Electronic Posters : Other
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MRS Applied Methodology

Monday May 9th
Exhibition Hall  14:00 - 16:00 Computer 40

14:00 3416.   Comparing MEGA-SPECIAL to MEGA-STEAM for Pure GABA Detection at 7T 

He Zhu1,2, Richard Edden1,2, Ronald Ouwerkerk3, and Peter B. Barker1,2
1Radiology, Johns Hopkins University, Baltimore, Maryland, United States, 2F.M. Kirby Research Center, Kennedy Krieger Institute, Baltimore, Maryland, United States,3NIDDK, National Institute of Health, Bethesda, Maryland, United States

γ-aminobutyric acid (GABA) is the most abundant inhibitory neurotransmitter. In vivo detection of GABA with Magnetic Resonance Spectroscopy (MRS) is a major topic in clinical neuroscience research. In this abstract, a MEGA-SPECIAL sequence was implemented and compared to MEGA-STEAM on a 7T whole body scanner to acquire edited GABA spectra without macromolecule contamination. This technique has good sensitivity and can be used to reliably measure GABA at 7T free from macromolecular contamination.

14:30 3417.   Glutamate and Glutamine spectroscopic imaging in brain tumors at 3.0 T 

Sandeep Kumar Ganji1, Ivan E Dimitrov1,2, Elizabeth A. Maher3, and Changho Choi1
1Advanced Imaging Research Center, University of Texas Southwestern Medical Center, Dallas, Texas, United States, 2Philips Medical Systems, Cleveland, Ohio, United States, 3Internal Medicine and Neurology, University of Texas Southwestern Medical Center, Dallas, Texas, United States

Alterations in glutamate (Glu) and glutamine (Gln) levels have been reported in several brain tumors ex-vivo and in vivo. Spectroscopic imaging of Glu and Gln in vivo remains challenging due to spectral overlaps and low signal intensities. Here we report Glu and Gln spectroscopic imaging employing an optimized-TE PRESS-based method. We present the in-vivo data from healthy volunteers and brain tumor patients. The concentration maps of metabolites are reported.

15:00 3418.   Thalamic and subcortical GABA in human brain at 7T 

Jullie W Pan1, Nikolai Avdievich1, and Hoby P Hetherington1
1Neurosurgery, Yale University School of Medicine, New Haven, CT, United States

For purposes of SNR, the majority of measurements of GABA have been primarily performed in superficial locations using local surface coils. However because of its potential roles in movement control and seizures, the measurement of GABA in subcortical nuclei is of significant interest for neurological studies. In these regions however significant challenges are present because of Bo shimming and the need to eliminate the macromolecule resonance. We used a transceiver array and 4th- partial 5th shim insert at 7T in the human brain to evaluate thalamic and putamen GABA in comparison to white and gray matter.

15:30 3419.   In vivo short spin-echo 1H MR spectroscopy with macromolecule suppression 

Xi Chen1,2, Laura M. Rowland2, and Yihong Yang1
1Neuroimaging Research Branch, Nation Institute on Drug Abuse, Baltimore, MD, United States, 2Maryland Psychiatric Research Center, University of Maryland School of Medicine, Baltimore, MD, United States

A broadband outer volume suppression scheme is proposed to compensate the potential subtraction error of the ISIS module in the SPECIAL sequence; an macromolecule suppression scheme is also proposed using a modified SPECIAL sequence. A similar SNR as the STEAM spectroscopy is achieved.

Tuesday May 10th
  13:30 - 15:30 Computer 40

13:30 3420.   CT-PRESS Based Spiral Spectroscopic Imaging with Robust Water and Lipid Suppression using Multiple Dualband Frequency-Selective RF Pulses 

Meng Gu1, Daniel M. Spielman1, Natalie M. Zahr2, Adolf Pfefferbaum2, Edith V. Sullivan2,3, and Dirk Mayer1,2
1Radiology, Stanford University, Stanford, California, United States, 2Neuroscience Program, SRI International, Menlo Park, California, United States, 3Psychiatry & Behavioral Sciences, Stanford University

Fast spiral spectroscopic imaging based on constant-time-point-resolved spectroscopy, CT-PRESS, has been implemented at 3T for detection of Cho, Cre, mI, Glu, Gln and NAA. To avoid losing spatial coverage from volume selection using PRESS, a robust suppression scheme using multiple dualband frequency-selective RF pulses was applied to simultaneously suppress both water and lipids of different T1s over a ± 20% range of B1 inhomogeneity. This in vivo human study demonstrated whole brain coverage with effective water and lipid suppression without disturbing signals of metabolites of interest and within an acquisition time suitable for clinical studies.

