informatics, Medical Faculty, University of Magdeburg, Magdeburg, Germany

We implemented Diffusion-weighted Single Voxel Spectroscopy on a 3T- and 7T-MR-Scanner. The Sequence was based on a STEAM-Sequence. The DW-gradients where applied simultaneously in each direction. In phantom studies, this allowed the calculation of the ADC values of several brain metabolites successfully.


Non-Proton MRI

Hall D                                   Thursday 13:30-15:30                                                                                                                                           

13:30         3250.     Sodium Mapping in Focal Cerebral Ischemia in the Rat by Quantitative 23Na MRI

Computer 28

Victor E. Yushmanov1, Boris Yanovski1, Alexander Kharlamov1, George LaVerde2, Fernando E. Boada2, Stephen C. Jones1

1Allegheny-Singer Research Institute, Pittsburgh, Pennsylvania, USA; 2University of Pittsburgh, Pittsburgh, Pennsylvania, USA

23Na twisted projection MRI was validated as a quantitative technique to assess local brain sodium concentration ([Na+]br) every 5.3 min after MCAO.  The MRI protocol included a 0.4-ms echo-time, a B1 mapping, and 0-154 mM NaCl calibration standards.  [Na+]br values were obtained by MRI and flame photometry in exactly the same ROIs of ~0.5 mm3 size.  The Bland-Altman comparison of the two techniques in normal and ischemic cortex and caudate putamen of seven rats yielded a mean bias and limits of agreement of -4%±42% of average.  A linear increase in [Na+]br was observed at 1-6 hours after MCAO.


14:00         3251.     Sodium MRI with Triple Quantum Filter and Inversion Recovery at 7T

Computer 28

Guillaume Madelin1, Niels Oesingmann2, Glyn Johnson1, Alexej Jerschow1, Matilde Inglese1

1New York University, New York, New York, USA; 2Siemens Medical Solutions USA, New York, New York, USA

This study demonstrates the feasability of Sodium MRI at 7T with Triple Quantum Filter (TQF) and Inversion Recovery (IR) in differentiating mobile vs. less mobile 23Na nuclei in phantoms. The combination of TQF and IR can give complementary informations about the sodium environment and allow a better differentiation of the intracellular and extracellular compartments in biological tissues. Future studies will focus on TQF and IR 23Na MRI on human brain in vivo at 7T in order to assess the intracellular sodium concentration, with the goal of localizing pathologies.


14:30         3252.     Clean Separation of Bound vs. Free Sodium by 23Na Inversion Recovery

Computer 28

Peng Rong1, Ravinder R. Regatte2, Alexej Jerschow1

1New York University, New York , New York, USA; 2New York University, New York, New York, USA

Monitoring the bound sodium pool often allows one to characterize tissue disorders, such as osteoarthritis, or cell dysfunction. Separation methods have been used based on residual quadrupolar interactions, or slow molecular tumbling. In the current study, we demonstrate the feasibility of employing the inversion recovery (IR) sequence to selectively detect the bound or the free sodium pools in cartilage tissue. The advantages of this method are its simplicity, the ability to selectively detect either the ordered or free sodium signal, the use of only a small phase cycle, and the independence of residual quadrupolar couplings.


15:00         3253.     23Na DQF Signal Induced by Paramagnetic Shift Reagents: Dependence on the Pseudo-Contact Shift

Computer 28

Peng Rong1, Gil Navon2, Alexej Jerschow1

1New York University, New York , New York, USA; 2Tel Aviv University, Tel Aviv, Israel

23Na NMR/MRI in combination with paramagnetic shift agents is often used to separate the intra- from the extracellular sodium components. In addition to shifts, we recently reported relaxation effects which lead to the appearance of double-quantum coherences in isotropic phases and without slow motion. Here we show that these effects correlate with the pseudo-contact shift induced by the agents by examining the effects of the LnDOTP series.


13:30         3254.     Sodium MRI Using a Density Adapted 3D Radial Acquisition

Computer 29

Armin Michael Nagel1, Frederik Bernd Laun1, Marc-André Weber1, Lothar Rudi Schad

1German Cancer Research Center, Heidelberg, Germany

A density adapted 3D Radial sampling scheme (DA-3D-RAD) was implemented. The readout gradients of the DA-3D-RAD are switched constantly up to a k-space radius k0. Beyond this radius the gradient’s amplitude is reduced such that the sampling density in all spherical shells is kept constant. The benefits for sodium MRI compared to conventional 3D Radial sampling are demonstrated. In vivo sodium brain and phantom imaging was performed. This technique leads to a higher SNR compared to conventional radial sequences and improved resolution.


14:00         3255.     Sodium Imaging on a Whole-Body 7T Scanner: SNR and Resolution Benefits

Computer 29

Yongxian QIAN1, Yik-Kiong Hue1, Tiejun Zhao2, Tamir S. Ibrahim1, Fernando E. Boada1

1University of Pittsburgh, Pittsburgh, Pennsylvania, USA; 2Siemens Medical Solutions USA, Pittsburgh, Pennsylvania, USA

This study demonstrates sodium (23Na) images of a healthy human brain acquired on a whole-body 7T scanner. The signal-to-noise ratio (SNR) of the 7T images was increased by a factor of 3.5 in comparison with the images acquired on a 3T scanner with the same acquisition parameters. The SNR gain immediately resulted in an increase in spatial resolution of the 7T image from 3.44mm to 1.72mm.


14:30         3256.     31P Imaging of the Human Brain with Balanced SSFP  - Preliminary Results [Not Available]

Computer 29

Jochen Leupold1, Roza Umarova2, Jürgen Hennig1, Cornelius Weiller2, Holger Kaube2

1University Hospital Freiburg, Dept. of Diagnostic Radiology, Medical Physics, Freiburg, Germany; 2University Hospital Freiburg, Dept. of Neuroradiology, Freiburg, Germany

Magnetic Resonance Spectroscopy of 31P is a promising tool for the examination of several pathologies and metabolic processes. A beneficial reduction of total scan time could result from utilisation of fast pulse sequences, which can acquire spatial and spectroscopic information at the same time. We show preliminary results of imaging 31P in the brain with a balanced SSFP sequence, as this sequence has potential to be the basic signal generating sequence in several fast spatial-spectroscopic methods due to its high steady state signal.


15:00         3257.     Assessment of SNR and Detection Sensitivity of F-UTSI

Computer 29

Muhammed Yildirim1,2, Jochen Keupp3, Klaas Nicolay2, Rolf Lamerichs1

1Philips Research, Eindhoven, Netherlands; 2Eindhoven University of Technology, Eindhoven, Netherlands; 3Philips Research, Hamburg, Germany

F-uTSI (Fluorine ultrafast Tutbospectroscopic Imaging) is a Turbo Spin Echo (TSE) based method developed for imaging and detection of 19F based contrast agents by avoiding the well known chemical shift. Here, the preliminary results of performance assessment of the two basic variants of the method employing cartesian and pseudo-radial sampling of the k-space are presented. A small part of the potentially large parameter space was explored for two different perfluorocarbon compounds; perfluoroctyl bromide (PFOB) and perfluoro crown teher (PFCE), by altering the field the field of view and TR and the corresponding detection limits are investigated.


Measurement of Perfusion & Permeability Using Contrast Agents

Hall D                                   Monday 14:00-16:00                                                                                                                                             

14:00         3258.     Sampling the Arterial Input Function in T1 Weighted Dynamic Contrast Enhanced Perfusion

Computer 32

Adam Espe Hansen1,2, Henrik Bodil Wiberg Larsson1

1Glostrup Hospital, University of Copenhagen, Denmark

When using dynamic contrast enhanced (DCE) MRI to assess cerebral blood flow (CBF), correct determination of the arterial input function (AIF) is critical to CBF quantification. With T1-weighted DCE-MRI, we demonstrate the result of the partial volume effect (PVE) on CBF quantification in vivo. The larger vasculature can easily be identified and a PVE on the AIF can be introduced by displacing the AIF from the vessel centre. We further propose and test a method we denote venous normalization to compensate for PVE. This method might in particular be utilized to correct local arterial input functions.


14:30         3259.     Correcting Susceptibility Artifacts in Arterial Input Function (AIF) for Dynamic Contrast Enhancement Magnetic Resonance Imaging (DCE-MRI) at 3T

Computer 32

Poe-Jou Chen1, Wei-Ting Zhang2, Rakesh K. Jain3, T T. Batchelor3, A Gregory Sorensen2

1Massachusetts Institute of Technology, Cambridge, Massachusetts, USA; 2Athinoula A. Martinos Center for Biomedical Imaging, Charlestown, Massachusetts, USA; 3Massachusetts General Hospital, Charlestown, Massachusetts, USA

Dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) is a non-invasive imaging technique that has the ability to study tumor vascular functions. It has been widely used for a range of clinical oncologic applications including cancer detection, grading, and evaluation of therapeutic response. Unfortunately, in high field MRI (3T), the image signal is prone to susceptibility effects due to the increased relaxivity of contrast agent. In this abstract, we propose a novel method that could fully compensate the susceptibility effect and restore the full range of plasma concentration dynamic curve. The results demonstrated that, despite severe T2* effects embedded in the DCE-MRI data, the technique is able to reconstruct the plasma concentration time course and provide us a more accurate vascular input function


15:00         3260.     A Blood Circulatory Model to Estimate the Arterial Input Function in MR Brain Perfusion Studies

Computer 32

Hassan Bagher-Ebadian1,2, Kourosh Jafari-Khouzani1, Hamid Soltanian-Zadeh1,3, James R. Ewing1,4

1Henry Ford Hospital, Detroit, Michigan, USA; 2Amir-Kabir University of Technology, Tehran, Iran; 3University of Tehran, Tehran, Iran; 4Oakland University, Rochester, Michigan, USA

A mathematical model of Contrast Agent(CA) concentration in the circulatory system as a function of time is of interest since it may allow the description of the AIF based on the Intravenous (IV) injection function  In this study, as a building block, the concentration-time profile in the circulatory system for each compartment was modeled by simple physical and pharmacokinetic assumptions using the Fick equation and Kety’s model. A complete model of the CA concentration as a function of time in the circulatory system was then constructed by combining those building blocks using typical flow and volume parameters for the various compartments. Using a model of the IV bolus injection, its results were compared to MR perfusion (T2*) signal, indicate that this model is a good candidate to be used to define a cost function for detection of the AIF in MR brain perfusion studies.


15:30         3261.     The Use of Phase to Measure the Arterial Input Function for Quantitative T1-Weighted DCE-MRI in Human Brain Tumors

Computer 32

Claire Foottit1, Greg O. Cron2, Matthew Hogan2, Thanh Nguyen2, Ian Cameron,12

1Carleton University, Ottawa, Canada; 2Ottawa Health Research Institute, Ottawa, Canada

When measuring perfusion quantitatively in tumors with dynamic contrast-enhanced T1-weighted MRI, it can be challenging to measure the arterial input function (AIF) in large vessels.  Blood flow and saturation effects can lead to incorrect conversion of signal magnitude to contrast agent concentration.  The signal phase, however, is largely immune to such effects, potentially providing improved AIF measurement with no added imaging time or pulse sequence modification.  Here, we used this technique to measure quantitative perfusion (Ktrans) in human brain tumors.


14:00         3262.     Utilization of Principal Component Analysis for Improved Perfusion Measurements in Highly Undersampled Radial DCE-MRI

Computer 33

Junyu Guo1, Mark A. Rosen1, Hee Kwon Song1

1University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania, USA

We investigate the feasibility and accuracy of principal component analysis (PCA) for radial DCE-MRI. It is shown that with judicious selection of principal components, PCA can effectively remove image streaking and reduce noise in a highly undersampled radial DCE-MRI data set, permitting accurate, pixel-wise measurement of the perfusion parameters.


14:30         3263.     Assessment of Image Reconstruction Methods for Subsampled DCE-MRI

Computer 33

Florian Knoll1, Franz Ebner2, Stephen Keeling3, Rudolf Stollberger1

1TU Graz, Graz, Austria; 2Medical University Graz, Graz, Austria; 3University of Graz, Graz, Austria

Undersampled imaging techniques, in combination with advanced image reconstruction methods like HYPR or parallel imaging, have the potential to deliver high resolution DCE-MRI data sets in spatial and temporal domain, which can be used for the identification of pharmacokinetic parameters. It is, however, not clear to which extent these techniques change the time course of contrast enhancement, in particular for the arterial input function. The performance of four state of the art reconstruction methods is evaluated in this work. It is shown that the estimation of pharmacokinetic parameters can be improved significantly using these undersampled imaging techniques.


15:00         3264.     Accelerating Dynamic MRI with Efficient Multiple Acquisitions by SPEED Using Shared Information

Computer 33

Zheng Chang1, Jim Ji2, Qing-San Xiang3, Fang-Fang Yin1

1Duke University, Durham, USA; 2Texas A&M University, College Station, Texas, USA; 3University of British Columbia, Vancouver, Canada

The efficient multiple acquisition method using Skipped Phase Encoding and Edge Deghosting (SPEED) has been successfully demonstrated in water-fat imaging with double acquisitions. In this work, it is further developed to accelerate dynamic MRI.  In dynamic MRI, multiple acquisitions of different frames are spatially correlated, and thus share similar spatial information.  By taking advantage of the shared information, dynamic MRI is accelerated by SPEED with factors greater than that achievable with a single acquisition.  In this work, a dynamic contrast enhanced mice tumor study is accelerated by a factor of 2, with results comparable to the images without acceleration.


15:30         3265.     Rapid Steady State T1 Method for Cerebral Blood Volume Fraction Mapping Using SINEREM as Contrast Agent and a Three Dimensional Projection Reconstruction Acquisition Mode

Computer 33

Adriana Teodora Perles-Barbacaru1, Laurent Lamalle1, Emmanuel Barbier1, Christoph Segebarth1, Hana Lahrech1

1UMR-S 836 INSERM-UJF-CEA Functional & Metabolic Neuroimaging, La Tronche Cedex, France

The USPIO SINEREM is used for cerebral blood volume fraction (CBVf) mapping with the Rapid Steady State T1 (RSST1) method. A steady state signal for at least one hour is obtained in rats after an intravenous injection of 0.2 mmol/kg SINEREM and was exploited for CBVf mapping in healthy and RG2 glioma bearing rats with the RSST1 method in a 3D projection reconstruction acquisition mode enabling short echo time and with a susceptibility based steady state method for comparison. In opposite to results reported for the C6 tumor model, SINEREM seems to leak from the microvasculature in the RG2 tumor model.


DTI of the Damaged Brain

Hall D                                   Monday 14:00-16:00                                                                                                                                             

14:00         3266.     Serial Changes in Corpus Callosum Diffusion Tensor Imaging (DTI) Metrics in Moderate Traumatic Brain Injury (TBI) and Its Correlation with Neuro-Cognitive Functions

Computer 34

Mazhar Husain1, Raj Kumar1, Rakesh K. Gupta2, Khader M. Hasan3, Mohammad Haris2, Atul Agarwal1, Ponnada A. Narayana3

1Chhatrapati Shahuji Maharaj Medical University, Lucknow, India; 2Sanjay Gandhi Postgraduate Institute of Medical Sciences, Lucknow, India; 3University of Texas Medical School at Houston, Houston, USA

Serial DTI within 2 weeks and at 6 months after TBI was performed on 38 patients with TBI [frontal (n=12), temporal (n=6), fronto-temporal (n=9) and multifocal (n=11)]. Neuropsychological tests (NPT) were performed at follow-up study and 30 age/sex matched controls. DTI was also performed in controls. The fractional anisotropy (FA) and mean diffusivity (MD) were quantified from different region of the corpus callosum (CC) in patients and controls. Decreased FA in callosal regions on follow-up study compared to controls was observed in different groups. We conclude that widespread primary abnormalities in acute stage and secondary damage after 6 months in the CC can be demonstrated on DTI. These DTI abnormalities significantly correlate with some of the NPT.


14:30         3267.     Cerebral Diffusion Tensor Imaging (DTI) and in Vivo Proton MR Spectroscopy (PMRS) in Patients with Fulminant Hepatic Failure (FHF)

Computer 34

Rakesh K. Gupta1, Sona Saksena1, Vijan Rai1, Vivek Anand Saraswat1, Ram KS Rathore2, Ankur Purwar2, Manoj Kumar1, M A. Thomas3

1Sanjay Gandhi Postgraduate Institute of Medical Sciences, Lucknow, India; 2Indian Institute of Technology, Kanpur, India; 3David Geffen School of Medicine at UCLA, Los Angeles, USA

In vivo PMRS and DTI data were acquired from FHF patients (n=10) and controls (n=10). Five of the 10 patients, had a repeat imaging after three weeks. N-acetylaspartate, choline (Cho), glutamine (Gln), glutamine/glutamate (Glx), and myoinositol ratios were calculated with respect to creatine (Cr). Fractional anisotropy (FA) and mean diffusivity (MD) were quantified on different white and gray matter regions. Patients exhibited significantly increased Gln/Cr and Glx/Cr ratios compared to controls. Significantly decreased Cho/Cr was observed in deceased patients compared to controls. In patients, significantly decreased MD and FA values were observed in different brain regions compared to controls. In follow-up study, MD and FA values showed an insignificant increase.


15:00         3268.     Longitudinal Diffusion Tensor MR Imaging Study of Radiation Induced White Matter Damage in a Rat Model

Computer 34

Silun Wang1, Chung Nga Tam1, Ed X Wu1, Ho-Fai Lau1, Deqiang Qiu1, Lucullus H.T. Leung2, Pek-Lan Khong1

1The University of Hong Kong, Hong Kong, Hong Kong; 2Princess Margaret Hospital, Hong Kong, Hong Kong

We evaluate the longitudinal changes in DTI indices and its histological correlates in a radiation induced white matter (WM) injury rat model.

The results show that radiation induced WM injury is reflected by significant reduction in FA and ¦Ë// as early as 4 weeks after injury, prior to T2WI signal changes. These changes correlate with astrocytic hypertrophy, suggesting that the relative abundance of astrocytes influence ¦Ë// in the early changes of radiation induced WM injury, and this occurs before necrosis, axonal loss and demyelination.  Therefore, FA and ¦Ë// may be biomarkers for early detection of radiation induced WM injury.


15:30         3269.     Alteration in DTI Metrics and Volume of the Mamillary Body in Patients with Hepatic Encephalopathy Secondary to Non-Alcoholic Cirrhosis

Computer 34

Rakesh K. Gupta1, Vivek A. Saraswat1, Pooja Upreti1, Rajendra Singh1, Jitesh K. Singh2, Richa Trivedi1, Sunil Kumar1, Ram KS Rathore2

1Sanjay Gandhi Postgraduate Institute of Medical Sciences, Lucknow, India; 2Indian Institute of Technology, Kanpur, India

Diffusion tensor imaging (DTI) was performed in 28 patients with end stage chronic liver disease and 25 age/sex matched controls. Mamillary body volume and DTI metrics in mamillary body were quantified by using in-house JAVA based software. Significantly decreased fractional anisotropy (FA) and linear anisotropy (CL) with increased spherical isotropy (CS) and mean diffusivity (MD) values were observed in patients compared to controls. No change in volume of mamillary body was observed between patients and controls. Absence of the changes in the volume of the mamillary bodies compared to controls suggests that DTI is more sensitive for the early detection of changes due to thiamine deficiency in these patients.


Diffusion Modelling

Hall D                                   Monday 14:00-16:00                                                                                                                                             

14:00         3270.     Diffusion Tensor Imaging in Glioblastoma Multiforme and Brain Metastases: The Role of P, Q, L and FA [Not Available]

Computer 35

Chris Steward1,2, Wayland Wang1, Patricia Desmond1,2

1University of Melbourne, Melbourne, Australia; 2Royal Melbourne Hospital, Melbourne, Australia

Micro-invasive tumour cells, which are not detected on conventional imaging, contribute to poor prognoses for patients diagnosed with glioblastoma multiforme (GBM; WHO grade IV). Diffusion tensor imaging (DTI) shows promise in being able to detect this infiltration. This study aims to detect a difference in diffusion properties between GBM (infiltrative) and brain metastases (non-infiltrative).  In particular, to compare the diffusion tensor metrics p, q, L, and FA from tumoural and peritumoural regions of glioblastoma multiforme and metastatic brain tumours 2/ To determine whether these parameters can be correlated with the type of tumour and the extent of infiltration into surrounding white matter 3/ To determine whether these parameters, and more broadly DTI, has a significant clinical meaning, and thus whether it should be included in imaging protocols for suspected brain tumour and for treatment planning.


14:30         3271.     About "Axial" and "Radial" Diffusivities

Computer 35

Claudia Angela Michela Wheeler-Kingshott1, Mara Cercignani1,2

1Institute of Neurology, UCL, London, UK; 2Fondazione Santa Lucia, Rome, Italy

DTI allows the quantitative assessment of diffusion anisotropy in tissues. It is well known that the DT can be diagonalised, determining three eigenvectors and their eigenvalues.  We have questioned the rationale that underpins the relationship between axial and radial diffusivities and specific biophysical substrates, based on the already established knowledge of the uncertainty of the eigenvectors/values measures. Using two healthy-controls and two people-with-MS we have demonstrated what kind of serious interpretation errors can arise when comparing one or more eigenvalues of the DT across datasets. Our results are strongly supporting the not-yet-recognised need for including the eigenvectors when comparing eigenvalues.


15:00         3272.     Quantitative Relations of Axial and Radial Diffusivities to Anisotropy Indices in Diffusion Tensor Imaging

Computer 35

Ling-chih Lin1, Jianhui Zhong1

1University of Rochester, Rochester, New York, USA

Sensitivities of radial and axial diffusivities with respect to other diffusion anisotropy indices (DAIs) were evaluated numerically. Monte Carlo Simulation was performed to evaluate the effect of the signal to noise ratio (SNR) to their accuracy. Correlations between the axial and radial diffusivities and other DAIs were examined to facilitate the optimal selection of diffusion anisotropy measurement parameters.


15:30         3273.     Three Novel Methods for Studying Complicated Diffusion Behavior Using Simple Capillary Structures

Computer 35

Nathan Yanasak1, Qun Zhao2, Tom C.-C. Hu1, Jerry Allison1

1Medical College of Georgia, Augusta, USA; 2University of Georgia, Athens, USA

Although DTI has shown great clinical potential for studying a variety of neurological conditions, procedures and equipment for quality assurance of clinical data are still in development.  In particular, noise can bias anisotropy measurements, yet phantom designs are generally limited to simple anisotropic structures less characteristic of tissue.  This study introduces three new techniques to assist in the characterization of data quality for complicated tissue-like structures.  Images acting as input are acquired using a phantom with capillary structures.  In this manner, data quality from images of complex structures can be inferred from a QA phantom.


14:00         3274.     Constrained Single Step Diffusion Tensor Reconstruction Using Cholesky Decomposition

Computer 36

Murat Aksoy1, Roland Bammer1

1Stanford University, Stanford, California , USA

In DTI, the diffusion model requires the tensor to be positive definite. Several methods have been proposed to ensure positive definiteness, such as replacing negative eigenvalues or constraining tensors to be positive definite using matrix decomposition. In this study, we propose a single step non-linear tensor estimation scheme that utilizes Cholesky decomposition to guarantee the positive definiteness of the reconstructed diffusion tensors. The presented algorithm estimates the diffusion tensor directly from the unity of all k-space data in a non-linear fashion and it is especially effective in correcting gross patient motion in the case of multi-shot DTI scans.


14:30         3275.     Using Fractional Anisotropy Neighbourhood Information in a Bayesian Based Regularisation Technique for DTI

Computer 36

Marta Morgado Correia1, Tim Hosey1, Sally G. Harding1, Thomas Adrian Carpenter1, Guy B. Williams1

1University of Cambridge, Cambridge, UK

A new regularisation method for DT-MRI, which is capable of improving the confidence in the FA maps obtained from diffusion weighted MRI datasets, is introduced. The idea behind this prior is that the variation of FA along a fibre tract should be smooth, and therefore if there is a tract connecting two neighbour voxels, the FA variation between these two voxels should be small. The regularisation is applied to the priors of a MCMC model rather than the data itself, meaning that the fit is biased towards spatially consistent solutions but this only when supported by the data.


15:00         3276.     Modelling Diffusion-Weighted Steady-State Free Precession in Terms of the Reciprocal Spatial Wave Vector and Non-Gaussian Diffusion Probability Density Functions

Computer 36

Jennifer Andrea McNab1, Karla L. Miller1

1University of Oxford, Oxford, UK

Diffusion-weighted steady-state free precession (DW-SSFP) accumulates signal from multiple echoes over several TRs yielding a strong sensitivity to diffusion with short gradient durations and imaging times. DW-SSFP is thus of great interest as a potential method for high angular and spatial resolution diffusion imaging. The DW-SSFP signal is well characterized for isotropic, Gaussian diffusion, however, it is unclear how the multi-echo signal propagates for inhomogenous media. In this study, the DW-SSFP signal equation is presented for the first time in terms of the reciprocal spatial wave vector (<B>q</B>) and an arbitrary diffusion probability density function pdf (P(r, δ)).


15:30         3277.     Toroid-Based Characterization of Cardiac DT-MRI

Computer 36

Choukri Mekkaoui1, Marcel P. Jackowski2, Albert J. Sinusas1

1Yale University School of Medicine, New Haven, USA; 2Institute of Mathematics and Statistics, São Paulo, Brazil

The aim of the present study is to introduce a novel toroid-based representation of diffusion tensor fields to improve myofiber visualization and macrostructure analysis. A new diffusivity index, the toroidal volume (TV), and a new coefficient of anisotropy, the toroidal volume ratio (TVR), are defined. Toroidal glyph renderings from a normal canine heart were compared to ellipsoidal and superquadric glyph fields. TV and {1-TVR} maps were calculated for a DT-MRI dataset of an infarcted canine heart and compared to contemporary indices. Results demonstrate that the proposed methodology improves diffusion tensor visualization and may complement existing diffusion indices.


MRI & MRS of Cerebral Ischemia

Hall D                                   Tuesday 13:30-15:30                                                                                                                                             

13:30         3278.     Susceptibility-Weighted Imaging in Hyperacute Cerebral Ischemia

Computer 30

Masahiro Ida1, Kennichi Motoyoshi1, Hiroyuki Fukuyama1, Hisashi Yoshizawa1, Naoya Yorozu1, Keiko Hino1

1Tokyo Metroplolitan Ebara Hospital, Oota-ku, Japan

Increased vessel contrast (IVC) suggests a relative increase of intravenous paramagnetic deoxyHb and a relative reduction of oxyHb due to the impaired oxygenation (misery perfusion state). SWI can detect not only an area of perfusion impairment but also occluded artery. SWI provides important adjunct information for HIS. IVC is a useful finding to assess acute misery perfusion state without contrast media and a reliable indicator for determining whether a patient should undergo Gd-perfusion study.


14:00         3279.     Feasibility of Longitudinal Study Using Arterial Spin-Labeling Perfusion MRI in Pediatric Arterial Ischemic Stroke

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Juan Chen1,2, Daniel J. Licht3, Yong Fan1, Sabrina E. Smith3, Shannon C. Agner3, Stefanie Mason3, Robert A. Zimmerman3, Rebecca N. Ichord3, Jiongjiong Wang1

1University of Pennsylvania, Philadelphia, Pennsylvania, USA; 2Beijing Hospital, Beijing, People's Republic of China; 3the Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA

This is a longitudinal study of cerebral perfusion and lesion volume changes in three pediatric patients with acute stroke. The aim of the study was to demonstrate feasibility of pulsed arterial spin-label (PASL) perfusion MRI to follow perfusion deficits and their relation with changes in lesion volume over time. Ischemic lesions showed a trend of decreasing volume over time accompanied by decreasing perfusion within the shrinking lesion. Voxel-based scatterplot analysis of the region of diffusion restriction indicate that tissue within the lesion has relatively higher perfusion and may represent viable and potentially salvageable tissue.


14:30         3280.     Altered Regional CO2 Vasoreactivity in Patients with Ischemic Stroke Using CASL MRI

Computer 30

Peng Zhao1, David Alsop2, Magdy Selim3, Amir Abduljalil4, Peter Novak5, Lewis Lipsitz1, Kun Hu1, Sarah LaRose1, Vera Novak1

1Beth Israel Deaconess Medical Center, Boston, Massachusetts, USA; 2Radiology, Beth Israel Deaconess Medical Center,, Boston, Massachusetts, USA; 3Neurology, Beth Israel Deaconess Medical Center, Boston, Massachusetts, USA

This study investigated the regional differences in CO2 vasoreactivity (CO2VR) after stroke and their relationship to clinical outcomes. 27 subjects with chronic large vessel infarcts in the middle cerebral artery (MCA) territory were compared with 43 controls by using continuous arterial spin labeling (CASL) perfusion MRI. Impairment of CO2VR after stroke was observed which extended into additional brain regions and vascular territories not within the ischemic region.


15:00         3281.     Quantitative Assessment of Brain Mass Effect Using Mid-Brain Surface in Stroke Patients

Computer 30

Yasheng Chen1, Chung-Yi Yang2, Cheng-Hong Toh1, Hongyu An1, Allyson Zazulia3, Thomas Vedeen3, Michael Diringer3, William Powers1, Weili Lin1

1The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA; 2National Taiwan University Hospital, Taiwan; 3Washington University in St. Louis, St. Louis, Missouri, USA

The current approach for quantitatively measuring brain mass effect employs manual measurements of the 2D displacement between the altered brain midline and the putative normal midline in specific anatomical locations including the pineal body, septum pellucidum, and third ventricle.  One major limitation associated with this approach is the inability to assess the true 3D extent of brain mass effect.  An automated approach reconstructing the mid-brain surface is developed, allowing a direct assessment of mass effects through measuring the volume enclosed by the deformed and the estimated of un-deformed brain mid-surface.


13:30         3282.     White Matter Integrity But Not BOLD Response Predicts Upper Limb Motor Function in Patients After Stroke

Computer 31

mingguo qiu1, Justin Rajendra2, Warren Darling3, Robert Morecraft4, Chunchun Ni2, Andrew J. Butler2

1Southwest hospital of Third military medical university, chongqing, People's Republic of China; 2Emory University, School of Medicine, Atlanta, Georgia, USA; 3The University of Iowa, Iowa City, Iowa, USA; 4Univ

The aim was to establish the relationship between upper-extremity motor functional outcomes with the asymmetry of fractional anisotropy (FA) from DTI and with the laterality index (LI) derived from functional MRI. Seventeen patients after stroke were enrolled and measured the motor function by Wolf Motor Function Test (WMFT) and Fugl-Meyer (FM) assessment. The data showed a significant relationship between FA asymmetry of PLIC with FM and WMFT asymmetry, white matter integrity can strongly predict current motor function.  However, LI can’t predict the current clinical outcomes; no relationship was found between the LI with the FA asymmetry and clinical motor outcomes.


14:00         3283.     Assessing the Evolution of Sodium MRI with Time After Onset in Human Stroke

Computer 31

Robert Wayne Stobbe1, Muhammad Shazam Hussain2, Yusuf A. Bhagat2, Ken S. Butcher1, Derek J. Emery1, N Rizvi1, Perkash Maheshwari1, Ashfaq Schuaib1, Christian Beaulieu1

1University of Alberta, Edmonton, Canada; 2University of Alberta, Edmonton , Canada

Sodium MRI signal intensity within the ischemic lesion is shown to evolve over time after symptom onset in human acute stroke. Given significant early changes it may be possible to estimate time of onset in patients when this important factor is unknown, and possibly increase options for treatment.


14:30         3284.     Elevated Choline/Creatine Ratio in Central Nervous System Arterial Infarction: Frequency, Timing, Extent and the Effect of Echo Time

Computer 31

Metin Bora Vardar1, Gur Akansel,12, Nagihan Inan1,1, Hasan Tahsin Sarisoy1,1, Arzu Serpil Arslan1,1, Ercument Ciftci1,1, Ali Demirci1,1

1; 2Kocaeli University School of Medicine, Kocaeli, Turkey

Although the MRI diagnosis of cerebral infarction is usually straightforward with the use of diffusion-weighted imaging, infarcts first seen in the late subacute stage remain a challenge to differentiate from neoplasm. Since cytotoxic edema subsides in the late subacute period, abnormalities of apparent diffusion coefficient due to restricted water diffusion are of limited help. Hemorrhagic transformation and abnormal contrast enhancement due to blood brain barrier breakdown may further complicate the picture.


A common clinical indication for proton MRS is the differentiation of neoplastic from non-neoplastic central nervous system lesions. MRS is frequently performed to differentiate subacute infarcts from neoplasm. However, elevated choline content that may be encountered in subacute infarcts may impede the contribution of MRS in this differentiation.


In this study, we evaluated choline/Creatine ratios in cases of acute, subacute and chronic central nervous system infarction to detect the frequency, timing and the extent of the elevation in choline/Creatine ratio. Our aim was to determine if the MRS pattern in subacute infarction was sufficiently different from that which characterizes a neoplasm.


15:00         3285.     fMRI of Rehabilitation in Chronic Stroke Using MR-Compatible Robots

Computer 31

Dionyssios Mintzopoulos1,2, Loukas G. Astrakas1, Walter J. Koroshetz1, Michael A. Moskowitz1, Bruce R. Rosen1, A Aria Tzika1

1Massachusetts General Hospital, Boston, Massachusetts, USA

Using a hand motor task, we investigated brain activation after chronic stroke by combining fMRI at 3T with a novel MR-compatible hand-induced, robotic device (MR_CHIROD). Patients trained at home using a gel ball; serial neuroimaging was performed before, during, upon completion of training, and after a non-training period, to assess permanence of effects. Training significantly increased the number of activated voxels in the cortex as a function of effort level, suggesting functional cortical plasticity in chronic stroke. The result¢s persistence indicates permanence of rehabilitation, which is remarkable given that training is generally effective during a narrow window after stroke.


13:30         3286.     MRI Metrics Detected Axonal Outgrowth and Plasticity in Rat Brain After Embolic Stroke [Not Available]

Computer 32

Guangliang Ding1, Quan Jiang1, Lian Li1, Li Zhang1, Zhanggang Zhang1, Karyn A. Ledbetter1,2, Swayamprava Panda1, Siamak P.N. Davarani1,3, James R. Ewing1, Michael Chopp1,4

1Henry Ford Health System, Detroit, USA; 2Michigan State University, East Lansing, USA; 3University of Michigan, Ann Arbor, USA; 4Oakland University, Rochester, USA

Both angiogenesis and axonal outgrowth were detected as early as 1 week after stroke in sildenafil treated rats. Angiogenesis and axonal plasticity were co-localized with each other, measured histologically at 6 weeks and dynamically in vivo by MRI up to 6 weeks after stroke. This indicates that sildenafil treatment of stroke may simultaneously promote angiogenesis and axonal plasticity after embolism in rats. Local CBF in the co-localized area was increased after angiogenesis. Both elevated CBF and re-organized white matter in ischemic areas may contribute to recovery of neuronal function after stroke in rats.


14:00         3287.     Noninvasive Detection of White Matter Reorganization Enhanced by Erythropoietin Treatment in a Rat Model of Focal Ischemia Using MRI

Computer 32

Lian Li1, Quan Jiang1, Guangliang Ding1, Li Zhang1, Zhenggang Zhang1, James R. Ewing1, Michael Chopp1,2

1Henry Ford Health System, Detroit, Michigan, USA; 2Oakland University, Rochester, Michigan, USA

The objective of the present study was to noninvasively identify and monitor the progress of white matter reorganization within 6 weeks after the onset of stroke and correlate this structural change with improved neurological function using MRI. Our data in rats indicate that FA is a sensitive measure of white matter changes after stroke and provides an important noninvasive means for real-time evaluation of treatment efficacy and functional outcome. Treatment with EPO significantly enhances white matter reorganization, which correlates with local restoration of CBF and recovery of neurological function


14:30         3288.     Increased Connectivity of the Contralesional Sensorimotor Cortex at a Chronic Stage After Stroke as Studied by Manganese-Enhanced MRI in Rats

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Maurits Pieter Adriaan van Meer1,2, Wim M. Otte1, Kajo van der Marel1, J. W. Berkelbach van der Sprenkel1, Rick M. Dijkhuizen1

1University Medical Center Utrecht, Utrecht, Netherlands

Manganese-enhanced MRI was applied after injection of MnCl2 in the contralesional primary sensorimotor cortex of rats at 10 weeks after unilateral stroke. Subsequent ROI analysis of the time-course of manganese-induced R1 increases revealed increased tracer uptake and distribution in contralesional subcortical ROIs and ipsilesional cortical ROIs as compared to controls. Our data support the concept of structural remodeling of the contralesional cortex and increased connectivity with other sensorimotor network areas, which may significantly contribute to post-stroke functional recovery.