14:00 3421.   Fully adiabatic 31P 2D CSI with negligible chemical shift displacement error at 7T 

Marek Chmelik1, Stephan Gruber1, Siegfried Trattnig1, and Wolfgang Bogner1
1MR Centre of Excellence, Department of Radiology, Medical University of Vienna, Vienna, Austria

Fully adiabatic 31P 2D CSI sequence with negligible chemical shift displacement error (CSDE) for 7T based on 1D-ISIS/2D-CSI selection was developed. Slice selective excitation was achieved by a spatially selective broadband GOIA inversion pulse prior to non selective adiabatic excitation which was followed by 2D phase encoding gradients. This reduced CSDE ~8 fold in slice direction compared to conventional 2D-CSI with Sinc3 selective pulse at 7T. The sequence allows in combination with AHP or BIR-4 excitation fully adiabatic performance suitable to be used with B1 inhomogeneous surface coils.

14:30 3422.   1H SPECIAL-MRSI at Ultra-Short TE: Improved Metabolite Detection for Multiple Voxels in Human Brain at 3T 

Ralf Mekle1, Vladimir Mlynarik2, Bernadeta Walaszek1, Rolf Gruetter2,3, Bernd Ittermann1, and Florian Schubert1
1Physikalisch-Technische Bundesanstalt, Berlin, Germany, 2Laboratory for Functional and Metabolic Imaging (LIFMET), Ecole Polytechnique Federale de Lausanne, Lausanne, Switzerland, 3Departments of Radiology, Universities of Lausanne and Geneva, Lausanne and Geneva, Switzerland

The spin echo full intensity acquired localized (SPECIAL) MRS technique provides the benefits of full signal intensity at short TE resulting in enhanced metabolite quantification as previously shown in single volume studies. Since many applications require the acquisition of spectra from multiple voxels, 1H SPECIAL-MRSI was realized in this study for the first time on a clinical platform. Human brain MRSI data at very short TE were acquired for N = 5 volunteers at 3T. High spectral quality and minimization of T2 losses and J-evolution effects resulted in reliable quantification (CRLB < 20%) of several metabolites in multiple voxels.

15:00 3423.   A Semi_LASER 1H MRS Sequence Designed with High Bandwidth RF Pulses for Use at 4.0 T 

Hui Liu1,2, and Gerald B. Matson1,3
1Center for Imaging of Neurodegenerative Diseases (CIND), Veterans Affairs Medical Center, San Francisco, CA, United States, 2Northern California Institute for Research and Education, San Francisco, CA, United States, 3University of California, San Francisco, CA, United States

Although in vivo MRS at high magnetic field has the potential to better quantitate metabolites exhibiting J-coupled resonances such as glutamate, glutamine and myo-Inositol, which are all of clinical interest, the ‘four-compartment’ artifact exhibited by J-coupled resonances is exacerbated because of the increased spectral dispersion. The four-compartment artifact can be alleviated by higher RF pulse bandwidth or short echo-time acquisition. However, short echo-time sequences such as STEAM acquires only half of the S/N, while the SPECIAL sequence is susceptible to motion artifacts due to its subtraction scheme. The LASER sequence can be used with higher RF bandwidth pulses; however, its relatively high SAR hinders its use. In this study, a single voxel semi-LASER localization scheme suitable for use on commercial MRI instruments was implemented at 4T at a relatively long echo time (57 ms) with new, high bandwidth RF pulses, designed by our optimization routine incorporated into MatPulse. The higher bandwidth RF pulses combined with the semi-LASER localization scheme helped to suppress the four-compartment artifact, and enabled J-coupled resonances to be acquired with relatively high S/N at the relatively long TE time of 57 ms without major baseline artifacts.

Wednesday May 11th
  13:30 - 15:30 Computer 40

13:30 3424.   Absolute Metabolite Quantification by Magnetic Resonance Spectroscopy Imaging in Skeletal Muscle: First Results and Reproducibility 

Xin Wang1, Laura Fayad1, and Peter Barker2
1Johns Hopkins University, Baltimore, Maryland, United States, 2Radiology, Johns Hopkins University, United States

The purpose of this study is to report and verify the reproducibility of multi-voxel 2D magnetic resonance spectroscopy imaging (MRSI) for the absolute metabolite quantification in the musculoskeletal system. The phantom replacement method was employed for the absolute quantification of Choline in 5 healthy skeletal muscle groups. Good agreement was achieved for the estimation of Cho concentration in different muscle groups and between different scanning sessions at 2 months apart. MRSI is a promising technique for the metabolic evaluation of musculoskeletal physiology and pathology, by providing large field of view imaging at a high spatial resolution.

14:00 3425.   In Vivo Phosphorus MR Spectroscopy Demonstrates the Heterogeneous Composition of Sarcomas 

Fernando Arias-Mendoza1, and Truman R. Brown1
1Radiology, Columbia University Medical Center, New York, NY, United States

Proper spectral and spatial analysis of 3D localized 31P MRS acquired from the tumor masses of 20 sarcoma patients was performed. The analysis helped stand out the diverse metabolic characteristics of the sarcoma masses due to their heterogeneity improving their correlation with malignant behavior and thus outcome to treatment and survival.