15:00         3289.     Magnetic Resonance Imaging of Delayed Administration of Manganese After Transient Focal Cerebral Ischemia

Computer 32

Kevin C. Chan1,2, Victor K. Hung1, Matthew M. Cheung1, Ke Xia Cai1, Dave K. Cheung1, Chi-tat Chiu1, Po-mak Chan1, Xiao-guang Zhao1, Sookja K. Chung1, Ed Xuekui Wu1

1The University of Hong Kong, Pokfulam, Hong Kong

This study aims to employ in vivo magnetic resonance imaging to understand longitudinally the effect of systemic MnCl2 administration on delayed secondary changes after transient middle cerebral artery occlusion (MCAO).  Results showed a significant increase in T1 signal intensities in the perilesional rim compared to the ischemic core in dorsolateral striatum 24 hours after Mn2+ injection, whereas colocalization was found between manganese-enhanced MRI pattern and immunostaining for GFAP, MnSOD and GS, likely due to their Mn-dependent upregulation against oxidative stress and glutamate excitotoxicity. Total ipsilateral infarcted volumes in the posterior parts of the brain had also significantly reduced after Mn2+ injection, illustrating the potential neuroprotective effects of manganese upon delayed postischemic administration.


13:30         3290.     Delayed T2 Changes Following Cerebral Ischaemia and Cell Transplantation with Ferumoxide-Labelled Neural Stem Cells

Computer 33

Rachael Dobson1,2, Patrizia Ferretti1, Mark F. Lythgoe1

1University College London, London, UK

Transplantation of stem cells following cerebral ischaemia has been shown to improve functional outcome. MRI contrast agents have been used to track the migration of transplanted cells towards lesions. The protamine sulphate-ferumoxide complex – FePro –enhances cell labelling. In this study, migration of neural stem cells, labelled with FePro, was monitored using MRI in a model of cerebral ischaemia. Little migration was observed. Hypointense regions on T2-weighted images developed within lesions, and iron was detected histologically, in cell treatment and control groups. These results highlight issues for cell tracking studies using MRI contrast agents in animal models of disease.


14:00         3291.     MRI Evaluation of the Effect of a COX-2 Inhibitor on BBB Permeability in a Rat Stroke Model

Computer 33

Saeid Taheri1, Eduardo Candellario-Jalil1, Eduardo Estrada1, Gary Rosenberg1, Rohit Sood1

1University of New Mexico, Albuquerque, New Mexico, USA

Recent research has demonstrated an increase in expression of cyclooxygenase (COX-2) mRNA within neurons and vascular cells and it has been postulated that COX-2 plays an important role in secondary events that amplify brain damage post-ischemia. There is additional evidence that COX-2 is involved in the increase in BBB permeability. The purpose of this study was to use MRI based BBB permeability estimation technique to evaluate the effects of nimesulide, a non-steroidal anti inflammatory drug on BBB permeability in a rat model with focal cerebral ischemia at 48h post MCAO. Initial results suggest that nimesulide is effective in reducing BBB damage 48h post ischemia and would be potential candidate for therapeutically reducing late phase brain damage post ischemic stroke.


14:30         3292.     in vivo 1H/13C MRSI of Changes in Neurotransmitter Metabolism in Rats Recovering from Stroke

Computer 33

Pieter van Eijsden1, Jet P. van der Zijden2, Robin A. de Graaf3, Rick M. Dijkhuizen2

1University Medical Center, Utrecht, Netherlands; 2University Medical Center Utrecht, Netherlands; 3Yale University, New Haven, USA

Post-stroke functional recovery has been associated with brain plasticity in the lesion borderzone, but its metabolic basis is unknown. To characterize alterations in oxidative glycolysis and neurotransmitter metabolism, we applied in vivo dynamic 1H/13C MR spectroscopic imaging after infusion of 13C-labeled glucose in rats after transient stroke. Semi-acutely, reductions in NAA levels and Glu turnover implied severe neuronal dysfunction in the lesion borderzone. At 3 weeks post-stroke, NAA levels and Glu turnover had normalized, suggestive of neuronal recovery. Our findings show that early metabolic impairment in the morphologically intact lesion borderzone recovers over time, contributing to post-stroke functional improvement.


15:00         3293.     Magnetic Resonance Spectroscopy and Imaging at 9.4T in P4 Rat Pup Brain Following Cerebral Hypoxia-Ischemia

Computer 33

Yohan van de Looij1,2, Alexandra Chatagner2, Nicolas Kunz1, Petra S. Hüppi2, Stéphane V. Sizonenko2, Rolf Gruetter1,3

1Laboratory for Functional and Metabolic Imaging, Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland; 2Division of Child Growth & Development, Department of Pediatrics, University of Geneva, Geneva, Switzerland

To define the nature of diffuse injuries of the very preterm infant, we use the model of neonatal hypoxic-ischemic injury in the 3-day old (P3) rat pup and we investigate acute and long term brain alterations using high-field MRI and MRS. At P4, the ispilateral cortex indicated significant modifications for several metabolites reflecting an energetic and functional slowing-down of the injured cortex. At P11 no significant differences between both cortices were found, ascribed to a low number of animals and possibly to intervening partial tissue repair. Relation between metabolic changes and severity of the injury requires further investigations.


13:30         3294.     In Vivo Early MRI and MRS at 9.4T of Combined Hypoxia-Hypotension and Traumatic Brain Injury in the Rat

Computer 34

Bich-Thuy Doan1,2, Fanny Noury3, Thomas Geeraerts4, Arnaud Friggeri5, Philippe Meric1, Sandra Meme3, Bernard Vigue4, Jean-Claude BeloeilL3

1CNRS, Gif sur Yvette, France; 2Orléans, France; 3CNRS, Orléans, France; 4AP-HP, University of Paris Sud, Kremlin Bicetre, France; 5AP-HP, France

Following traumatic brain injury (TBI), hypoxia and hypotension are frequent and damaging secondary insults.

The aim of this work is to characterize the traumatic injury by MRI (T2, diffusion tensor, angiography) and MRS experiments in vivo on rat brain. The final aim is to understand the role of secondary insults like hypoxia and hypotension (HH) in the development of post-traumatic brain oedema.

Using an animal model of diffuse TBI complicated by HH, we focused on post-traumatic brain oedema development using MRI combined with MRS, as well as consequences of post-traumatic perturbations on brain energy metabolism using cerebral microdialysis.


14:00         3295.     Single Voxel MR Spectroscopy with Echo Times Below 2 Ms at 16.4 T in the Rat Brain: First in vivo Results

Computer 34

David Zsolt Balla1, Sung-Tak Hong1, Gunamony Shajan1, Rolf Pohmann1, Kamil Ugurbil1,2

1Max Planck Intitute for Biological Cybernetics, Tuebingen, Germany; 2Center for Magnetic Resonance Research, Minneapolis, USA

Single voxel MRS techniques employ at least three RF-pulses to generate an echo in the selected volume and gradients to dephase magnetization in the outer region. During the time between excitation and acquisition, relaxation effects and phase modulation by J-couplings affect the NMR signal. The STEAM sequence can be applied with very short echo times to obtain localized spectra containing fast decaying components and peaks from all detectable coupled resonances. We show in vivo spectra from the rat brain acquired at 16.4 T with localized spectroscopy using echo times below 2 ms and compare them to results from the literature.


14:30         3296.     Time Courses and Correlation of Diffusion-Weighted MR and CT Imaging in Acute MCA Ischemia with Rat Model

Computer 34

Hyung Suk Seo1, Dong Gyu Na2

1dongguk university international hospital, goyangsi, Republic of Korea; 2Seoul National University College of Medicine, Seoul, Republic of Korea

Unlike ADC value, DWI signal in acute cerebral ischemia increases with time and correlates with CT density, which decrease with time. It means that the signal change of DWI after 3 hours is influenced by net water uptake in ischemic edema rather than by restricted water diffusion and DWI will be used as the predictor of ischemic injury severity like CT.


15:00         3297.     Brain Tissue Ischemic Transitions During Permanent Middle Cerebral Artery Occlusion (PMCAO) in Rats

Computer 34

Lesley May Foley1, T. Kevin Hitchens1, Brent Barbe2, Joyce A. Horner1, Edwin M. Nemoto2

1Carnegie Mellon University, Pittsburgh, Pennsylvania, USA; 2University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA

The identification of the ischemic penumbra in acute stroke is important for therapeutic intervention.  Whereas qualitative MRI perfusion and diffusion mismatch does not accurately identify the ischemic penumbra, it may be identified by quantitative measurements using ASL for perfusion and ADC with appropriate thresholds.  Using these methods, we were able to describe brain tissue ischemic transitions in the first four hours and up to three weeks after pMCAO.


13:30         3298.     Mild Hypoxic-Ischemic Brain Injury in Neonatal Rats Using Diffusion Tensor MR Imaging: A Longitudinal Study

Computer 35

Silun Wang1, Ed X Wu1, Chung Nga Tam1, Edward S Hui1, Pek-Lan Khong1

1The University of Hong Kong, Hong Kong, Hong Kong

We evaluate the longitudinal changes (D1 to D90 post-injury) in the white matter (WM) of a mild hypoxic-ischemic (HI) rat brain injury model using DTI and correlate the findings with histology. Significantly elevated ¦Ë¡Í with no change in ¦Ë// in the ipsilateral WM was found, suggesting reduced myelination in the ipsilateral WM as a consequence of mild HI injury and this was confirmed by Luxol fast blue stain. Longitudinal changes of DTI indices on the ipsilateral WM parallel changes of normal development in the contralateral WM suggesting continual maturation processes after HI injury.


14:00         3299.     Comparison of Two Methods of Assessment of Perfusion-Diffusion Mismatch in a Rodent Model of Ischemic Stroke
[Not Available]

Computer 35

Feng Chen1, Yicheng Ni1, Guy Marchal, Jie Yu1, Yasohiro Suzuki, Nobuo Nagai

1Catholic University of Leuven, Leuven, Belgium

The present study demonstrated that the PWI-ADC pattern evolves from a mismatch pattern through a match pattern to a reversed mismatch pattern after stroke onset. The PWI-ADC mismatch pattern was observed up to 72h after MCA occlusion in this animal model. There are linear correlations of volume and mismatch occurrence between e(early)PWI-i(instant)ADC and iPWI-iADC models. The PWI-ADC pattern could be defined either with ePWI or iPWI before 24h after stroke onset. The iPWI appeared more adequate compared to ePWI to define the PWI-ADC pattern at 72h.



Diffusion: Artifacts, Phantoms, QA, Reproducibility

Hall D                                   Tuesday 13:30-15:30                                                                                                                                             

13:30         3300.     Quality Assessment Through Analysis of REsiduals of Diffusion Image Fitting

Computer 36

Alexander Leemans1, Christopher John Evans1,2, Derek K. Jones1

1School of Psychology, Cardiff University, Cardiff, UK; 2GE Healthcare, Chalfont St. Giles, UK

In order to obtain reliable quantitative results, it is important to assess the quality of DTI data with respect to subject motion, distortions, signal dropouts, etc. prior to performing further analyses. In this context, we developed a comprehensive DTI quality assessment (QA) tool that provides a ‘direct feel’ and ‘global overview’ of the data in an automatic way. We show how this exploratory tool can be used to efficiently identify subject motion, signal dropouts, and image distortions, without the need to perform QA on all the individual diffusion weigthed MR images.


14:00         3301.     Analysis of Noise Corrected Diffusion Decay of Human Brain

Computer 36

Elena Olariu1, Arturo Cardenas-Blanco2, Ian Cameron,12

1Carleton University, Ottawa, Canada; 2Ottawa Health Research Institute, Ottawa, Canada

Several studies have shown that, there is a significant deviation of the MR signal, for both gray matter (GM) and white matter (WM), from the mono-exponential model; however, there is no clear consensus as to whether the diffusion decay has one or more exponential contributions. Our purpose was to carefully characterize the diffusion attenuation in WM and GM over an extended range of b-values, and to use a post-processing scheme to reduce the noise bias to see if a second exponential component could be observed.


14:30         3302.     Quality Assurance of MR Scanner on Diffusion Tensor Imaging [Not Available]

Computer 36

Zili Chu1,2, Jonathan Chia3, Zhiyue J. Wang1,2

1Baylor College of Medicine, Houston, Texas, USA; 2Texas Children's Hospital, Houston, Texas, USA; 3Philips Medical Systems, Cleveland, Ohio, USA

Diffusion Tensor Imaging (DTI) is prone to artifacts associated with EPI and strong diffusion encoding gradients. Therefore, periodically assessing the performance of the scanner on the DTI sequence is essential to ensure good image quality. Here, we propose the use of a glycerin-gel spherical phantom constructed to be similar to the human brain in terms of apparent diffusion coefficient (ADC) and T2.The temperature of the phantom is controlled during the QA data acquisition. The calculated ADC, FA, image center displacement and distortion on the DTI data of the phantom can be analyzed to  serve as indicators of the scanner performance.


15:00         3303.     A Frame-Work for DTI Quantitation, Visualization & Analysis

Computer 36

Ankur Purwar1, RKS Rathore1, RK Gupta2, D Rathore1, G Bayu1, MK Sarma1, Anup Singh1, JK Singh1, S Verma1

1IIT Kanpur, Kanpur, India; 2SGPGIMS Lucknow, Lucknow, India

DTI is an important tool to study brain white matter anatomy/abnormalities. The data processing and analysis in DTI is quite elaborate and so far no commercial and easily extendable/modifiable tool for the same is available. In view of the same, we present a tool frame-work focusing on DTI technology combining all of the above needs. It has 4 mutually independent modules namely DTI Processing Module, DTI Visualization Module, ROI Analysis Module and Tracking and Fiber data Visualization Module. The Tool can read various data formats from different scanners including the raw binary format. An automatic de-scalping procedure is also implemented.


13:30         3304.     Validation of Diffusion Tensor Imaging and Tractography of the Human Peripheral Nerve Using Small-Diameter Ex Vivo Phantoms

Computer 37

Akira Kunimatsu1,2, Masayuki Yamaguchi2, Yoshikazu Okamoto1, Izumi Anno1, Hirofumi Fujii2, Atsushi Nozaki3, Hiroyuki Kabasawa3, Manabu Minami1

1Institute of Clinical Medicine, University of Tsukuba, Tsukuba, Japan; 2Research Center for Innovative Oncology, National Cancer Center Hospital East, Kashiwa, Japan; 3GE Yokogawa Medical Systems, Hino, Japan

We aimed to develop small-diameter, flexible, ex-vivo phantoms for validation of diffusion tensor (DT) imaging and tractography of the human peripheral nerve on a clinical MR imager with standard coils. Our results suggest that DT imaging and tractography are feasible even with a 4-mm-diameter phantom on a clinical imager without any dedicated or special coil. Four or more numbers of excitations and 15 or more motion probing gradient directions may provide robust results of fractional anisotropy measurement and fiber-tracking of the human peripheral nerve.


14:00         3305.     Impact of Resolution on Tissue-Specific DTI Parameters at 3T: Roles of Partial Volume, SNR and Tissue Structure

Computer 37

Xiaogeng Feng1, Dae-Shik Kim1, Itamar Ronen1

1Boston University School of Medicine, Boston, Massachusetts, USA

With the proliferation of high field MRI scanners (B0 &[ge] 3T), it is now possible to acquire DTI data of the human brain at a reasonably high spatial resolution. Increased resolution, however, has implications on the assessment of DTI parameters such as ADC and FA that are different for white matter and cortical gray matter. This work aims to evaluate the tissue-specific effects of increased resolution in carefully segmented DTI data sets and explain the interplay between SNR, partial volume effects and macroscopic characteristics (e.g. curvature effects), which is shown to be significantly different in brain gray and white matter.


14:30         3306.     Simple, Reliable and Precise Quantitative Quality Assurance of In-Vivo Brain ADC

Computer 37

Nicholas G. Dowell1,2, Paul S. Tofts1,2

1University of Sussex, Falmer, UK; 2UCL, London, UK

Measuring diffusion with MRI is a useful and popular method of studying many pathological conditions in vivo. The apparent diffusion coefficient (ADC) is commonly used to quantify the extent of diffusion; however, there is a need for reliable quantitative quality assurance of the technique. We use decane, dodecane and tetradecane as test liquids that exhibit similar ADC values to those observed in the human brain in vivo. We demonstrate that serial measurements of ADC can be referenced to a standard temperature to avoid variation due to temperature fluctuations. The materials used here are stable, readily available and safe to handle.


15:00         3307.     Looking for the Optimal DTI Acquisition Scheme Given a Maximum Scan Time: Are More B-Values a Waste of Time?

Computer 37

Marta Morgado Correia1, Thomas Adrian Carpenter1, Guy B. Williams1

1University of Cambridge, Cambridge, UK

By using simulated data, this study has shown that the use of more than 1 b-value in DTI acquisition schemes can minimize the systematic bias of ADC and FA estimates due to the Rician noise distribution, and also produce results closer to the simulates ones and less variable due to noise and fibre rotation. In addition, the use of more than 1 b-value accounts better for the great diversity of diffusivities we find in the brain. For tractography studies, however, we should use as many sampling directions as allowed by scan time limitations.


Fiber Tracking & Connectivity Mapping

Hall D                                   Wednesday 13:30-15:30                                                              Chairs: Derek K. Jones and Mariana Lazar

13:30         3308.     In Vivo Localisation of Fibre Tracts: Optimisation of Fibre Tracking to Reduce Voxel Misclassification

Computer 30

J-Donald Tournier1,2, Fernando Calamante1,2, Alan Connelly1,2

1Brain Research Institute, Melbourne, Australia; 2University of Melbourne, Melbourne, Australia

Diffusion tractography is increasingly being used in clinical and neuroscientific applications. However, reliable tracking requires methods to resolve crossing fibres that have yet to be optimised. Here, we investigate the effects of acquisition and reconstruction parameters on the reconstructed fibre tracts estimated using sophisticated methods, by quantifying the volume of white matter misclassified as belonging or not to the tract. We show that misclassified volume is consistently reduced by using more diffusion-weighted directions and higher spherical harmonic orders. Measures of false tract and omitted tract volume also provide a means of tailoring the acquisition and reconstruction to the application.


14:00         3309.     A New Fiber Tract Color-Encoding Scheme Based on Diffusion Tensor  Model Residuals

Computer 30

Alexander Leemans1, Derek K. Jones1

1School of Psychology, Cardiff University, Cardiff, UK

Due to the multi-component nature of DTI data, distinguishing between real and artifactual observations is often non-trivial. To bridge this gap between the acquired images and the understanding of the underlying WM microstructure, specialized visualization methods have been developed that display various WM properties along the fiber tracts. However, none of these visualization approaches reflects the acquired data quality (artifacts) or Goodness-of-Fit (GoF) to the model, which is crucial in interpreting analysis results. In this context, we developed a new color-encoding scheme for visualizing fiber tracts, based on the analysis of tensor model residuals, which allows the investigation of data quality and GoF.


14:30         3310.     Combination of Distance Measures for Optimal Fiber Clustering in Diffusion Tensor Imaging

Computer 30

Daniel Güllmar1,2, Jana Langner1, Jens Haueisen2, Jürgen R. Reichenbach1

1University Hospital Jena, Jena, Germany; 2TU Ilmenau, Illmenau, Germany

From Diffusion Tensor data of the human brain one can derive beautiful fiber tracts employing deterministic algorithms in order to mimic the neuronal pathways. However it is hard to distinguish between the different tracts, although the tracts itself are easy to recognize by visual inspection. Several studies showed that one can perform clustering based on distance measures between the fiber path ways. Thus it is possible to objectively group the paths in order to distinguish between at least the major tracts. The aim of the presented study is to combine different distance measures to handle deficiencies of single distance measures.


15:00         3311.     Tracking of CE-MR-Angiography Data Using Established Approaches in DTI

Computer 30

Daniel Güllmar1,2, Andreas Deistung1, Stefan Richter1, Jens Haueisen2, Jürgen R. Reichenbach1

1University Hospital Jena, Jena, Germany; 2TU Ilmenau, Ilmenau, Germany

We propose a method to generate tractograms from CE-MR-Angiography data using existing tools designed to work on diffusion tensor data. The pseudo DT data are generated by converting the Hessian matrix derived from a multi-scale approach in order to obtain a highly anisotropic tensor representation along the vascular system. The results derived from a high resolution 3D MR angiographic extremity data set demonstrate that it is possible to reconstruct the vascular system with diffusion tensor fiber tracking tools. Only deterministic tracking was applied so far which leads to some extent to fragmentary reconstruction, which may be overcome by probabilistic tracking.


13:30         3312.     Local DTI Connectivity Estimation Using Bayesian Probability Theory

Computer 31

Joshua S. Shimony1, Adrian A. Epstein1, G Larry Bretthorst1

1Washington University School of Medicine, St. Louis, Missouri, USA

The diffusion tensor model has been used to analyze magnetic resonance diffusion data and has been successful in both neuroscientific and clinical applications.  We propose an enhancement of this model with a local connectivity parameter that better accords with the known structure of white-matter.  In addition to providing diffusion tensor parameter estimation the calculation provides the probability that a given pixel is connected to one of its nearest neighbors.  These probabilities can be used in further calculations to determine the probability of connectivity between different brain regions.


14:00         3313.     White Matter Tract Probability Atlas Derived from Diffusion Tensor Tractography of a Large Population

Computer 31

Catherine Lebel1, Luis Concha1, Gaolang Gong1, Christian Beaulieu1

1University of Alberta, Edmonton, Canada

Brain white matter is usually crudely parcellated based on lobar location in existing human brain atlases. Recent attempts to create a more detailed

white matter atlas based on information derived from diffusion tractography have been reported, but are limited by small sample sizes. We investigated the spatial variability in standard space of thirteen white matter structures defined by tractography in a group of 254 healthy volunteers. The core of the white matter structures shows high spatial overlap amongst individuals, while the edges show high variability. Our results could provide valuable information for the interpretation of voxel-based analyses.


14:30         3314.     Improving the Efficiency of Tractography by Combining DTI with Prospective Partial-Brain Q-Ball Imaging

Computer 31

Jiancheng Zhuang1, Nicolas Lori1, Christine Vidal1, Hanna Damasio1

1University of Southern California, Los Angeles, USA

This study proposed to develop a method which combines the conventional DTI and a prospective partial-brain QBI to improve the efficiency of tractography. The non-Gaussian ADC profile detected from DTI data was used to indicate which brain region to be covered by QBI. The multiple wavevector fusion (MWF) algorithm was performed in the combination of data, and multiple FACT algorithm was applied in fiber tracking. The quality of connectivity detection in this approach is sufficiently high, and the scan time is reduced by about 65.3% when compared with a similar QBI with the whole brain coverage.


15:00         3315.     Connectivity-Based Probabilistic Parcellation of the Striatum in Human Brain by Diffusion Tensor Imaging

Computer 31

mingguo qiu1, qiyu li1, jian wang2, bing xie2, shaoxiang zhang1

1Third military medical university, chongqing, People's Republic of China; 2southwest hospital of Third military medical university, People's Republic of China

The aim is to investigate the corticostriatal connections in human by DTI. The results showed the frontal projections were located to the head of the caudate nucleus and the superior part of the putamen, the insular projections to the lateral striatum, the projections from the parietal, temporal and occipital lobes overlapped to the posterior part and the inferior part of the striatum. M1 were connected to the posterosuperior part, SMA to the middle part and PMC to the anterior and posteroinferior striatum. The striatum have specific connections with the different cortex, connectivity-based probabilistic tractography and parcellation is valuable in the functional anatomy of human brain.


13:30         3316.     Diffusion Tensor Imaging Fiber Tracking of the Nigro-Striatal Fiber Tract in the Monkey Brain Using Whole Body 7T

Computer 32

Stephane Lehericy1, Essa Yacoub2, Eric Bardinet1, Romain Valabregue1, Chantal Francois1, Geoff Ghose2, Noam Harel2

1University Pierre and Marie Curie, Paris, France; 2University of Minnesota, Minneapolis, Minnesota, USA

In this work, we used 7T whole body and diffusion tensor imaging (DTI) to reconstruct the nigro-striatal fiber tract in the anesthetized macaque brain. DTI was performed using a single shot SE acquisition. The nigro-striatal fiber tract was reconstructed between the segmented substantia nigra and lenticular nucleus. The tract coursed from the medial part of the substantia nigra anteriorly toward the medial part of the globus pallidus. DTI reconstruction of the nigro-striatal fiber tract provides a marker of the nigro-striatal pathway that can be used to study basal ganglia pathology such as Parkinson’s disease.


14:00         3317.     High Resolution Probablistic Tractography in Whole, Fixed, Human Brain Using Diffusion-Weighted Steady-State Free Precession

Computer 32

Jennifer A. McNab1, Saad Jbabdi1, Sean C.L. Deoni,12, Gwenaelle Douaud1, Timothy E.J. Behrens1, Karla L. Miller1

1University of Oxford, Oxford, UK; 2Institute of Psychiatry, King's College, University of London, London, UK

This study presents a robust method for estimating the principal diffusion direction from multi-angle DW-SSFP data and demonstrates probabilistic tractography at sub-millimeter resolution in a whole, fixed human brain.


14:30         3318.     Atlas-Based Reference Tracts Improve Automatic White Matter Segmentation with Neighbourhood Tractography

Computer 32

Susana Muñoz Maniega1, Mark E. Bastin1, Andrew M. McIntosh1, Stephen M. Lawrie1, Jonathan D. Clayden2

1University of Edinburgh, Edinburgh, UK; 2UCL , London, UK

Neighbourhood tractography is a novel technique that aims to automatically segment the same fasciculus in different subjects by scoring the similarity between a predefined “reference tract” and a group of candidate tracts generated with different initial seed points. In the current work we present a means of improving the technique by generating the reference tract from an anatomical atlas. Using diffusion data from 50 volunteers we found that atlas-generated reference tracts improved the segmentation results in the four fasciculi examined, obtaining lower variation of FA within the group and percentages of visually plausible tracts of up to 82%.


15:00         3319.     Using BCP Index to Evaluate Coregistration Methods in Existing SPM2 [Not Available]

Computer 32

Shiou-Ping Lee1, Kao-Lun Wang1, Chung-Ming Chen2, Wen-Yih Isaac Tseng3

1Far Eastern Memorial Hospital, Taipei, Taiwan; 2National Taiwan University Hospital, Taipei, Taiwan; 3National Taiwan University Medical College, Taipei, Taiwan

A novel indices, Bundle Curvature Profile (BCP), was proposed as the basis to quantify the similarity of four fiber bundles to distinguish geometric significant difference. In this study, we corrected diffusion tensor imaging data using four different SPM2 built-in coregistration functions, i.e., normalized mutual information (NMI), mutual-information (MI), entropy correlation coefficient (ECC) and normalized correlation coefficient (NCC). We also applied coherence index (CI) to evaluate the accuracy of fiber tractography in corpus callosum. In conclusion, the proposed BCP index is also capable in revealing the difference between four coregistration functions which is consistent with the results from CI index whereas the similarity of fiber tracking using NCC correction method is higher than ECC, MI and NMI.


Crossing Fibers & Non-Tensor Approaches

Hall D                                   Wednesday 13:30-15:30                                                                                                                                       

13:30         3320.     Fibre Orientation Probability Maps from Q-Ball and the Model-Based Bootstrap – A Potential Segmentation Tool

Computer 33

Hamied Ahmad Haroon1, Karl V. Embleton1, Geoff J M Parker1

1The University of Manchester, Manchester, UK

Model-based residual (MBR) bootstrap enables quantification of the uncertainty in the inferred fibre orientation for probabilistic fibre tracking using a single HARDI dataset. Here we present probability maps of observing n fibre orientations estimated by MBR bootstrapping over i iterations in every voxel. These maps provide information for the classification of tissues based on their microstructural orientation complexity. The probability of finding any given configuration reflects the underlying tissue microscopic complexity, macroscopic partial volume, and data noise levels. This information will be of use in probabilistic tractography and in monitoring changes in tissue complexity due to disease or developmental processes.


14:00         3321.     4th Order Diffusion Tensor Estimation and Application

Computer 33

Aurobrata Ghosh1, Maxime Descoteaux1, Rachid Deriche1

1INRIA, Sophia Antipolis – Méditerranée, Sophia Antipolis, France

We review and compare the existing methods for 4th order diffusion tensor imaging. We also propose an extension to the Riemannian framework developed for classical 2nd order DTI to the space of 4th order tensors. We test the methods on synthetic HARDI data, and on real brain data. In conclusion our experiments confirm that our Riemannian extension is capable of detecting fiber crossings, is the only algorithm that guarantees positive definite diffusion and is also computationally viable to be practicable.


14:30         3322.     Denoising HARDI Coefficients Using Spherical Wavelet Lifting

Computer 33

Sofia Olhede1, Brandon Whitcher2

1University College London, London, UK; 2GlaxoSmithKline, London, UK

We propose to estimate the diffusion distribution at each voxel by using a discrete wavelet transformation on the sphere, combined with an estimation procedure that is adapted to the Rician distribution.  To respect the underlying sampling scheme and avoid smoothing out details in Q-space we construct a discrete wavelet transform using lifting.


15:00         3323.     How Fast Can PAS Go?

Computer 33

Ken Earl Sakaie1

1The Cleveland Clinic, Cleveland, Ohio, USA

High angular resolution diffusion imaging, combined with advanced postprocessing methods, can resolve crossing fibers. Of the large number of postprocessing methods, Persistent Angular Structure (PAS) has desirable properties in terms of angular resolution, accuracy, and robustness against noise, but the publicly available PAS calculation software can require weeks to months to analyze a typical brain dataset on a single processor. We show that coding the PAS calculation using widely available nonlinear optimization code can speed up the computation considerably, making this powerful method an option for more widespread use.


13:30         3324.     Bootstrap Methods for Estimating Uncertainty in Constrained Spherical Deconvolution Fiber Orientations

Computer 34

Ben Jeurissen1, Alexander Leemans2, J-Donald Tournier3,4, Jan Sijbers1

1University of Antwerp, Antwerp, Belgium; 2School of Psychology, Cardiff University, Cardiff, UK; 3Brain Research Institute, Melbourne, Australia; 4University of Melbourne, Melbourne, Australia

Monte Carlo simulations were used to assess the accuracy and precision of bootstrap estimates of the uncertainty associated with brain white matter fiber orientations derived from diffusion weighted MRI using the new high angular reconstruction technique called constrained spherical deconvolution (CSD). We studied the accuracy and precision of these estimates as a function of repeated acquisitions, bootstrap realizations and inter-fiber angle. We showed an improvement of the accuracy of the uncertainty estimates of CSD fiber orientations, using an adaptation of the bootstrap called bootknife. Estimation of uncertainty is very important when fiber orientations are used in white matter fiber tractography, since errors are known to propagate.


14:00         3325.     CSF Partial Volume Effect for Diffusional Kurtosis Imaging

Computer 34

Caixia Hu1, Jens H. Jensen1, Maria Fatima Falangola1, Joseph A. Helpern1

1Center for Biomedical Imaging, New York, New York, USA

It is well known that CSF partial volume effects affect the fractional anisotropy (FA) and mean diffusivity (MD) values measured with diffusion tensor imaging (DTI).  Prior studies have shown how to assess this quantitatively by comparing results from conventional DTI with those from fluid-attenuated inversion recovery (FLAIR) DTI In this study, we applied a recent generalization of DTI called diffusional kurtosis imaging (DKI) to obtain measurements of FA, MD, and mean kurtosis (MK) in human brain with and without FLAIR and found MK to be a more robust measurement with regard to CSF contamination than either MD or FA.


14:30         3326.     Voxel Based Topometry of the ADC Profiles: Collapsing of the Dimensionality

Computer 34

Oleg Petrovich Posnansky1, Nadim Jon Shah1

1Institute of Neurosciences and Biophysics (Medicine), Research Centre Juelich, Juelich, Germany

We explore the complex geometry of the apparent diffusion coefficient (ADC) profiles and introduce a set of measures and their topological characteristics – non-integer dimensions. Using the step-by-step scale blowing sphere method we analyse the random spatial structure of the ADC profiles and present maps of indices obtained by the proposed algorithm. The maps correlate with the anatomical structure of the brain to different extents and provide more detail non-Gaussian information about brain architecture.


15:00         3327.     A Simple Method for ODF Reorientation After Deformable Imaging Registraton

Computer 34

Jinsuh Kim1, Madhura Ingalhalikar2, Vincent A. Magnotta2, Andrew L. Alexander3

1University of Iowa, Iowa City, Iowa, USA; 2University of Iowa, USA; 3University of Wisconsin, Madison, Wisconsin, USA

We propose a simple and efficient method of orientation distribution function reorientation that allows correct estimation of fiber distribution by deforming high angular resolution diffusion imaging data and applied diffusion gradient direction based on the high dimensional transformation.


13:30         3328.     Comparison of Directional Diffusion Kurtoses and Diffusivities in EAE- Induced Spinal Cord

Computer 35

Matthew Man Hin Cheung1,2, Edward Sai Kam Hui1, Wutian Wu1, Ed X. Wu1

1The University of Hong Kong, Pokfulam, Hong Kong

Understanding the complex pathology of MS is important in treatment strategies. In this experiment, diffusion kurtosis imaging (DKI) was applied to ex-vivo EAE rat spinal cord samples. The DK tensor and directional kurtoses were computed. The differences between the EAE and the normal were evaluated. The directional kurtosis analysis was shown to possess high sensitivity, thus potentially capable of better differentiating MS pathology and understanding the disease.


14:00         3329.     Diffusional Kurtosis Approximation of the Orientation Distribution Function in the Human Brain

Computer 35

Mariana Lazar1, Jens H. Jensen1, Joseph A. Helpern1

1New York University School of Medicine, New York, USA

The Orientation Distribution Function (ODF) is used to describe the directionality of multimodal diffusion in regions with complex fiber architecture. Here, we present an approximation for the ODF of water diffusion from diffusional kurtosis imaging (DKI). The DKI-based ODF approximation is decomposed into two components representing the Gaussian and non-Gaussian (NG) diffusion contributions, respectively. Orientation maps obtained for in-vivo brain imaging data demonstrate multiple fiber components in brain regions with complex anatomy, with the NG-ODF being the most sensitive to profiling the fibers’ directions. The results appear to be in agreement with known white matter architecture.


14:30         3330.     Simulation Study of Kurtosis Measurements in MR Diffusion Kurtosis Imaging

Computer 35

Kyle Ho Yiu Cheng1,2, Ed X. Wu1

1The University of Hong Kong, Pokfulam, Hong Kong

Monte Carlo simulation was performed in 1D space to study the spin diffusion, kurtosis characteristics, spin dephasing and MR signal attenuation in compartment-restricted diffusion environment. The apparent kurtosis was computed based on DKI formulation and compared to the true kurtosis and calculated from the actual diffusion displacement profiles. The simple results revealed that errors can be present in estimating true diffusion kurtosis by the apparent kurtosis. Choices of diffusion weighting parameters affect the outcomes. Both apparent diffusion kurtosis measurement and true diffusion kurtosis are not entirely intrinsic to the tissue structures because they also depend on the MR parameters.  Therefore, cautions must be taken in the quantitative interpretation of kurtosis measurements in DKI experiments.


15:00         3331.     Diffusion Kurtosis Imaging (DKI) of in Vivo Human Brain at 7 T

Computer 35

Eric Edward Sigmund1, Caixia Hu1, Mariana Lazar1, Maria Fatima Falangola1, Jens H. Jensen1, Joseph A. Helpern1

1New York University, New York, New York, USA

Diffusion kurtosis imaging (DKI) has been performed in healthy volunteer in vivo brain in a 7 T scanner and 24-channel head coil.  DKI  provides all of the information in DTI in addition to higher order structural contrast determined by non-Gaussian diffusion.  High parallel imaging factors were used to  mitigate high field EPI image artifacts.  Mean diffusivity MD, fractional anisotropy FA, and mean kurtosis MK were consistent with results at 3 T.  MD showed comparable white matter / gray matter values, FA was elevated in WM and negligible in GM, and MK was nonzero and distinct in both tissue types.



Restricted Diffusion

Hall D                                   Wednesday 13:30-15:30                                                                                                                                       

13:30         3332.     A Statistical Approach for Creating Anisotropy Maps of the Brain Using Q-Space Diffusion Weighted Images

Computer 36

Siamak Pourabdollah-Nejad1,2, Quan Jiang1,3, Douglas C. Noll2, Guang Liang Ding1, Michael Chopp1,3

1Henry Ford Hospital, Detroit, Michigan, USA; 2University of Michigan, Ann Arbor, Michigan, USA; 3Oakland University, Rochester, Michigan, USA

In this abstract, a new method for creating anisotropy maps of the brain in introduced. In this method q-space data of the brain is acquired and as a measure of anisotropy, the deviation of the diffusion vectors from a sphere is calculated and is used for creating the new map which we have named Standard-Deviation map. Comparison of our map with other conventional maps such as the FA map shows that the new map can identify regions with crossing fibers more realistically. We have validated our method with histology and q-space MR images of a rat with traumatic brain injury.