14:30 3426.   In Vivo MR Spectroscopy of Irregularly Shaped Single Voxel Using 2D-Selective RF Excitations Based on a PROPELLER Trajectory 

Martin G. Busch1,2, and Jürgen Finsterbusch1,2
1Department of Systems Neuroscience, University Medical Center Hamburg-Eppendorf, Hamburg, Germany, 2Neuroimage Nord, University Medical Centers Hamburg-Kiel-Lübeck, Hamburg-Kiel-Lübeck, Germany

Conventional single-voxel localization based on cross-sectional RF excitations suffers from partial volume effects if the target volume is not cuboidal. 2D-selective RF (2DRF) excitations are able to define an arbitrary excitation profile within a plane and can be used to adapt the voxel shape to the target. This is demonstrated in vivo in the human brain for 2DRF excitations based on a PROPELLER trajectory which allow obtaining high-resolution profiles at echo times of 30 ms. Compared to a previous in vivo study, the SNR efficiency is considerable improved because the excitation k-space centre is covered with each shot.

15:00 3427.   Correlated Spectroscopic Imaging Using Concentrically Circular Echo-Planar Trajectories in Human Calf 

Neil Wilson1, Jon Furuyama1, and Michael Albert Thomas1
1Radiology, UCLA, Los Angeles, CA, United States

A correlated spectroscopic imaging sequence that traces a circular k-space trajectory is proposed. When using sinusoidal gradients, higher spectral bandwidths can be achieved due to the reduced hardware demands compared to those for trapezoidal gradients. This is crucial for spectroscopic imaging at higher field strengths where higher spectral bandwidth is required to avoid aliasing. Also, less phase encoding steps are needed than for a traditional echo-planar readout, shortening scan times. A human calf was scanned on a Siemens 3T Trio in under 11 min, and 2D spectra from the soleus, tibialis anterior, and marrow are presented.

Thursday May 12th
  13:30 - 15:30 Computer 40

13:30 3428.   Sensitivity and Localization Reliability Analysis for Spectral Localization by Multichannel Coils 

Li An1, Steven Warach1, and Jun Shen2
1National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, United States, 2National Institute of Mental Health, National Institutes of Health, Bethesda, MD, United States

A spectral localization technique for in vivo magnetic resonance spectroscopy using a multichannel receiver coil has been previously reported. The proposed technique allows a few compartmental spectra to be reconstructed from multichannel data acquired with no or very few phase encoding steps. In this work, a sensitivity parameter, a spatial response function (SRF), and a localization parameter were defined to compare the sensitivity and localization reliability between the proposed technique and SLIM (spectral localization by imaging). Phantom experiments showed that the proposed technique had higher sensitivity and localization reliability compared to SLIM.

14:00 3429.   Accelerating Magnetic Resonance Spectroscopy Imaging by Compressed Sensing 

Peng Cao1,2, Condon Lau1,2, and Ed X. Wu1,2
1Laboratory of Biomedical Imaging and Signal Processing, The University of Hong Kong, Hong Kong SAR, China, People's Republic of, 2Department of Electrical and Electronic Engineering, The University of Hong Kong, Hong Kong SAR, China, People's Republic of

This study aimed to apply compressed sensing in 2D proton MRSI. Both phantom and in vivo rodent brain MRSI experiments were performed on a 7T Bruker scanner with compressed sensing reconstruction. Results showed that the proposed method could yield high resolution MRSI without loss of spectral accuracy with a large understanding factor (30%).

14:30 3430.   Combination of Compressed Sensing and SENSE for 1H MRSI: An Initial Result 

Zhengchao Dong1,2, Yudong Zhang1,2, and Bradley S Peterson1,2
1Columbia University, New York, NY, United States, 2New York State Psychiatric Institute, New York, NY, United States

In recent years, the combination of compressed sensing MRI and SENSE has been reported to achieve higher acceleration rates than either of them can individually and thereby, significantly reduce scan times. In this work, we proposed a highly accelerated proton MRSI technique by combining SENSE and CS.

15:00 3431.   Non-negative blind source separation techniques for describing intratumoral histopathological tissue properties within MRSI measurements 

Anca Ramona Croitor Sava1, Sofie Van Cauter2, Diana Maria Sima1, Maria Osorio Garcia1, Uwe Himmelreich2, and Sabine Van Huffel2
1Depart. Electrical Eng. – ESAT/SCD, Katholieke Universiteit Leuven, Leuven, Belgium, 2Dept. Medical Diagnostic Sciences – Biomedical NMR Unit, Katholieke Universiteit Leuven, Leuven, Belgium

The accuracy of Magnetic resonance spectroscopic imaging in differentiating and grading brain tumors is limited by significant variability of in vivo spectra as an effect of intra-tumoral heterogeneity. We propose a first screening between these intratumoral histopathological tissue properties, such as viable tumor cells, necrotic tissue or regions where the tumor infiltrates normal by quantifying their abundance within each MRSI voxel using a non-negative matrix factorization algorithm. Additionally, nosologic images are drawn based on the extracted abundance maps, reflecting the presence of necrosis, viable tumor cells or infiltrations in the MRSI grid.