14:00         3333.     Probing Restricted Microcompartments with Double PGSE

Computer 36

Noam Shemesh1, Yoram Cohen1

1Tel Aviv University, Tel Aviv, Israel

The double PGSE (d-PGSE) sequence was used to study water diffusion in 20ìm microtubes. Indeed we found, as predicted by a recent simulation, that a negative diffraction pattern occurs. The results of non-collinear d-PGSE (i.e. d-PGSExz or d-PGSEzx ) were found to be identical and independent of the mixing time (tm). The signal decay and the diffraction patterns of the collinear directions (i.e. d-PGSExx) depend on tm. Future work in micro scale phantoms and neuronal tissues will demonstrate whether d-PGSE can overcome some of the limitations of s-PGSE experiments.


14:30         3334.     The Dependency of the MR Indices, Observed by High B-Value Q-Space Diffusion MRS on Fiber's Orientation

Computer 36

Amnon Bar-Shir1, Yoram Cohen1

1Tel-Aviv University, Tel-Aviv, Israel

The present study examines the effect of the rotational angle, α, on the apparent diffusion coefficient, extracted from low b-values and on the root mean square displacement (rmsd) of the fast- and the slow-diffusing components extracted from high b-value q-space MR diffusion experiments performed on optic nerves. The rmsd of the slow-diffusing component exhibits the most significant dependence on α. This phenomenon was found for both mature and newborn optic nerves and for short and long diffusion times. Our findings imply that the rmsd of the slow-diffusing component is the best predictor for restriction and fiber's orientation.


15:00         3335.     in vivo High Resolution Q-Space Imaging of the Spinal Cord Injury in Nonhuman Primates [Not Available]

Computer 36

Keigo Hikishima1,2, Masaya Nakamura, Kanehiro Fujiyoshi, Masayuki Yamada,2, Kazuya Kitamura, Suketaka Momoshima, Kazuo Yagi, Norikazu Tamaoki2, Yoshiaki Toyama, Hideyuki Okano

1Keio University School of Medicine, Sinjuku, Japan; 2Central Institute for Experimental Animals, Kawasaki, Japan

q-space imaging(QSI) enables us to detect the size of microstructure quantitatively and has been used gradually. However, there is no report about in vivo QSI of the spinal cord (SC) in Nonhuman primates. To evaluate the structural changes of the injured SC in the same animal longitudinally, we performed in vivo high resolution QSI of both intact and injured spinal cords in common marmosets and confirmed the accuracy of QSI through histology. As the results, high Resolution QSI map reflected the histological changes of the injured SC and was useful for its evaluation.


13:30         3336.     A Spectral Filtering View of Diffusion Gradient Encoding

Computer 37

Andrew JM Kiruluta1

1Harvard University, Cambridge, Massachusetts, USA

Diffusion imaging gradients serve to spectrally filter the temporally evolving diffusion tensor in the spectral domain. In this formulation, the design of diffusion sensitizing gradients is reduced to the problem of adequately sampling q-space in the spectral domain and hence one of designing a suitable filter.  The practical limitations imposed by the requirement for delta function type diffusion sensitizing gradients to adequately sample q-space, can be relaxed if these impulse gradients are replaced with chirped oscillatory gradients.


14:00         3337.     A Two-Compartment Model to Accurately Characterize Extra- And Intra-Cellular Spaces in Neural Tissue with Q-Space Imaging

Computer 37

Henry H. Ong1, Felix W. Wehrli1

1University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania, USA

Knowledge of white matter (WM) intra-cellular volume fraction and mean axon diameter (ICF and MAD) would provide important insight into injury and pathology. Q-space imaging (QSI) offers potential for indirect assessment of WM architecture but is complicated by signal from both extra- and intra-cellular spaces  (ECS and ICS). Here, we use a two-compartment model to fit QSI molecular displacement distribution profiles from WM tracts in healthy mouse spinal cords to characterize the ECS and ICS. The measured ICF and MAD values showed excellent agreement with histology and demonstrate the feasibility of this method to extract non-destructively accurate WM architecture information.


Methods for Brain Arterial Spin Labelling

Hall D                                   Thursday 13:30-15:30                                                                                                                                           

13:30         3338.     Reliability and Reproducibility of Arterial Spin Labeling Perfusion Measures Assessed with a Multi-Center Study

Computer 30

Thomas Liu1, Christina Wierenga2, Bryon Mueller, Jiong Jiong Wang, Gary Glover, James Voyvodic, Doug Greve, Jessica Turner, Cynthia Wible, Greg Brown, Function BIRN

1UCSD Center for Functional MRI, La Jolla, California , USA; 2UCSD Dept. of Psychiatry, La Jolla, California , USA

Arterial spin labeling MRI was used to obtain whole brain cerebral blood flow measures in a sample of 11 healthy volunteers who were scanned at three different sites participating in the Function BIRN study.  There was not a significant effect of site on the cerebral blood flow measures, but there was a significant effect of subject.


14:00         3339.     Pseudo-Continuous Arterial Spin Labeling at 7T

Computer 30

Wen-Ming Luh1, Tie-Qiang Li1, Eric C. Wong2, Peter A. Bandettini1

1National Institutes of Health, Bethesda, Maryland, USA; 2University of California, San Diego, La Jolla, California , USA

Arterial spin labeling (ASL) techniques benefit from the increase in T1 at high field strength. However, the SNR improvement at high field can only be realized with an optimal tag duration which also increases with field strength. At 7T, the optimal tag duration can reach 3 and 1.3 sec for continuous and pulsed ASL, respectively.  Pseudo-continuous ASL allows for long tag duration without special hardware. However, both B1 and B0 inhomogeneity with the volume excitation coil toward the tagging location presents challenges for PCASL. Here we implemented PCASL at 7T and demonstrated these effects and a way to mitigate them.


14:30         3340.     Mapping PASL Arterial Transit Time in Normal Human Brain Using [15O]water  PET

Computer 30

Maolin Qiu1, J Wang1, H Kim1, R E. Carson1, R T. Constable1

1Yale University School of Medicine, New Haven, Connecticut, USA

Arterial transit time (ATT) in pulsed arterial spin labeling (PASL) refers to the time it takes the arterial blood to travel from the labeling site to the capillaries. It defines the earliest time data acquisition could start after IR labeling and is required for CBF quantification. ATT measurements that use the PASL sequence suffer from the low sensitivity of PASL and intravascular contamination. ATT is usually determined and used on a per-slice basis and within slice variations in ATT are not considered. The use of improper ATT values can introduce errors in CBF quantification. In this study we used CBF measured by PET to calculate the ATT on a per-voxel basis, which allows us not only to examine the in-slice ATT variability, but also to optimize the imaging parameters for PASL. More important, the ATT map, once estimated, can be used for CBF mapping in a similar PASL imaging setup, providing voxel based ATT values.


15:00         3341.     Tagging Efficiency Improvement Using Velocity-Matched Pseudo-Continuous Arterial Spin Labeling and VERSE

Computer 30

Wen-Ming Luh1, Eric C. Wong2, S Lalith Talagala1, Peter A. Bandettini1

1National Institutes of Health, Bethesda, Maryland, USA; 2University of California, San Diego, La Jolla, California , USA

Pseudo-continuous arterial spin labeling can be performed with standard commercial scanners without special hardware. Moreover, several characteristics of the RF and gradient pulses can be adjusted for optimal performance. However, changes in velocity through the cardiac cycle can compromise tagging efficiency especially during systolic phases. It is possible to improve tagging efficiency for high velocity spins by increasing RF amplitude at the cost of SAR. Fortunately, the increase in SAR can be mitigated with VERSE transformation if needed. Here we dynamically raised PCASL RF amplitude according to the measured velocity profile at labeling location with cardiac gating and VERSE modification.


13:30         3342.     Influence of Cardiac Cycle on Velocity Selective Arterial Spin Labeling

Computer 31

Wouter M. Teeuwisse1,2, Mark A. van Buchem1, Matthias J. van Osch1

1Leiden University Medical Center, Leiden, Netherlands

In velocity selective arterial spin labeling (VS-ASL), blood that flows faster than a predetermined cut-off velocity is labeled. Because blood velocity is not constant, labeling efficiency may vary over cardiac cycle. In this study, dependency of perfusion signal on cardiac cycle was investigated. VS-ASL was performed with cardiac triggering at various trigger delays. In all volunteers mean slice perfusion showed variation up to ± 20% compared to mean perfusion with trigger delay at diastole. Variation over cardiac cycle was different between subjects. When cardiac triggering is applied, a trigger delay of 300 ms gives highest label efficiency in most cases.


14:00         3343.     Achieving Late Inflow Delay in Pseudo-CASL 3D GRASE Using a Hybridized Labeling and Background Suppression Scheme

Computer 31

María A. Fernández-Seara1, Jiongjiong Wang2, David A. Feinberg3, John A. Detre2

1Center for Applied Medical Research, University of Navarra, Pamplona, Spain; 2University of Pennsylvania Medical Center, Philadelphia, Pennsylvania, USA; 3Advanced MRI Technologies, Sebastopol, California , USA

A modified version of the pseudo-CASL background suppressed 3D GRASE sequence is presented. This sequence, which allows acquisition of perfusion maps with long post-labeling delay, in a short scan time, will be useful in cases in which arterial transit time is prolonged as occurs in cerebro-vascular disease or acute stroke.


14:30         3344.     An Efficient Labeling Scheme for CASL for Use with Multiple, Independently Switched Coils

Computer 31

Ralf Berthold Loeffler1, Ruitian Song1, Yong Zhang1, Adam Martin Winchell1,2, Josef Pfeuffer3, Zoltan Patay1, Claudia Maria Hillenbrand1

1St. Jude Children's Research Hospital, Memphis, Tennessee, USA; 2University of Memphis and UTHSC Joint Biomedical Engineering Program, Memphis, Tennessee, USA; 3Siemens Medical Solutions, Erlangen, Germany

A new paradigm for efficient multi-coil continuous arterial spin labeling is presented. The paradigm utilizes signal from every excitation to calculate the contribution of a particular artery. The paradigm was implemented on a standard clinical scanner for 3 label coils, which led to a paradigm length of 8. The label coils could be switched independently by a custom built RF cabinet that was controlled by the scanner. Volunteer measurements demonstrated good separation of vascular territories in the brain.


15:00         3345.     Continuous Artery-Selective Spin Labeling (CASSL) Applied to Distal Branches of Intracranial Arteries

Computer 31

Michael Helle1,2, David Norris2, Karsten Alfke1, Olav Jansen1

1Christian-Albrechts-Universität, Kiel, Germany; 2FC Donders Centre for Cognitive Neuroimaging, Nijmegen, Netherlands

We demonstrate the feasibility of CASSL to selectively label blood of individual branching intracranial arteries even in the immediate vicinity of other small vessels in-vivo. A saturation of the magnetization in non-selected vessels depends basically on the labeling gradient orientation, its rotation frequency and the distance from the labeling focus. By empirical optimization of these key parameters the labeling of small arteries with diameters of 3 mm and less,  that branch from the media and anterior cerebral arteries, mainly to A2/A3 and M2/M3 segments respectively, is demonstrated.


13:30         3346.     A Simple Model to Measure Arterial Cerebral Blood Volume by Arterial Spin Labelling

Computer 32

Roman Weso&#322;owski1, Penny A. Gowland1, Susan T. Francis1

1University of Nottingham, Nottingham, UK

A method of quantifying LL-FAIR data for arterial cerebral blood volume (CBVa) using simple correction factors is described. Monte-Carlo simulations are used to compare the results of fitting CBVa using this simplified method with the standard stepwise compartment model based on Bloch equations. We have used the new method to quantify (CBVa) from experimental LL-FAIR data acquired at 3 T during a 4.8 s visual stimulus.


14:00         3347.     A Probabilistic Approach to Model-Free Arterial Spin Labeling Perfusion Quantification

Computer 32

Michael A. Chappell1, Salima Makni1, Saad Jbabdi1, Mark W. Woolrich1

1University of Oxford, Oxford, UK

Traditional 'kinetic curve' model based methods for ASL analysis are not ideal for perfusion quantification in pathological tissue, since assumptions about healty tissue are made in the models. Recently the 'model-free' approach to ASL analysis has been demonstrated, this treats the signal as the convolution of an arterial input and redsidue function. Here we present an improved probabilistic based method for model-free ASL analysis. The advantage of this approach is that residue function shape can be determined under the constraint of temporal smoothness, without neededing to set the functional form a priori and without the regularisation aretefacts of a singular value decomposition approach. The method also includes a procdure to determine arterial feeding regions, for arterial input function assignment, based on blood arrival time information. Ultimately the method is designed to provide robust perfusion measurments from ASL data even in pathological tissue.


14:30         3348.     Post-Processing Correction for Extended Data Acquisition in Whole Brain 3D Quantitative PULSAR Imaging

Computer 32

Neville Dali Gai1, John Anthony Butman1

1National Institutes of Health, Bethesda, Maryland, USA

Here we devise a simple first-order correction scheme for extended data acquisition 3D PULSAR brain perfusion imaging. Extended data acquisition (~600ms) introduces some ambiguity in the transit time used in quantitative CBF determination. By applying an exponential correction for tagged blood decay in hybrid space, we attempt to reduce bolus dispersion effects during acquisition. Corrected values were compared with corresponding single slice imaging. CBF values in 3D slices were lower than corresponding single slice acquisition values due to blurring. However, after correction the values showed better agreement with the single slice acquisition case.


15:00         3349.     Comparison of Quantitative Perfusion 3D IR-PULSAR  with Multi-Slice 2D and Single Slice Imaging

Computer 32

Neville Dali Gai1, Sardha Lalith Talagala1, John Anthony Butman1

1National Institutes of Health, Bethesda, Maryland, USA

In this study, CBF values obtained with extended 3D data acquisition (for whole brain coverage) QUIPSSII IR-PULSAR are compared with values obtained with multi-slice 2D (MS-2D) and single slice acquisition. Excellent agreement in gray matter (GM) global average CBF values was found between the 3D and 2D-MS acquisition schemes. There was good agreement between the GM CBF values from 3D slices and corresponding single slice acquisitions. Values were slightly lower in the 3D case due to blurring. White matter CBF values were very low for all acquisition schemes due to much longer transit delays (~1.6s). Whole brain quantitative perfusion imaging with 3D PULSAR is feasible as long as the above limitations are kept in mind.


Diffusion Acquisition

Hall D                                   Thursday 13:30-15:30                                       Chairs: Chunlei Liu and Claudia A. M. Wheeler-Kingshot

13:30         3350.     Simulations of SNR Efficiency of DTI Using Parallel Imaging and RFOV Acquisition at 3 T and 7 T [Not Available]

Computer 33

Carolin Reischauer1, Robert Stefan Vorburger1, Bertram Jakob Wilm1, Thomas Jaermann1, Philipp Staempfli1, Peter Boesiger1

1ETH and University of Zurich, Zurich, Switzerland

The transition to ultra-high field strengths promises a boost in the SNR for diffusion tensor imaging. Image acquisition typically relies on single-shot EPI which is hampered by susceptibility-induced distortions and T2* related blurring, especially at high field strengths. These challenges can be quite effectively addressed by partial Fourier and reduced FOV acquisition, as well as parallel imaging methods. In the present work simulations at 3 T and 7 T were performed to investigate under which conditions the SNR gain can be tapped, provided that higher reduction factors have to be applied at ultra-high field strengths.


14:00         3351.     Apparent Diffusion Behaviors Modulated by Distant Dipolar Field in Solution NMR

Computer 33

Shuhui Cai1, Guiping Shen1, Congbo Cai1, Zhong Chen1

1Xiamen University, Xiamen, People's Republic of China

A modified CRAZED sequence was designed to observe and characterize apparent diffusion behaviors of signals from intermolecular double-quantum coherences during the mixing period. It is found that their apparent diffusion behaviors are different from conventional single-quantum coherences, and different orientation of diffusion weighting gradients relative to coherence selection gradients results in different apparent diffusion behaviors. This indicates that the apparent diffusion behavior is influenced by the distant dipolar field.


14:30         3352.     Optimizing Diffusion Measurements for Large-Scale Multi-Centre Trials: A Magnims DT MRI Sequence

Computer 33

Elisabetta Pagani1, Jochen G. Hirsch2, Marco Rovaris1, Achim Gass2, Petra Pouwels3, Stephan Roosendaal3, Frederik Barkhof3, Federica Agosta1, Domenico Caputo4, Antonio Giorgio5, Jacqueline Palace5, Silvia Marino6, Nicola De Stefano6, Massimo Filippi1

1Scientific Institute H San Raffaele, Milan, Italy; 2University Hospital Basel, Basel, Switzerland; 3VU University Medical Centre, Amsterdam, Netherlands; 4Scientific Institute Fondazione Don Gnocchi, Milan, Ita

The aims of the present study were: a) the development of an optimal acquisition scheme of diffusion tensor (DT) magnetic resonance imaging (MRI) for large-scale trials (considering the time issue in the context of “multi-sequence scans”) and b) the evaluation of both the feasibility of the sequence set-up on various scanners and the inter-centre reproducibility of DT-derived metrics. Twenty-nine healthy subjects were studied in 7 MRI centres using a standardized DT-MRI sequence. The inter-scanner variability of DT-derived quantities was found to be lower for anisotropy than mean diffusivity measures, especially when using 1.5 T magnets.


15:00         3353.     General-Purpose Diffusion Simulation for Any Sequence Using Monte Carlo Approach Optimized for Parallel and Multi-Core Processors

Computer 33

Donghui Yin1, Jonathan C. Sharp2, Boguslaw Tomanek2

1National Research Council Institute for Biodiagnostics, Winnipeg, Canada; 2National Research Council Institute for Biodiagnostics (West), Calgary, Canada

Our aim in this work is to extend a general-purpose integrated MR simulation / MR console environment to include diffusion-weighting using the Monte Carlo stochastic method. The general-purpose nature requires that any sequence written for the MR console is also available for simulation without additional simulation programming or expertise required of the user. We have demonstrated that the Monte Carlo method can reliably produce diffusion weighting in many cases. Our implementation has been optimized for multi-core processors so that the performance can automatically improve as industry makes new CPUs available.


13:30         3354.     Correlation Time Diffusion Coefficient Brain Mapping: Combined Effects of Magnetization Transfer and Water Micro-Kinetics on T1 Relaxation

Computer 34

Hernan Jara1

1Boston University Medical Center, Boston, Massachusetts, USA

Purpose: To develop a T1 relaxation theory incorporating the combined effects of magnetization transfer and water micro-kinetics, for the purpose of computing accurate correlation time diffusion coefficient (D(CT)) maps of structurally complex biological tissues. Methods: Images obtained with the mixed-TSE sequence were postprocessed for generating PD, T1, and T2 maps and used for computing maps of the correlation time diffusion coefficient with the developed T1-MT theory. Results: Excellent quantitative agreement is found in the brain relative to standard pulsed-field-gradient MRI. Conclusion: Magnetization transfer has a substantial effect on T1 relaxation for tissues containing a restricted pool of 1H protons.


14:00         3355.     Single-Shot Multi-Echo Parallel EPI for DTI with Improved Efficiency and Accuracy

Computer 34

Roger Nana1, Tiejun Zhao2, Xiaoping Hu1

1Georgia Institute of Technology / Emory University, Atlanta, USA; 2Siemens Medical Solutions, Malvern, USA

We introduce a multi-echo parallel EPI acquisition strategy to enhance SNR while maintaining the advantages of parallel EPI. We show that an appropriate echo combination strategy can provide significant gains in SNR as compared to using only one echo. This SNR gain can be utilized to reduce the number of measurements often required to ensure adequate SNR for accurate calculation of various DTI measures or to improve spatial resolution. Furthermore, the multiple echoes can be used to derive a T2 map, providing additional information that might be useful in some applications.


14:30         3356.     Towards Quantitative Diffusion-Weighted Chemical Shift Imaging of Brain Metabolites

Computer 34

Itamar Ronen1, Dae-Shik Kim1

1Boston University School of Medicine, Boston, Massachusetts, USA

Diffusion tensor imaging (DTI) has become a ubiquitous MRI modality for the assessment of microstructural properties of tissue. Its explanatory power, however, is limited by the lack of compartmental specificity of the water MR signal. The possibility of gaining compartment-specific diffusion information has been explored using diffusion weighted spectroscopy of intracellular metabolites. In this work we explore for the first time the feasibility of obtaining quantitative diffusion information on intracellular metabolites using diffusion weighted chemical shift imaging (CSI). The main hurdles for reliable diffusion measurements, i.e. loss of phase consistency and signal across the acquisition are addressed.


15:00         3357.     Fractional and Relative Anisotropies Are Depended on Selecting the EPI Readout Gradient Modulation Frequency at 4 Tesla MRI

Computer 34

Geon-Ho Jahng1, Michael W. Weiner2, Norbert Schuff2

1East-West Neo Medical Center, Kyung Hee University, Seoul, Republic of Korea; 2University of California,San Francisco, San Francisco, California , USA

To investigate effects of EPI readout gradient modulation frequency on the accuracy of diffusion tensor (DT)-MRI measurements, we studied the relationship between the EPI bandwidth and the Nyquist ghost for a spin echo EPI acquisition with DT preparation on a spherical water phantom and nine volunteers. In result, there were significant effects on the bandwidths for the b=800 data and for the b=0 data on the phantom study. On the human study, EPI bandwidth variations substantially corrupted diffusion anisotropy indexes. The effect can be minimized by tuning the modulation frequency of the EPI readout gradient.


13:30         3358.     Turboprop Diffusion Tensor Imaging for Computational Design of Drug Transport in Brain

Computer 35

Xiaodong Guo1, Mahadevabharath R. Somayaji2, Andreas A. Linninger2, Jia-Hong Gao1, Richard D. Penn1

1University of Chicago, Chicago, Illinois, USA; 2University of Illinois at Chicago, Chicago, Illinois, USA

Three dimensional subject-specific brain anatomy is reconstructed from Turboprop DTI images. Rigorous first principles physical transport phenomena are applied to predict the fate of a high molecular weight neurotropic factor infused into the midbrain based on DT-MRI derived drug and tissue properties. For predicting drug distribution in humans, comprehensive transport models considering heterogeneous and anisotropic brain properties derived from patient-specific images have not been adequately researched in open literature before.


14:00         3359.     Optimization of DTI Imaging Parameters Using Prior Information of Fiber Orientation

Computer 35

Wei Gao1, Hongtu Zhu, Hongyu An, Weili Lin

1University of North Carolina-Chapel Hill, Chapel Hill, USA

The aim of this study was to develop a new method for determining optimal imaging parameters for diffusion tensor imaging. The accuracy and precision of DTI experiments depend on both the choice of the imaging parameters and the noise propagation in tensor estimation process. In this work, we propose to combine both of these two processes during the optimization processes.  Additionally, information on fiber orientation distribution is also taken into account during the optimization processes.  As a result, the diffusion encoding scheme could efficiently sample those “densely oriented cone areas” in a shorter data acquisition. Thus, it leads to the efficient use of imaging acquisition time, which is crucial for pediatric imaging.


14:30         3360.     Turbo Spin Echo Diffusion Tensor Imaging (TSE-DTI) in the Brain at 3 T and 7 T

Computer 35

Eric Edward Sigmund1, Daniel Kim1, Flavio Tulio Braga1, Jian Xu2

1New York University, New York, New York, USA; 2Siemens Medical Systems, New York, New York, USA

This study used a single-shot turbo spin echo sequence for diffusion tensor imaging (TSE-DTI) in healthy volunteer brain scans in clinical scanners at 3 T and (for the first time) at 7 T, in comparison with echo-planar imaging (EPI-DTI), which suffers from known susceptibility artifacts at high field.  T2 blurring was significantly reduced in TSE images using a separate T2 map and k-space-based deconvolution procedure.  At 3 T , EPI-DTI and TSE-DTI colormaps were of comparable quality.  At 7 T and at higher resolution, EPI-DTI suffered significant image distortions, while TSE-DTI showed correct anatomical proportions and uniform white matter sensitivity.


15:00         3361.     Noise Bias Reduction and Parallel Imaging for the Measurement of Diffusion Decay

Computer 35

Guillaume Gilbert1, Georges A. Haddad1, Gilles Beaudoin1

1Centre Hospitalier de l'Université de Montréal, Montreal, Canada

In this abstract, we investigate the applicability of a noise bias reduction method for the accurate measurement of diffusion decay. This method, based on an improved combination of signals from array coils and complex averaging, is used in conjunction with standard imaging and GRAPPA parallel imaging. While some statistical noise bias correction methods developed for standard imaging are no longer exact when parallel imaging is used, this approach is shown to provide an accurate estimation of bi-exponential diffusion parameters, even when combined with GRAPPA parallel imaging.


13:30         3362.     High-Resolution Diffusion Tensor Imaging Reveals Sub-Structure Whithin Human Hippocampus in Vivo

Computer 36

David Andrew Porter1, David Atkinson2, Rod Scott2,3, Chris A. Clark2

1Siemens Medical Solutions, Camberley, UK; 2University College, London, UK; 3Great Ormond Street Hospital NHS Trust, London, UK

Diffusion tensor imaging has the potential to provide detailed information about the hippocampus that may be important in a number of diseases linked to hippocampal abnormality. However, previous human DTI studies in vivo have had difficulty in visualising hippocampal sub-structures due to the low resolution associated with single-shot EPI. This study uses the readout-segmented EPI method for high resolution DTI of the hippocampus and demonstrates some of this sub-structure in fractional anisotropy maps.


Cerebral Perfusion & Diffusion Imaging of Animal Models

Hall D                                   Thursday 13:30-15:30                                                                                                                                           

13:30         3363.     Impact of Parallel Imaging Acceleration on Perfusion Measurements of the Rodent Brain

Computer 36

David Ratering1, Christof Baltes1, Ivana Kotevic1,2, Markus Rudin1,2

1University and ETH Zurich, Zurich, Switzerland; 2University Zurich, Zurich, Switzerland

Dynamic susceptibility contrast MRI in small rodents demands for high temporal resolution to detect the fast change of the signal intensity at the first passage of the contrast agent. The feasibility of acquiring a densely sampled signal time curve using parallel imaging acceleration has been demonstrated in humans. In this work, in vivo experiments were carried out to investigate the influence of SENSE and GRAPPA acceleration on perfusion measurements of the rat brain. In addition, computer simulations were performed to test the feasibility of multi-slice imaging at reasonable temporal resolution.


14:00         3364.     Characterising the Origin of the Arterial Spin Labelling Signal in MRI Using Multi-Echo Acquisitions

Computer 36

Jack A. Wells1,2, Mark F. Lythgoe1, Mankin Choy1, David G. Gadian1, Roger J. Ordidge1, David L. Thomas1

1University College London, London, UK

We estimate the relative signals deriving from labelled spins in the vasculature and in the intra and extracellular space within the tissue, by calculating the T2 of the ASL signal at a variety of post labelling delays and tagging durations with and without bipolar crusher gradients, in the rat brain. The results provide evidence for rapid exchange and suggest that the vascular signal is comprised of both arterial and venous blood. The relative proportion of extra- to intracellular signal is ~ 2 times greater for the labelled spins in comparison to the control even at extended tagging duration (3s) and post labelling delay (0.3s).


14:30         3365.     Novel Cardiac Spin Labeling (CSL) for CBF MRI in Mice

Computer 36

Eric R. Muir1, Qiang Shen1, Timothy Q. Duong1

1Emory University, Atlanta, Georgia, USA

Continuous arterial-spin-labeling with a separate neck coil is generally more sensitive relative to the single-coil technique. Cerebral-blood-flow (CBF) MRI application in mice however has been limited by the close proximity between the neck and the brain coil, which results in saturation of the brain signals by the neck coil. We introduce an alternative approach to overcome this limitation by placing the labeling coil at the heart position, which we termed the Cardiac Spin Labeling (CSL) technique. This approach was applied to image quantitative basal blood flow and physiologically evoked blood flow changes in normal mice at high spatial resolution.


13:30         3366.     The Nuts and Bolts of Implementing a Two-Coil CASL Method for CBF Measurement on a 9.4T/30cm Scanner

Computer 37

Rongyan Zhang1, Yuan Ma1, Guangping Dai2, Kathleen Yin1, Shi-Jiang Li1

1Medical College of Wisconsin, Milwaukee, Wisconsin, USA; 2Massachusetts General Hospital, Charlestown, Massachusetts, USA

We recently implemented the two-coil CASL method on our Bruker Biospin 30cm bore 9.4T animal MRI system, and obtained excellent CBF images and time-series.  The purpose of this abstract is to share our experience, the challenges we met and present our solutions. We have found that sometimes seemingly trivial details are key to the successful implementation. It is our hope that this information can be helpful to more research and application sites to utilize this powerful technique in their fMRI studies.


14:00         3367.     Whole Brain Diffusion Tensor Image Analysis by Tract-Based Spatial Statistics (TBSS) in a Kainic Acid Rat Epilepsy Model ex Vivo

Computer 37

Kimmo K. Lehtimäki1, Teemu P. Laitinen1, Alejandra Sierra1, Jari Nissinen1, Asla Pitkänen1, Olli Gröhn1

1A.I.Virtanen Institute for Molecular Sciences, University of Kuopio, Kuopio, Finland

We implemented a whole brain voxelwise statistical analysis method, tract based spatial statistics (TBSS), into the rat epilepsy model for the comparison of ex vivo diffusion tensor data between control and kainic acid animals. Today, no reports of TBSS in the rodent brain exist. With this approach we revealed both brain regions that are known to be associated with epilepsy and those that have not been earlier connected with epileptogenesis or epilepsy. TBSS combined with animal models has great potential to serve as a robust screening method to guide tedious histological analysis to novel target areas in the brain.


14:30         3368.     Toward a Comprehensive 3D DT-MRI Atlas for Marmoset Monkey Brain

Computer 37

Hao Huang1, Xiaoqin Wang2, Madeleine Chollet2, Susumu Mori2

1UT Southwestern Medical Center, Dallas, Texas, USA; 2Johns Hopkins University, Baltimore, Maryland, USA

Marmoset has been more and more commonly used as an animal model in neurobiological study. The digital 3D comprehensive atlas for marmoset brain appears to be an urgent need. DTI can generate different contrasts of images which provide rich information of not only cortical and subcortical gray matter but also individual white matter fiber bundles. In this study, we acquired ex vivo DTI data of adult marmoset head. Important neural structures were annotated, segmented and reconstructed. The atlas is being built for the purposes of education, anatomical reference, data registration and image guided invasive surgery.


15:00         3369.     Comparing Corticocortical Interconnection Information from Tracer Studies and Probabilistic Tractography in the Postmortem Macaque Brain

Computer 37

Hamied Ahmad Haroon1, David M. Morris1, Alexander Kaiser2, Mark Augath2, Nikos K. Logothetis,12, Geoff J M Parker1

1The University of Manchester, Manchester, UK; 2Max Planck Institute for Biological Cybernetics, Tuebingen, Germany

We present a study attempting to validate the corticocortical connection information obtainable from diffusion-weighted MR data. We have implemented probabilistic tractography in data acquired in a macaque model and compared this with connection information in a database of invasive tracer studies in the same model. The nature of the corticocortical interconnection information gained from probabilistic tractography is different to that gained from invasive studies, the latter also being sparse. Our results using the LVE00a parcellation scheme indicate that probabilistic tractography is able to give statistically comparable information on corticocortical interconnections to invasive tracer studies.


13:30         3370.     Diffusion Tensor Tractography of Primate Visual Pathway [Not Available]

Computer 38

Masayuki Yamada1,2, Suketaka Momoshima3, Yoshitaka Masutani4, Kanehiro Fujiyoshi3, Keigo Hikishima,23, Osamu Abe4, Masaya Nakamura3, Shigeki Aoki4, Norikazu Tamaoki5, Hideyuki Okano3

1Fujita Health University, Toyoake, Japan; 2Central Institute for  Experimental Animals, Kawasaki, Japan; 3Keio University, Shinjuku-ku, Japan; 4University of Tokyo Hospital, Bunkyo-ku, Japan; 5Centra

We evaluated the reliability of non-human primate visual pathway depicted by diffusion tensor tractography (DTT) with the assistance of manganese-enhanced magnetic resonance imaging (MEMRI) tract tracing. The DTT depicted the typical primate retinogeniculate pathways branching bilaterally at the optic chiasm and the MEMRI tract tracing also revealed this bilateral innervation. The configurations visualized by the two modalities were nearly identical and these morphological findings were corresponded with those obtained from previous histopathological studies. Thus, the findings of our study suggested that the DTT methods play a crucial role in the morphological analysis of the non-human and/or human primate visual pathways.


14:00         3371.     Corpus Callosum Injury and Seizures in WAG/Rij Rats: Correlation Between DTI and Disease Phenotype

Computer 38

Halima Chahboune1,2, Asht Mangal Mishra1, Xenophon Papademetris1, Fahmeed Hyder1, Hal Blumenfeld1

1Yale University School of Medicine, New Haven, USA


In vivo DTI has great potential for assessing morphological changes in the CNS. Here we show alterations in morphology of neuronal pathways in a well-established animal model for human absence epilepsy. Control and epileptic rats (28-30 weeks) were studied with DTI ex vivo. We report that the tissues integrity of the corpus callosum was perturbed in epileptic rats. In conclusion, we have shown that DTI is sensitive for the detection of white matter changes in the WAG/Rij rat model of absence epilepsy.


14:30         3372.     Three Dimensional Stereotactic Atlas of Developing C57BL/6J Mouse Brains Using Diffusion Tensor Microimaging and Micro-Computed Tomography

Computer 38

Manisha Aggarwal1, Jiangyang Zhang1, Susumu Mori1,2

1Johns Hopkins University School of Medicine, Baltimore, USA; 2Kennedy Krieger Institute, Baltimore, USA

Mouse brain atlases have an important role in targeting brain structures during surgical operations in experimental mice models. A three-dimensional stereotactic surgical atlas of C57BL/6J mouse brains at six developmental stages: postnatal day 7 (P7), P14, P21, P28, P63 and P140 was developed, using high resolution diffusion tensor imaging (DTI) and micro-computed tomography (MicroCT) of mouse head specimens. DTI generated sharp white and gray matter contrasts throughout development, even in early postnatal mouse brains prior to myelination. The atlas can be used to determine the exact stereotactic coordinates of any location within the brain relative to reference skull landmarks.


15:00         3373.     Diffusion Tensor Imaging Reliably Detects Experimental Traumatic Axonal Injury and Indicates Approximate Time of Injury

Computer 38

Christine Louise Mac Donald1, Krikor Dikranian1, Sheng-Kwei Song1, Philip Bayly1, David Holtzman1, David Brody1

1Washington University, St. Louis, USA

Diffusion tensor imaging (DTI) was used to characterize the temporal changes occurring following traumatic brain injury in an experimental mouse model.  DTI signal changes correctly predicted the presence of axonal injury and quite confidently predicted the approximate timing of injury.  The results suggest that DTI could be used to assess axonal injury clinically if similar signal changes were found in humans following traumatic brain injury.


13:30         3374.     Effects of Environment Enrichment on Hypoxia-Induced Injury to Corpus Callosum and Cingulate in C57B/L6 Mice

Computer 39

Halima Chahboune1,2, Laura Ment1, William Stewart1, Douglas L. Rothman1, Fahmeed Hyder1, Micheal L. Schwartz1

1Yale University School of Medicine, New Haven, USA

Using in vivo DTI we examined morphological effects of environmental enrichment in a clinically relevant neonatal model of chronic sublethal hypoxia (CSH) injury to developing brain. Hypoxia (<10%) at the 3rd day (P3) after birth in C57B/L6 mice for a week provides an injury model which replicates neuropathologic findings that accompany preterm birth. Normal and CSH mice raised in non-enriched and enriched conditions were studied at P36 and P51. We found that enriched environment enhances tissue anisotropy within the corpus callosum and cingulate in both groups and may circumvent the delayed development observed in CSH mice.


14:00         3375.     Manganese Enhanced MR Neuronal Tract Tracing: A Passive Stochastic Process

Computer 39

Andrew Sheridan Lowe1,2, Ian D. Thompson,23, Nicola R. Sibson2

1University College London, London, UK; 2Univerisity of Oxford, Oxford, UK; 3Kings College London, London, UK

Manganese enhanced MR tract tracing is based upon the intra-cellular uptake, transportation and subsequent accumulation of manganese at terminal fields. A recent study suggests neuronal activity is blocked, while axonal transport is unaffected, by concentrations of Mn required for imaging. There remains speculation, however, regarding the relative contribution of passive diffusion as transportation rates were determined over the distal optic nerve. The current study reports the consequences of pharmacological blockade of retinal ganglion activity on remote terminal field enhancement. The paradox of blocked activity and hence expected blocked intra-cellular uptake in the context of evident terminal field enhancement is discussed.