Electronic Posters : Other
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Spectroscopic Quantitation

Monday May 9th
Exhibition Hall  14:00 - 16:00 Computer 41

14:00 3432.   Quantitative Musculoskeletal MRS Using the Phantom Replacement Method and Phased-array Receiver Coils 

Xin Wang1, Laura Fayad2, and Peter Barker3
1Radiology, Johns Hopkins University, Baltimore, Maryland, United States, 2Johns Hopkins University, United States, 3Johns Hopkins University, Baltimore, Maryland, United States

The purpose of this study was to compare two different quantitation methods for musculoskeletal (MSK) MRS using phased array coils. The phantom replacement and internal water-referencing methods were compared for determining Choline (Cho) absolute concentration in normal skeletal muscle at 3T. In vivo Cho concentrations were measured by single voxel proton MRS in the quadriceps muscle of eleven volunteers. Excellent agreement between the two techniques was found on testing phantoms, while some discrepancies were observed in vivo.

14:30 3433.   Proton Magnetic Resonance Spectroscopy Method for the Detection of Human Brain Metabolites at 7 Tesla 

mohammed Elywa1, Samir Mulla-Osman1, Martin Walter2, Kai Zhong1, Frank Godenschweger1, Oleksandr Khorkhordin1, Jörn Kaufmann3, and Oliver Speck1
1Department of Biomedical Magnetic Resonance, Otto-von-Guericke-University, Magdeburg, Germany, 2Universitätsklinik für Psychiatrie, Otto-von-Guericke-University, Magdeburg, Germany, 3Department of Neurology, Otto-von-Guericke-University, Magdeburg, Germany

The minimal voxel size that can be measured with high spectral quality is 1.7 mL and many metabolites can be reliably detected. The results provide a powerful non-invasive tool for routine proton magnetic resonance spectroscopy of the human brain at high magnetic field of 7T using a 24 channel volume head coil and a combination of RF-sequence (STEAM-VERSE), automatic 3D shim,and single volume spectroscopy localization technique.

15:00 3434.   Precision and repeatability of in vivo GABA and glutamate quantification 

Ruth L O'Gorman1, Richard Edden2, Lars Michels1, James B Murdoch3, and Ernst Martin1
1University Children's Hospital, Zürich, Switzerland, 2Russell H Morgan Department of Radiology and Radiological Sciences, Johns Hopkins University, Baltimore, MD, United States, 3Toshiba Medical Research Institute, Mayfield Village, OH, United States

This study investigates the reliability of GABA and glutamate (Glu) concentrations, derived with MEGA-PRESS and quantified using three different analysis methods. The reliability and sensitivity of the GABA levels are also assessed both with and without metabolite nulling to correct for macromolecular contributions to the GABA+ peak at 3 ppm. Overall LCModel provided the best precision for both GABA and Glu. However, the uncorrected LCModel GABA values appear to overestimate the GABA concentrations, although the CRLB values for the LCModel fit were higher for the corrected spectra.

15:30 3435.   Exploring collagen self-assembly by NMR 

Natalia Lisitza1, Xudong Huang2, Hiroto Hatatu3, and Samuel Patz3
1Department of Radiology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, United States, 2Department of Psychiatry, Massachusetts General Hospital, Harvard Medical School, Boston, MA, United States, 3Department of Radiology, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA, United States

In this study we use NMR to explore collagen self-aggregation. We observe an abrupt change of the total collagen NMR signal intensity at a critical concentration where self-aggregation starts. We measure the NMR spectrum of collagen as function of protein concentration and detect changes of this dependence in time; we relate these changes to collagen aggregation. We show that the concentration dependence of the collagen NMR signal is sensitive to pH and that this behavior correlates with aggregation mechanisms proposed in literature. The advantage of NMR is that it allows noninvasive investigation of biological systems in solution, preserving their physiological conformations and functions.

Tuesday May 10th
  13:30 - 15:30 Computer 41

13:30 3436.   In-vivo Short-Echo-Time Single-Voxel Proton LASER Spectroscopy at 7 Tesla Incorporating Macromolecule Subtraction 

Jacob Penner1,2, Andrew Lim1, Andrew Curtis1,2, Martyn Klassen1, Joseph Gati1, Matthew Smith3,4, Michael Borrie3,4, and Robert Bartha1,2
1Centre for Functional and Metabolic Mapping, Robarts Research Institute, London, Ontario, Canada, 2Medical Biophysics, University of Western Ontario, London, Ontario, Canada, 3Medicine, University of Western Ontario, London, Ontario, Canada, 4Division of Aging, Rehabilitation, and Geriatric Care, Lawson Health Research Institute, London, Ontario, Canada

The purpose of this study was to develop a method for acquiring short-echo-time 1H MRS at 7T. Firstly, data was obtained from the parietal-occipital region of young healthy volunteers using a modified single-voxel LASER sequence. The inversion times TI1/TI2 for optimal metabolite suppression leading to macromolecule detection were found to be 3.14/0.70 s from measured T1’s of NAA, Glu, Cr, and Cho (1.34 ± 0.08 s, 1.04 ± 0.09 s, 1.48 ± 0.05 s, and 1.22 ± 0.05 s, respectively). Secondly, the prior knowledge used for fitting in-vivo data was developed including lineshapes from 19 separate aqueous metabolite phantoms.

14:00 3437.   Optimization of metabolite basis-sets prior to quantitation: a Quantum Mechanics approach 

Andrii Lazariev1, Abdul-Rahman Allouche2, Monique Aubert-Frécon2, Florence Fauvelle3, Karim Elbayed4, Martial Piotto4,5, Izzie Jacques Namer6, Dirk van Ormondt7, and Danielle Graveron-Demilly1
1Creatis-LRMN, Université Claude Bernard Lyon 1, Villeurbanne, France, 2LASIM, Université Claude Bernard Lyon 1, Villeurbanne, France, 3CRSSA/BCM, Grenoble, France,4Institut de Chimie, Strasbourg, France, 5Bruker BioSpin, Wissembourg, France, 6Department of Biophysics and Nuclear Medicine, University Hospitals of, Strasbourg, France, 7Delft University of Technology, Delft, Netherlands

Nowadays, medical diagnoses are often based on results obtained from HRMAS – High-Resolution Magic Angle Spinning NMR – spectroscopy. This technique enables setting up metabolite profiles of ex vivo pathological and healthy tissue. The need to monitor diseases and pharmaceutical follow-up appeal the necessity of automatic quantitation of HRMAS 1H signals. However, the values of chemical shifts of proton groups in several metabolites can slightly differ subject to the microenvironment in the tissue or cells, in particular with its pH which hampers accurate estimation of the metabolite concentrations mainly when using quantitation algorithms based on a metabolite basis-set. In this work, we propose an accurate method based on Quantum Mechanics simulations able to respect the correct fingerprints of metabolites.

14:30 3438.   Association of MRS Measures in the Brain with Body Mass 

Andrew A. Maudsley1, Varan Govind2, and Kris Arheart3
1Radiology, University of Miami, Miami, FL, United States, 2Radiology, University of Miami, 3Epidemiology, University of Miami

Analysis of volumetric 1H MRSI data in a group of 140 normal subjects reveals patterns of residual magnetic field inhomogeneity associated with body mass index (BMI). Significant associations of metabolite concentrations with BMI were also observed, although interactions between BMI, age, B0, and linewidth are also indicated. It is hypothesized that line shape distortions associated with systematic differences in B0 inhomogeneity associated with body weight may impact in vivo MRS measures. Results indicate that investigations of MRI and MRS findings with BMI should account for potential impact of magnetic field inhomogeneities.

15:00 3439.   In vivo 1H MRS quantification of Alzheimer disease in frontal hippocampus of mice with and without inversion recovery to assess the macromolecular contribution 

Maria Isabel Osorio Garcia1, Diana Sima1, Flemming Ulrich Nielsen2, Tom Dresselaers2, Uwe Himmelreich2, Fred Van Leuven3, and sabine Van Huffel1
1Electrical Engineering - ESAT/SCD, Katholieke Universiteit Leuven, Leuven, Belgium, 2Biomedical Nuclear - Magnetic Resonance Unit, Katholieke Universiteit Leuven, Leuven, Belgium, 3Experimental Genetics Group LEGTEGG, Katholieke Universiteit Leuven, Leuven, Belgium

In this work, we study the metabolite behavior of control and APP.V717I transgenic mice using 1H MRS at 9.4 T in the hippocampus. The time domain quantification method AQSES is use for estimating the metabolite contributions which is able to estimate the background modeling using splines and particularly, individual macromolecular signals have been acquired using inversion recovery and added to the basis set of metabolites used to fit the signals. Results obtained in this study show that there are no significant differences between control and APP mice visible in the available MRS spectra. Furthermore, variability in quantification results indicates that detection of Alzheimer disease in the studied animals using 1H MRS in the hippocampus does not provide the class separation as expected in humans.