14:30         3376.     Blood-Flow Magnetic Resonance Imaging of the Retina

Computer 39

Haiying Cheng1, Yingxia Li1, Timothy Q. Duong1

1Emory University, Atlanta, Georgia, USA

This study describes a novel MRI application to image basal blood flow, and physiologically induced blood-flow changes in the retina. Continuous arterial-spin-labeling technique with a separate neck coil for spin labeling was used to image blood flow of the rat retina at 90x90x1500-ƒÝm resolution. The average blood flow was significantly higher (6.3¡Ó1.0mL/g/min under 1% isoflurane) than the brain (1 mL/g/min). Breathing oxygen decreased blood flow 25¡Ó6% relative to baseline (air). Breathing 5%CO2 increased blood flow 16¡Ó6%. Blood-flow MRI has the potential to provide unique insights into retinal physiology and serve as an early biomarker for retinal diseases.


15:00         3377.     Cerebral Blood Flow MRI in Rats Using Cardiac Spin Labeling Technique

Computer 39

Qiang Shen1, Eric Muir1, Timothy Q. Duong1

1Emory Unviersity, Atlanta, Georgia, USA

Continuous arterial-spin-labeling with a separate neck coil is generally more sensitive relative to the single-coil technique, but the two coils need to be actively decoupled to avoid coil-to-coil electromagnetic interaction. Additionally it is difficult to measure cerebellum blood flow with the two coil technique, because the neck coil does not label the vertebral arteries which supply the cerebellum. We introduce a new approach to overcome these limitations by placing the labeling coil at the heart position. We termed this approach the <B>Cardiac Spin Labeling (CSL)</B> technique. We applied this technique to image basal CBF and physiologically evoked CBF changes in normal rats.


Fetus & Neonate: Normal, Injury, Animal, Human

Hall D                                   Monday 14:00-16:00                                                                                                                                             

14:00         3378.     Multi-Spectral Analysis of Relaxation Time Maps on Fetal Baboon Brains

Computer 38

Feng Liu1,2, Marianne Garland1, Yunsuo Duan1,2, Raymond Stark1, Bradley Peterson1,2, Alayar Kangarlu1,2

1Columbia University Medical Center, New York, New York, USA; 2New York State Psychiatric Institute, New York, New York, USA

Relaxation times T1 and T2 are sensitive to the rapid changes in the brain tissues during early life. We acquired sequential measurements of T1 and T2 in fetal baboon brains at different gestational ages. Either T1 maps or T2 maps provided better contrast than the relaxation time weighted images. Nevertheless, we used both relaxation time maps to extract multi-spectral maps as a quantitative diagnostic tool for differentiation of immature brain tissues. Both prenatal and postnatal data are presented to demonstrate the sensitivity of this tool to the process of early brain development.


14:30         3379.     Distinguishing Primary from Non-Primary Visual Cortical Areas by DTI at Early Stages of Brain Development

Computer 38

Christopher D. Kroenke1, Erin N. Taber1, Andrew K. Knutsen2, Philip V. Bayly2

1Oregon Health & Science University, Portland, Oregon, USA; 2Washington University, St. Louis, Missouri, USA

Water diffusion anisotropy is observable within the developing cerebral cortex, and becomes diminished with axonal/dendritic differentiation.  Here we report cortical diffusion anisotropy measurements in post-mortem, early postnatal ferret brain (developmentally equivalent to mid/late gestational primate brain).  Cortical surface modeling procedures are used to define visual area boundaries in brains from several stages of development.  Differences in cortical diffusion anisotropy are found between primary and non-primary areas, reflecting differences in histological structure, or rate of development.  These findings buttress prior observations in non-human primate brain tissue, and suggest that DTI can be of utility for delineating boundaries between functional cortical areas.


15:00         3380.     DTI Studies with Immunohistological Correlation in the Developing Human Frontal Cerebrum

Computer 38

Rakesh Kumar Gupta1, Richa Trivedi1, Nuzhat Husain2, Sona Saksena2, Savita Srivastava2, Mandakini Pradhan1, Vinita Das2, Gyanendra K. Malik2, Ram Kishore Singh Rathore3

1Sanjay Gandhi Postgraduate Institute of Medical Sciences, Lucknow, India; 2CSMM University, Lucknow, India; 3Indian Institute of Technology, Kanpur, India

In-vivo DTI was performed on freshly aborted 43 human fetuses with GA of 15–37 weeks. Out of them immunohistochemical analysis by using glial fibrillary acid protein (GFAP), and neuron specific enolase (NSE) antibodies was performed on 35 fetuses. Regions of interest were placed on cortical, subplate, intermediate and germinal matrix zone of frontal lobe. Peak value of cortical fractional anisotropy (FA) and maximal expression of GFAP was observed in frontal cortex of 26 weeks of GA fetus. Significant correlation was observed between FA in germinal metrics and number of NSE positive cells present in the germinal matrix zone. The ability to noninvasively monitor neuronal migration and maturation processes in vivo should greatly improve our understanding of the normal developmental pattern of the cerebrum in human fetal brain.


 15:30         3381.     Diffusion Tensor Imaging (DTI) of the Developing Human Cerebellar Cortex with Immunohistological Correlation

Computer 38

Nuzhat Husain1, Sona Saksena2, Savita Srivastava1, Richa Trivedi2, Vinita Das1, Mandakini Pradhan2, Ankur Purwar3, Gyanendra K. Malik1, Ram Kishore Singh Rathore3, Rakesh K. Gupta2

1CSMM University, Lucknow, India; 2Sanjay Gandhi Postgraduate Institute of Medical Sciences, Lucknow, India; 3Indian Institute of Technology, Kanpur, India

DTI was performed on spontaneous abortion or intrauterine dead human fetuses (n=28) with gestational age (GA) of 20-37 weeks. Fractional anisotropy (FA) values were quantified on the cerebellar cortical regions. Immuohistochemistry using Glial Fibrillary Acid Protein (GFAP) antibody was also performed on fetal brains (n=22) ranging from 20-36 weeks GA. The observed increase in cortical FA values during the early third trimester appears to be associated with the radial organization of granule cell neurons seen on GFAP stained Bergmann glial fibers. This study demonstrates the migrational and maturation changes in the developing cerebellar cortex using DTI and its confirming on GFAP immunostaining.


14:00         3382.     Diffusion Tensor Imaging and Immunohistochemical Studies in the Developing Human Cerebellar Peduncles

Computer 39

Rakesh K. Gupta1, Sona Saksena1, Nuzhat Husain2, Savita Srivastava2, Richa Trivedi1, Vinita Das2, Mandakini Pradhan1, Ankur Purwar3, Gyanendra K. Malik2, RKS Rathore3

1Sanjay Gandhi Postgraduate Institute of Medical Sciences, Lucknow, India; 2CSMM University, Lucknow, India; 3Indian Institute of Technology, Kanpur, India

Diffusion tensor imaging was performed on spontaneous abortion or intrauterine dead human fetuses (n=23) with gestational age (GA) of 20-37 weeks. Fractional anisotropy (FA) values were quantified on the middle cerebellar peduncles (MCP). Immunohistochemistry using anti-Myelin Basic Protein (MBP) antibody was also performed on fetal brains (n=9) ranging from 19-37 weeks GA. The observed maximum increase in FA values during the late third trimester of gestation, reaching a plateau by 37 weeks in MCP reflects myelination of axons during late third trimester which is confirmed by the expression of myelinated fibers in the MCP at 32 and 37 weeks GA. This study will provide a normative database of developing cerebellar white matter using DTI and its confirming on MBP immunostaining.


14:30         3383.     In-Vivo Subplate Development in Preterm Infants

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Latha Srinivasan1, Giuliana Durighel1, Serena J. Counsell1, Joanna M. Allsop1, Julie A. Fitzpatrick1, A David Edwards1, Mary A. Rutherford1

1Imperial College London, London, UK

Subplate is a transient neuronal layer that relays thalamic inputs to the developing cortex. In-vivo quantification of 80 T2-weighted MR images between 25 and 45 weeks showed that the subplate was maximal in length at 30 weeks, after which it decreased in length and was restricted to gyral crests.  During development the depth remained constant whereas there were regional variations in all subplate measurements. Infants with lesions had decreased depth and T2-intensity. At term age preterm infants had increased subplate depth, length and T2-intensity compared to term controls suggesting a combination of delayed and abnormal subplate maturation in preterm infants.


15:00         3384.     Corroboration of Disorganized Fetal Brain Lamination on Postmortem MR and DTI with Autopsy Findings

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Elysa Widjaja1, Susan Blaser2, Patrick Shannon3

1Hospital for Sick Children, Toronto, Canada; 2Hospital for Sick Children, Canada; 3Mount Sinai Hospital, Canada

Postmortem MR and diffusion tensor imaging in fetuses with brain malformations


15:30         3385.     Investigation of Neonate Brain Development Enabled by Tract-Oriented Quantification

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Mahnaz Maddah1, Andrea U.J. Mewes2,3, Heidelise Als2, Gloria McAnulty2, Eric L. Grimson1, Simon K. Warfield2

1Massachusetts Institute of Technology, Cambridge, Massachusetts, USA; 2Harvard Medical School and Children’s Hospital,, Boston, Massachusetts, USA; 3Charite, Berlin, Germany

Tract-based quantitative analysis reveals developmental differences that are not identified by ROI-based methods. Spatial patterns of the tract development are clearly observed once the parameters of interest are plotted along the tract arc length. Comparison across different subjects or at different time points are easily achieved by mapping the corresponding cluster centers. The proposed approach opens new possibilities for more accurate analysis of neonate brain development.


14:00         3386.     Thalamic Development in Preterm Infants During the Third Trimester

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Latha Srinivasan1, Ciara Abbott1, Serena J. Counsell1, Joanna M. Allsop1, Julie A. Fitzpatrick1, Giuliana Durighel1, A David Edwards1, Mary A. Rutherford1

1Imperial College London, London, UK

Thalamic inputs are necessary for proper development of functional cortical columnar units. Thalamic quantification in 80 T1-weighted images of preterm infants between 25 and 45 weeks postmenstrual age showed that the thalamic growth was 0.49 cm3/week. Further exploration in a group of longitudinally scanned infants confirmed that both the total thalamic volume and rate of growth were significantly reduced in the presence of significant cerebral lesions.  This combination of absolute volume reduction and failure of growth may explain the thalamic volume reductions seen in preterm infants at term equivalent age as shown by a variety of automated and manual methods.


14:00         3387.     Evidence of Thalamocortical Fibers Maturation in Early Human Brain Development Assessed by Diffusion Tensor Imaging

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Vincent Denolin1, Xavier De Tiège2, Anne Pardou3, Danielle Balériaux2, Patrick Van Bogaert2, Thierry Metens2, Alec Aeby2

1Philips Medical Systems Benelux, Brussels, Belgium; 2ULB-Hopital Erasme, Brussels, Belgium; 3ULB-Hopital Erasme, Belgium

Early studies on brain maturation with DTI were based on measurements in pre-defined regions of interest (ROI), which introduce a bias due to a priori hypotheses about the localization of maturational changes. Therefore we used a voxel-based approach, as known as statistical parametric mapping (SPM), to detect maturational changes in a population of preterm and term newborns, without prior prescription of the brain area to be analyzed. We showed that, besides regions previously identified using ROI analyses, i.e. motor and somatosensory tracts, optic radiation and corpus callosum, significant maturational changes also occur in the thalamus between 34 and 41 weeks gestational age.


14:30         3388.     Evolution of MR DTI Changes in Neonatal Rats After Mild Hypoxic-Ischemic Insult

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Jian Yang1,2, Cheng Wang Jin2, Pek Lan Khong, Gang Niu2, Ed X. Wu1

1Department of Electrical and Electronic Engineering,The University of Hong Kong, Hong Kong, People's Republic of China; 2The First Hospital of Xi'an Jiaotong University, Xi'an, People's Republic of China

7-day-old mild hypoxic-ischemic (H-I) rats (n=12) were studied at 7T with diffusion tensor imaging (DTIs) in day 1, 3 and 7 post H-I insult. The apparent diffusion coefficient (ADC), fractional anisotropy (FA) and directional diffusivities (¦Ë// and ¦Ë¡Í) values were measured in white matter (WM) and gray matter (GM) lesion and their contralateral side. In day 1, the ADC, FA and ¦Ë// values showed significant decrease in GM lesion whilst WM lesion only showed a significant ADC increase. In day 3, the significant FA decrease and ¦Ë¡Í increase were found in GM lesion. Significant ADC and ¦Ë¡Í increase, and FA decrease were observed in the ipsilateral WM. By day 7, all DTI values were not statistically different between two hemispheres. Thus DTI is a sensitive method to study the early transient GM and WM changes after mild H-I insult by probing the microstructural changes.


15:00         3389.     In-Vivo Magnetization Transfer Brain MRI of Mice with Neonatal Hypoxia-Ischemia

Computer 40

Ali Fatemi1,2, Mary Ann Wilson1, Seth A. Smith1, Susumu Mori1, Jiangyang Zhang1, Michael V. Johnston1, Michael T. McMahon1

1Johns Hopkins University, Baltimore, Maryland, USA; 2Massachusetts General Hospital, Boston, Massachusetts, USA

The objective of this study was to develop a quantitative in-vivo imaging technique for assessment of outcome in mice with perinatal brain injury. Magnetization Transfer (MT) Imaging was performed 3 weeks after a hypoxic-ischemic insult in CD-1 pups and showed decreased MTR values on the affected hemisphere as well as in the corpus callosum and internal capsule. This work is the first demonstration that perinatal brain injuries can be highlighted in mice using MT imaging.


14:00         3390.     Significance of Lactate in Patients with a Central Pattern of Hypoxic Ischemic Injury on DWI Within the First 3 Days of Life

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Bindu Setty1,2, Eva-Maria Ratai,23, Pallavi Sagar1,2, Kalpathy S. Krishnamoorthy,2, Ellen P. Grant1,2

1Massachusetts General Hospital, Boston, Massachusetts, USA; 2Harvard Medical School, Boston, Massachusetts, USA; 3Massachusetts General Hospital – A.A. Martinos Center for Biomedical Imaging , Charlestown, Massachusetts,

Eight neonates with hypoxic ischemic injury were studied within the first 3 days of life using MRI (DWI and MRS). The objective of this study was to determine, if the absence of lactate predicts good outcomes in patients with decreased diffusion in the ventrolateral thalamus.  No significant correlation was obtained between lactate ratios in the deep gray nuclei

and ADC values. In addition, there was no correlation between presence or absence of lactate and the extent of DWI abnormality or clinical outcome. In fact, 2 patients that died showed no lactate on MRS but had extensive areas of decreased diffusion.


14:30         3391.     Temporal Changes in Brain Water Diffusivity in Neonatal Meningitis

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Rakesh K. Gupta1, Richa Trivedi1, Gyanendra K. Malik2, Abhishek Yadav1, Kashi N. Prasad1, Ram KS Rathore3

1Sanjay Gandhi Postgraduate Institute of Medical Sciences, Lucknow, India; 2Chhatrapati Shahuji Maharaj Medical University, Lucknow, India; 3Indian Institute of Technology, Kanpur, India

Periventricular white matter of neonatal brain is known to be vulnerable to oxidative and hypoxic/ischemic injury secondary to neuro-infections. Serial diffusion weighted imaging (DWI) was performed on 45 neonates with meningitis at two time points: 1) at the time of diagnosis; and 2) after 3 weeks of antibiotic treatment. T1/T2 images showed abnormalities along with pseudo-normalization of apparent diffusion coefficient (ADC) values on 2nd study in those patients (29 %), who showed low ADC values with normal T2/T1 imaging on first MRI. The temporal variation of ADC in this study is suggestive of hypoxia related injury and may be responsible for long term neurological sequel in these neonates.


Optic Nerve

Hall D                                   Monday 14:00-16:00                                                                                                                                             

14:00         3392.     Axial Diffusivity in Acute and Isolated Optic Neuritis

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Robert T. Naismith1, Junqian Xu1, Abraham Snyder1, Tammie Benzinger1, Joshua Shimony1, Kathryn Trinkaus1, Anne H. Cross1, Sheng-Kwei Song1

1Washington University, Saint Louis, Missouri, USA

Diffusion Tensor Imaging was performed in 4 cases of acute and isolated optic neuritis in order to determine whether axial and radial diffusivity have a prognostic role for long-term clinical function.


14:30         3393.     Quantification of Glaucomatous Optic Atrophy Utilizing High Resolution MRI of the Optic Nerve [Not Available]

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Thorsten Alexander Bley1,2, Mathias Weigel1, Miriam Gaggl1, Robin Munk1, Mathias Langer1, Juergen Hennig1, Wolf Lagreze1

1University of Freiburg, Freiburg, Germany; 2University of Wisconsin - Madison, Madison, USA

With age and under certain pathologic conditions, such as glaucoma the diameter of the optic nerve may change. This study evaluates MRI of the retro-bulbar optic nerve as a surrogate marker for axonal atrophy in glaucoma.  3 Tesla MRI of the optic nerve in 47 patients with glaucoma depicted the optic nerve and its sheath within the full intra-orbital track with high contrast in 1.5 sec. acquisition time per slice. Imaging findings correlated well with severity of glaucoma.


15:00         3394.     HR-MRI Demonstrates Abnormalities of Motor Nerves and Extraocular Muscles in Patients with Congenital Complex Strabismus

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Yuan Feng Man1, Chang Zhen Wang1, Hong Yong Jiao1

1Tongren hospital, Beijing, People's Republic of China

In this article we use MRI to explore the abnormalities of oculomotor and extraocular muscles of congenital complex strabismus, the objective is to study the relationship of the nerve and the corresponding extraocular muscles.


Advanced Spinal Cord Imaging

Hall D                                   Monday 14:00-16:00                                                                                                                                             

14:00         3395.     Rapid and High-Resolved Diffusion Tensor Imaging of Mouse Lower Brain and Cervical Spinal Cord

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Virginie Callot1, Guillaume Duhamel1, Patrick J. Cozzone1

1Centre de Résonance Magnétique Biologique et Médicale (CRMBM) - UMR CNRS 6612, Marseille, France

Mouse diffusion tensor imaging (DTI) of both the brain and the spinal cord (SC) may reveal useful information on tissue damage consequent to inflammatory or degenerative diseases. To rapidly assess the geometrical and functional extent of the pathology, a large coverage and sufficient spatial resolution are required. Standard pulse sequences preclude obtaining such requirements as they do not allow achieving sufficient signal to noise ratio within an acceptable scan-time. In this work, we propose to use a spin-echo (SE) EPI DTI-based sequence to obtain spatially resolved (140x140x750 µm3) DTI metrics of both the cerebellum and cervical SC within 30 minutes.