Wednesday May 11th
  13:30 - 15:30 Computer 41

13:30 3440.   Accuracy and reproducibility of short-TE MRS measurements of GABA at 3T as a function of linewidth and SNR 

Jamie Near1, Jesper Andersson1, Philip Cowen2, and Peter Jezzard1
1FMRIB Centre, University of Oxford, Oxford, Oxfordshire, United Kingdom, 2Department of Psychiatry, University of Oxford, Oxford, Oxfordshire, United Kingdom

We investigate the accuracy and reproducibility of short-TE MRS measurements of GABA as a function of changing experimental conditions (linewidth and SNR). This is achieved by generating a large number of simulated datasets with known metabolite concentrations. Each dataset was then analysed using LCModel, and the estimated GABA concentrations were compared with the actual known values. This procedure was repeated for a range of experimental conditions, and the reproducibility and accuracy were calculated for each. Under experimental conditions corresponding to ACC and PCC, the reproducibility errors were 17% and 10%, respectively, and the estimation errors were 16% and 3%, respectively.

14:00 3441.   In Vivo T2 of GABA at 7T: measuring transverse relaxation times using edited MRS 

Jarunee Intrapiromkul1, Ying Cheng2, He Zhu1,3, Peter B Barker1,3, and Richard Anthony Edward Edden 1,3
1Russell H Morgan Department of Radiology and Radiological Science, The Johns Hopkins University, Baltimore, MD, United States, 2Department of Biomedical Engineering, The Johns Hopkins University, Baltimore, MD, United States, 3Kennedy Krieger Institute, Baltimore, MD, United States

Accurate measurement of in vivo relaxation times is necessary for quantitative in vivo magnetic resonance spectroscopy. Recent work applying edited MRS of GABA has generally quoted concentrations in institutional units or as signal ratios, in part because the in vivo relaxation times of GABA are unknown. In this abstract, we characterize the TE-dependence of edited GABA detection at 7T and show that this knowledge allows T2 to be measured (T2 = 53 ms).

14:30 3442.   Enhanced Detection of Glutamate in the Human Brain Using Very Short Echo Times 

Sarah Andrea Wijtenburg1,2, and Jack Knight-Scott1
1Radiology, Children's Healthcare of Atlanta, Atlanta, Georgia, United States, 2Biomedical Engineering, University of Virginia, Charlottesville, Virginia, United States

In this work, we examine the capability of a very short TE phase rotation STEAM (PR-STEAM) to detect glutamate. Spectrosopic data were acquired from the anterior cingulate gyrus using 6.5-ms TE PR-STEAM, 40-ms TE PRESS, 72-ms TE STEAM, and TE-Averaging with an effective TE of 105-ms on a clinical 3-T MRI system. The 6.5-ms TE PR-STEAM identified glutamate with the greatest precision (CV of 7.1%), followed by TE-Averaging (CV of 8.9%), 40-ms TE PRESS (CV of 11.9%), and 72-ms TE STEAM (CV of 13.8%). Thus, glutamate is best detected in the human brain at 3-T using very short TEs.

15:00 3443.   Novel approach for the assessment of the bioavailability of exogenous phosphate by in vivo dynamic 17O and 31P MRS and MRI 

Gheorghe D Mateescu1,2, Chris A Flask1,3, and Jeffrey L Duerk1,3
1Radiology, Case Western Reserve University, Cleveland, OH, United States, 2Chemistry, Case Western Reserve University, Cleveland, OH, United States, 3Biomedical Engineering, Case Western Reserve University, Cleveland, OH, United States

This communication presents a novel application of in vivo dynamic 17O and 31P MRS and MRI for the assessment of the bioavailability of exogenous phosphate (dietary or pharmaceutical). The method consists of administration of 17O-enriched phosphate to mice, followed by dynamic measurement of the 17O label transfer to body water, that results from the hydrolytic reactions of phosphate metabolism. Alternately, an efficient measurement could be done in 31P MR with 17O decoupling. This new approach may become important in relating phosphate homeostasis defects to metabolic or other diseases.

Thursday May 12th
  13:30 - 15:30 Computer 41

13:30 3444.   Longitudinal inter- and intra-individual human brain metabolic quantification with proton MR spectroscopy at 3T 

Ivan Kirov1, Ilena George1, Nikhil Jayawickrama1, James Babb1, Nissa Perry1, and Oded Gonen1
1Radiology, New York University, New York, NY, United States

Despite research and clinical applications, the longitudinal reproducibility of proton MR spectroscopy (1H-MRS) in the healthy human brain at high magnetic fields and over long periods is not established. We assessed the inter- and intra-subject reproducibility of 1H-MRS of an approach suited for diffuse pathologies. Ten individuals were scanned at 3T annually for three years. Spectra were acquired from 480 voxels, over 360 cc of the brain. The inter- and intra-subject coefficients of variation were on the order of 9-12% and 7-10%, respectively, demonstrating the utility of the approach for cross-sectional and longitudinal studies of diffuse neurological diseases.