14:30         3396.     Accurate Measurement of Mean Axon Diameter with Q-Space Diffusion MRI

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Henry H. Ong1, Felix W. Wehrli1

1University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania, USA

Accurate knowledge of white matter (WM) mean axon diameter (MAD) would provide important insight into injury and pathology. The signal decay at low q-values in q-space diffusion experiments, which can be modeled as a Gaussian, contains MAD information, but is complicated by signal from both extra- and intra-cellular spaces. Here, we use one- and two-compartment models to fit decay curves from WM tracts in healthy mouse spinal cords to measure MAD. The measured MAD values showed excellent agreement with histology, particularly the two-compartment fit, and demonstrate the feasibility of this method to extract accurate WM architecture information non-destructively.


15:00         3397.     Mouse Lumbar Spinal Cord Blood Flow (SCBF) Measurements by Arterial Spin Labeling

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Guillaume Duhamel1, Virginie Callot1, Frank Kober1, Patrick J. Cozzone1

1CRMBM, CNRS 6612, Faculté de Médecine, Université de la Méditerranée, Marseille, France

A recent work has demonstrated the feasibility of mouse SC blood flow (SCBF) measurement with arterial spin labeling (ASL) using a flow-sensitive alternating inversion recovery (FAIR) technique at the cervical level. Accurate measurements of SCBF within structures of the cord were obtained. The assessment of perfusion measurements at lower levels of the cord (thoracic, lumbar) is of interest for numerous disease models (contusion, ischemia…) but challenged by amplified bulk motion. The present study demonstrates the feasibility of lumbar SCBF measurement by ASL. Good image quality was achieved and cervical and lumbar SCBF values were compared.


15:30         3398.     A Diffusion and Perfusion EPI-Based MR Protocol for the Characterization of Rodent Spinal Cord Diseases

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Virginie Callot1, Guillaume Duhamel1, Frank Kober1, Patrick J. Cozzone1

1Centre de Résonance Magnétique Biologique et Médicale (CRMBM) - UMR CNRS 6612, Faculté de Médecine, Marseille, France

The purpose of this work was to give an experimental MR procedure that may be used to better characterize spinal cord (SC) diseases in which structural tissue damage and deficient blood supply are involved. Such a characterization has not been possible so far.

In this study, we propose to perform spin-echo EPI Diffusion Tensor Imaging and quantitative perfusion imaging of the mouse spinal cord, with an in-plane resolution of 133x133 µm² and a total scan-time of 90 minutes. Imaging was performed at the cervical level, where spinal cord injury, infarction or tumor may easily occur.


14:00         3399.     Short Scan-Time Diffusion Tensor Imaging of the Mouse Thoracic and Lumbar Spinal Cord Using Echo Planar Imaging

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Virginie Callot1, Guillaume Duhamel1, Yann Le Fur1, Patrick J. Cozzone1

1Centre de Résonance Magnétique Biologique et Médicale (CRMBM) - UMR CNRS 6612, Faculté de Médecine, Marseille, France

Spin-Echo (SE) EPI technique applied to mouse cervical spinal cord (SC) imaging has recently been proposed and a 3 to 4 acquisition-time gain-factor was demonstrated as compared to conventional SE. However, the application of SE-EPI technique at lower SC levels is challenged by higher field heterogeneities and motion amplitude.

The present study demonstrates that high-quality mouse SC DTI-EPI acquisitions at the thoracic and lumbar levels can be performed. A complete dataset (2 b-values, 6 encoding directions, 9 slices, 172x172x750 µm3 resolution) can be collected within 15 minutes. Moreover, by using outer volume suppression, 86x86 µm² in-plane resolutions can be achieved.


14:30         3400.     Temporal Changes in Axial and Radial Diffusivities in a Rat Model of Wallerian Degeneration in the Spinal Cord

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Jiangyang Zhang1, Melina V. Jones1, Cynthia A. Deboy1, Daniel S. Reich1, Paul N.  Hoffman1, Kazim A. Sheikh1, Susumu Mori1, Peter A.Calabresi1

1Johns Hopkins University School of Medicine, Baltimore, Maryland, USA

Diffusion tensor images of postmortem rat spinal cords were acquired after dorsal root axotomy. We found significant decreases in FA and axial diffusivity and a significant increase in radial diffusivity during the first three days after axotomy, followed by slow increase in radial diffusivity. MR findings were correlated with pathology in the dorsal column from 18 hours to 30 days after surgery. Our results suggest that axial diffusivity can detect very early axonal degeneration at different locations in the spinal cord, and the changes in radial diffusivity were complex and remain to be investigated.


15:00         3401.     High Field MRI of the Acute Stage of Cervical SCI in the Rat

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Georgeta Mihai1,2, Yvette S. Nout2, Petra Schmalbrock3, Jacqueline C. Bresnahan2, Michael S. Beattie2

1The Ohio State University , Columbus, USA; 2University of California San Francisco, San Francisco, USA; 3The Ohio State University, Columbus, USA

In this study the characterization of acute stage of cervical SCI was archived by imaging at 4.7T using a 3cm home built coil. Evolution of edema, cord swelling and hemorrhage was compared between two injured groups of animals, one that received 5% NaCl IV solution infusion and another one that received 0.9%NaCl starting at 30 minutes post injury. The eight hours continuous MRI scans revealed differences in term of injury evolution between the two groups. This work suggests that MRI can be used to monitor therapies and treatments aimed at reducing secondary injury in SCI.


15:30         3402.     Biplanar Spinal Cord MRI in MS - Depiction of Cord Pathology and Improvement of Clinical Correlations

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Katrin Weier1, Alain Thoeni1, Yvonne Naegelin1, Michael Amann1, Jochen G. Hirsch1, Hüseyin Duyar1, Ludwig Kappos1, Wolfgang Steinbrich1, Ernst-Wilhelm Radue1, Achim Gass1

1University Hospital Basel, Basel, Switzerland

Biplanar spinal cord (SC) MRI of MS patients was performed in 202 MS patients. PD and T2-w in axial and sagittal planes were employed to visualize SC pathology thoroughly. Typical pathological findings (focal lesions, extent of diffuse hyperintensity, focal or generalised atrophy) were used to categorize patients according to a new SC abnormality score. The resulting scores showed a good correlation to clinical functional scores (EDSS and FS). Improved visualization of the pathological changes and their integration in a new abnormality score may overcome difficulties in detection and aid interpretation of SC MRI results.


14:00         3403.     BOLD Signal Responses to Controlled Hypercapnia in Human Spinal Cord

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Julien Cohen-Adad1,2, Claudine Gauthier1,3, Habib Benali2, Serge Rossignol1, Richard D. Hoge3

1GRSNC, Department of Physiology, Faculty of Medicine, Université de Montréal, Montreal, Canada; 2INSERM U678, Université Pierre et Marie Curie (Paris VI), CHU Pitié-Salpêtrière, Paris, France; 3Unité de Neuroimagerie Fonc

We used hypercapnia to characterize the sensitivity of the BOLD method in human spinal cord. Results suggest that BOLD signal is highly dependent on the gross vascular anatomy of the spinal cord, limiting the sensitivity in grey matter since the precise vascular organization may vary among subjects. Moreover, negative BOLD was measured in various regions of the cord, possibly caused by blood-stealing, or by an increased in signal dephasing due to higher flow velocities in large vessels. The framework developed in this study will help future investigations aiming at characterizing the BOLD signal in the spinal cord.


14:30         3404.     Magnetization Transfer (MT) Asymmetry in Human Cervical Spinal Cord

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Man Cheuk Ng1, Jun Hua2, Peter C.M. van Zijl2, Edward S. Yang3, Hong Hu1, Keith D. Luk1, Edmund Y. Lam1

1The University of Hong Kong, Pokfulam, Hong Kong, People's Republic of China; 2Johns Hopkins University, Baltimore, USA; 3ASTRI, Science Park, Shatin, Hong Kong, People's Republic of China

Magnetization transfer (MT) effect includes the interaction between bulk water and semisolid macromolecules (conventional MT) and the chemical exchange dependent saturation transfer (CEST) effect. MT asymmetry was investigated in human cervical spinal cord at 3T using low power off-resonance RF irradiation at different frequency offsets. Our results showed that the z-spectrum in gray/white matter was asymmetrical about the water resonance frequency (P < 0.001) with more saturation effect at lower frequencies (negative frequency offset) far from water and at higher frequencies (positive offset) close to water, which were attributed mainly to the conventional MT and CEST effects respectively.


15:00         3405.     Computational MR Image Analysis for Spinal Cord Injury Studies

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Kevin Ming1,2, Rafeef Abugharbieh1, Claire F. Jones1, Andrew Yung1, Piotr Kozlowski1, Wolfram Tetzlaff1, Peter A. Cripton1

1University of British Columbia, Vancouver, Canada

We present a novel computational image analysis approach for studying and quantifying spinal cord deformations, in vivo, using magnetic resonance imaging (MRI) of rats. High field (7 Tesla) MR data is acquired and used to compute deformations of the spinal cord in its original physiological environment, for the first time, as opposed to traditional approaches in which animal spinal cords are exposed and directly subjected to a mechanical force. Image data was captured before and after a non-injurious deformation representative of that associated with mild myelopathy (pressure on the cord in vivo) were acquired using gradient echo FLASH T1-weighted sequence The proposed approach provides a new framework through which the causes, mechanisms, and tolerance parameters of sustained compression of the spinal cord and myelopathy, as well as the measures used in the study of neuroprotection and regeneration of spinal cord tissue, can be prospectively derived in a manner that ensures the bio-fidelity of the cord.


15:30         3406.     Hyper-Acute Evaluation of Spared White Matter in Mouse Model Contusion SCI Using in Vivo DTI

Computer 45

Joong Kim1, Hsiao-Fang Liang1, Sheng-Kwei Song1

1Washington University School of Medicine, St. Louis, Missouri, USA

Graded contusion spinal cord injury was generated at T9 spinal cord level of C57 BL/6 female mice. In vivo DTI was performed immediately after injury at 4.7 T magnet followed by perfusion and fixation. Spared white matter of contusion injured spinal cord was determined non-invasively using axial diffusivity thresholding.  The neurofilament and myelin basic protein positive immunohistochemistry staining was performed along with the standard silver staining to assess spared white matter content. In vivo DTI determined spared white matter showed good agreement with that determined using histology.


Spectroscopy & Computer Aided Analysis of Brain Tumor

Hall D                                   Monday 14:00-16:00                                                                                                                                             

14:00         3407.     Amide Proton Transfer (APT) Imaging of Human Brain Tumors with B0 Inhomogeneity Correction

Computer 46

Jinyuan Zhou1,2, Jaishri Blakeley1, Jun Hua1,2, Mina Kim1,2, Peter C.M. van Zijl1,2

1Johns Hopkins University, Baltimore, Maryland, USA; 2KKI, Baltimore, Maryland, USA

B0 field inhomogeneity is known to interfere with the quality of CEST-type experiments, especially for in vivo studies, such as APT imaging, because of the need to assign the water frequency in each voxel. We show here a practical six-offset scheme to acquire human brain high-SNR APT images. Eight brain tumor patients were scanned at 3T. Combined with the water frequency offset map fitted from an additional CEST spectrum, the method is able to correct for the artifacts produced by B0 field inhomogeneity on standard two-offset APT images.


14:30         3408.     Spatial Correlation of Metabolic Abnormalities in Non-Enhancing Low Grade Gliomas

Computer 46

Qian Zhao1,2, Ying Lu1, Jiqian Fang3, Wei Bian1, Sarah Nelson1, Tracy McKnight1

1University of California, San Francisco, San Francisco, USA; 2School of Public Health,Sun Yat-Sen University, Guangzhou, People's Republic of China; 3School of Public Health,,Sun Yat-Sen University, Guangzhou, People's Re

Grade 2 astrocytoma (AS) and oligodendroglioma (OD) are often similarly non-enhancing (NE) and appear although they convey different prognoses for patients.  Studies have shown a link between the spatial correlation of MRS features and growth activity in NE glioma.  We compared the magnitude and correlation of MRS metabolites in NE AS and OD. Compared with OD, the relative level of Cho and Cre throughout AS lesions was more uniform. AS were further distinguished by a negative correlation between NAA and Lac. The differences in the metabolic characteristics within the two tumor types may reflect differences in the underlying biology.


15:00         3409.     1H-MR Spectroscopy as a Cancer Biomarker for Anti-Angiogenic Treatment in Glioblastoma

Computer 46

Hei-Soog Kim1,2, Ciprian Catana2, Eva-Maria Ratai2, Wei-Ting Zhang2, Priscilla Yeo2, Meiyun Wang2, Tracy T. Batchelor2, Rakesh K. Jain2, A. Gregory Sorensen2

1Massachusetts Institute of Technology, Cambridge, Massachusetts, USA; 2Massachusetts General Hospital, Boston, Massachusetts, USA

A previous study demonstrated the efficiency of anti-angiogenic clinical trial in glioblastoma using MRI markers. However, there is a concern that the changes observed using standard MR imaging do not directly relate to tumor cell changes. This study suggests that 1H-MRS is a very promising method for assessing the response of cancerous tissue to anti-angiogenic treatment.

NAA/Cho measured in twenty patients showed no significant changes until day 28 and decreased afterwards. The tumor is likely to regress after 28-56 days, later than the enhancement changes on the MRI. One probable interpretation of our data is that signs of tumor regression appear later, while those of tumor recurrence earlier on 1H-MRS than on MRI.


15:30         3410.     Incorporation of MR Spectroscopic Imaging Into Gamma Knife Radiosurgery Treatment Planning

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Lawrence Ryner1,2, Muoi Tran3, Herve Momo-Jeufack2, Jordan Hovdebo1,2, Michael West2

1National Research Council Institute for Biodiagnostics, Winnipeg, Canada; 2University of Manitoba, Winnipeg, Canada; 3CancerCare Manitoba, Winnipeg, Canada

Infiltrative gliomas are known to extend beyond the area of contrast enhancement, however, conventional Gamma Knife treatment planning typically involves identifying the radiosurgical target volume on contrast-enhanced MR images. MRSI can show early biochemical changes useful for targeting abnormal tissue. We present further work in this area confirming the utility of MRSI in Gamma Knife treatment planning, as observed in patient MRSI datasets showing spectra from MRSI voxels (outside of and adjacent to the planned radiosurgical target volume) with abnormal choline to NAA ratios as compared to age and brain region-matched controls.


14:00         3411.     Interobserver Agreement for Cerebral Glioma Volumetrics on Conventional MR Imaging

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Gerard Thompson1, John Robert Cain1, Alan Jackson1, Samantha Jane Mills1

1University of Manchester, Manchester, UK

A number of groups have demonstrated that measurements of glioma tumour volume on magnetic resonance imaging are more valuable prognostically than simple uni- or bi-dimensional measurements such as the RECIST criteria. Such volumetric parameters will only be of value in clinical use and in further investigation if they can be reliably reproduced by different observers. This work tests for, and demonstrates, good interobserver agreement between non-expert radiologists employing a simple volumetric method on conventional MR imaging of cerebral gliomas.


14:30         3412.     Towards Predicting Neoplastic Recurrence with Multi-Parametric MR [Not Available]

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Evangelia I. Zacharaki1, Ragini Verma2, Sanjeev Chawla2, Elias R. Melhem2, Ronald Wolf2, Christos Davatzikos2

1University of Pennsylvania , Philadelphia, Pennsylvania, USA; 2University of Pennsylvania, Philadelphia, Pennsylvania, USA

Treatment of brain neoplasms can greatly benefit from knowledge of the extent and degree of neoplastic infiltration. The current work is a preliminary study aiming to illustrate how the integration of multiple MRI parameters via sophisticated nonlinear pattern classification methods could be applied to predict possible neoplastic progression. The method incorporates high dimensional intensity features created from multiple MRI acquisition protocols (structural MRI as well as DTI) into a pattern classification framework, to obtain a voxel-wise probabilistic spatial map that reflects the likelihood of a region presenting neoplastic recurrence after resection.


15:00         3413.     Qualitative and Quantitative Tumour Edge Characteristics for the Assessment of Glioma on Conventional MRI – Interobserver Agreement

Computer 47

John Robert Cain1, Gerard Thompson1, Alan Jackson1, Samantha Jane Mills1

1University of Manchester, Manchester, UK

Tumour border sharpness coefficient (TBSC), and subjective qualitative measures such as descriptors of tumour margins have both shown potential in differentiating between histological and genetic subtypes of glioma. These techniques will only be of use if they are reproducible in the clinical setting. This study demonstrates excellent interobserver reproducibility for TBSC in tumours of all grades. Only T2W border descriptors showed poor reproducibility in grade IV tumours and may reflect the location of these tumour and their oedema to cortical and ventricular margins. All other qualitative descriptors demonstrated acceptable reproducibility in both low and high grade tumours.


15:30         3414.     Computer-Aided Detection of Metastatic Brain Tumors Using Automated 3-D Template Matching

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Robert Ambrosini1, Peng Wang2, Balasubramanya Kolar1, Walter O'Dell1

1University of Rochester, Rochester, USA; 2University of Michigan, Ann Arbor, USA

Although screening for brain metastases using MR imaging is a critical component of the medical care for cancer patients, reading these images is both a time-consuming and subjective process when performed without computer assistance.  We have developed an automated detection algorithm for brain metastases that is based upon 3-D template matching.  The data collected on 22 patient datasets (1320 coronal MR slices) containing 161 total brain metastases show that we can achieve currently a sensitivity of 87.6% with a false positive rate of 0.58 per image slice.  These results demonstrate our algorithm’s value as a clinical assist tool for radiologists.


14:00         3415.     Nosologic Imaging of the Brain: Combined MRI and MRSI Segmentation and Classification

Computer 48

Jan Luts1, Albert J. Idema2, Arend Heerschap2, Dirk Vandermeulen1, Johan Suykens3, Sabine Van Huffel3

1Katholieke Universiteit Leuven, Leuven , Belgium; 2University of Nijmegen, University Medical Center, Nijmegen, Netherlands; 3Katholieke Universiteit Leuven, Leuven, Belgium

In this study advanced methods from image processing and pattern recognition are applied to segment and classify brain tumours, thereby including spatial information. Both MRSI and MRI data are combined to produce higher resolution nosologic images. Furthermore, class probabilities are calculated for the segmented tumour region. A leave-one-patient-out evaluation procedure is performed. The segmentation and classification scheme are applied to patients with grade II glioma tumours, grade III glioma tumours, glioblastomas or meningiomas. The proposed method offers a new way to produce nosologic images, representing tumour heterogeneity and class probabilities, which may help clinicians in decision making.