14:00 3445.   If J doesn’t evolve, it won’t J-resolve: J-PRESS with bandwidth-limited refocusing pulses 

Richard Anthony Edward Edden1,2, and Peter B Barker1,2
1Russell H Morgan Department of Radiology and Radiological Science, The Johns Hopkins University, Baltimore, MD, United States, 2FM Kirby Center for Functional MRI, Kennedy Krieger Institute, Baltimore, MD, United States

There is increasing interest in the J-PRESS technique, an in vivo implementation of two-dimensional J-spectroscopy combined with PRESS localization, for high field spectroscopy studies of the human brain. The experiment is designed to resolve scalar couplings in the 2nd, indirectly detected dimension, but will only do so if the slice-selective refocusing pulses in the PRESS sequence affect all coupled spins equally. At high magnet field strengths, due to limited RF pulse bandwidth, PRESS-based localization results in spatially dependent evolution of coupling. In some regions of the localized volume, coupling evolves during the PRESS echo time, while in other regions it may be partially or fully refocused. This study investigates the impact of this effect on the appearance of the J-PRESS spectrum for coupled spins, focusing on two commonly observed metabolites, lactate and N-acetyl aspartate, showing that such behavior results in additional peaks in the J-resolved spectrum (termed J-refocused peaks). It is also demonstrated that increasing the bandwidth of refocusing pulses significantly reduces the size of such signals.

14:30 3446.   Optimal Methodology for Glutamate and Glutamine Signal Quantification with Single Voxel MRS of the Human Brain 

Jingjing Zhang1, Sulaiman Sheriff2, Andrew A Maudsley2, Karl Goodkin3, and Jeffry R Alger1
1Neurology, University of California at Los Angeles, Los Angeles, CA, United States, 2Radiology, University of Miami, Miami, FL, United States, 3Psychiatry and Behavioral Neurosciences, Cedars-Sinai Medical Center, Los Angeles, CA, United States

In our efforts to investigate whether the TE 30 PRESS or the TE-averaged acquisition method is more advantageous in detecting glutamate and glutamine for our HIV-1 associated MCMD study, we have found that the TE-averaged acquisition provides a better Gln detection than the TE 30 PRESS method, but no significant differences were found in their abilities detecting Glu and NAA.

15:00 3447.   A statistical framework for biomarker identification using HR-MAS 2D NMR spectroscopy 

Akram BELGHITH1, Christophe COLLET2, Karim ELBAYED3, Lucien RUMBACH4, Izzie Jacques NAMER5, and Jean-Paul ARMSPACH6
1University of Strasbourg, LSIIT - CNRS UMR 7005, Strasbourg, Alsace, France, 2University of Strasbourg, LSIIT - CNRS UMR 7005, France, 3University of Strasbourg, Institut de Chimie, 4Neurology Department CHU Minjoz Besancon -France, 5University of Strasbourg, LINC - CNRS FRE 3289 - France, 6University of Strasbourg, LINC - CNRS FRE 3289, France

In this paper, we propose a new scheme to detect and align simultaneously peaks for biomarker identification. The proposed peak detection and alignment approach is based on the use of evidence theory which is well suited to model uncertainty and imprecision that characterize the 2D NMR HRMAS spectra. The peak detection and alignment results will be then used to identify biomarkers present in the biopsy. We particularly show that the use of fuzzy set theory in our biomarker identification scheme achieves consistently high performance compared to the threshold methods.

Electronic Posters : Other
Click on to view the abstract pdf and click on to view the video presentation.

Monday May 9th
Exhibition Hall  14:00 - 16:00 Computer 42

14:00 3448.   Volumetric Chemical Shift Imaging With Low Power Adiabatic Pulses And Fast Spiral Readouts 

Ovidiu Cristian Andronesi1, Borjan A. Gagoski2, Elfar Adalsteinsson2, and Gregory A. Sorensen1
1Martinos Center for Biomedical Imaging, Radiology Department, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA, United States, 2Electrical Engineering and Computer Science, Massachusetts Institute of Technology, Cambridge, MA, United States

Volumetric MR spectroscopic imaging (MRSI) with improved localization and rapid acquisition was developed for 3T clinical applications. Gradient modulated constant adiabaticity pulses with lower power requirements and shorter durations than typical hyperbolic secant pulses minimize artifacts such as chemical shift displacement error, non-uniform excitation, and lipid contamination. Spiral readout trajectories simultaneously acquire the frequency dimension and two of the spatial dimensions in order to speed up data collection. Four times shorter scan times or 60% smaller voxels in half time compared to conventional phase encoded were acquired on brain tumor patients, with a correspondingly lower but still clinically adequate SNR.

14:30 3449.   Towards Standardization of Volumetric MRSI 

Andrew A. Maudsley1, Sulaiman Sheriff1, Mohammed Sabati1, Meng Gu2, Juan Wei3, Dan Spielman2, Peter Barker3, and Rajesh Garugu1
1Radiology, University of Miami, Miami, FL, United States, 2Radiology, Stanford University, Stanford, CA, United States, 3Radiology, Johns Hopkins University, Baltimore, MD, United States

Implementations of MR spectroscopic imaging vary across sites and instrument manufactures, and are restrictive in terms of the spatial extent over which data is obtained and relative complexity of the data analysis. To address these limitations a volumetric 1H MRSI acquisition has been implemented on instruments from three instrument manufacturers and combined with automated processing procedures. Results indicate comparable performance across all 3 systems and feasibility for multi-site volumetric MRSI studies, with the potential for pooling normative data for reducing costs and increasing sensitivity for clinical studies.

15:00 3450.   Novel Automated 3D MRSI Acquisition with Whole Brain Slice Selection and Outer-Volume Suppression 

Eugene Ozhinsky1,2, Adam B. Kerr3, and Sarah J. Nelson1,4
1Surbeck Laboratory of Advanced Imaging, Department of Radiology and Biomedical Imaging, University of California, San Francisco, San Francisco, CA, United States,2UCSF/UCB Joint Graduate Group in Bioengineering, University of California, San Francisco, 3Department of Electrical Engineering, Stanford University, CA, United States,4Department of Bioengineering and Therapeutic Sciences, University of California, San Francisco

A protocol with automated prescription has been developed for 3D spectroscopic imaging of the brain. Automatic placement of an oblique excitation slice and outer-volume suppression (OVS) bands instead of PRESS localization allowed for a fast prescription including full brain coverage. The use of novel dualband very-selective suppression (VSS) pulses shortened the length of the saturation pulse train and helped achieve sharper transition bands, compared to the existing nonlinear-phase single-band VSS pulses.

15:30 3451.   Multi-slice MRSI at 7T with Dualband Suppression and Hahn Echo Acquisition 

He Zhu1,2, Ronald Ouwerkerk3, Richard Edden1,2, and Peter B. Barker1,2
1Radiology, Johns Hopkins University, Baltimore, Maryland, United States, 2F.M. Kirby Research Center, Kennedy Krieger Institute, Baltimore, Maryland, United States,3NIDDK, National Institute of Health, Bethesda, Maryland, United States

Multi-slice Magnetic Resonance Spectroscopic Imaging (MRSI) was recently combined with a dualband water and lipid suppression sequence with integrated Outer Volume Suppression (OVS) at 3T. In this abstract, a 7T multi-slice MRSI sequence with dualband suppression and Hahn echo acquisition with high bandwidth slice selective pulses and short echo time is presented.

Tuesday May 10th
  13:30 - 15:30 Computer 42

13:30 3452.   Improved spatial localization in 3D MRSI with a sequence combining PSF-Choice, EPSI and a resolution-enhancement algorithm 

Lawrence Patrick Panych1, Bruno Madore1, William S Hoge1, and Robert V Mulkern2
1Radiology, Brigham and Womens Hospital, Boston, MA, United States, 2Radiology, Children's Hospital, Boston, MA, United States

MRSI with PSF-Choice encoding in two directions and with EPSI along the third direction was implemented. PSF-Choice, using a RF manipulation scheme, alters the PSF to obtain a Gaussian shape, eliminating truncation artifact without loss in spatial resolution. With the addition of EPSI, acquisition is accelerated and, during multiple acquisitions to maintain SNR, image data is acquired in such a way that a resolution-enhancement algorithm can be applied. This is possible because of the higher spatial frequency content in the Gaussian-shaped PSF. Results in phantoms on a 3T MRI system were obtained.

14:00 3453.   Phase-Cycled Segmented Center-out Echo Planar Spectroscopic Imaging Sequence 

Christian Labadie1,2, Stefan Hetzer3, Toralf Mildner1, Monique Aubert-Frécon2, and Harald E. Möller1
1Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany, 2Laboratoire de Spectrométrie Ionique et Moléculaire, Université Claude Bernard Lyon 1, France, 3Bernstein Center for Computational Neuroscience, Berlin, Germany

Segmented center-out echo planar spectroscopic imaging implements a k-t-space sampling that reduce the convolution of spatial and temporal encoding by privileging the concomitant acquisition of center k-space lines. Because of the considerable acceleration, a water reference scan can be measured in a few seconds along with a template scan for the realignment of forward and reflected ADC. Spectral Nyquist ghosts that may arise from the use of strong flyback rewinders can be effectively handled by implementing a sixteen step EXOR phase cycling and enables the detection of the J-coupled resonance of glutamate in 2.1 min.

14:30 3454.   Optimized semi-LASER 3D MRSI sequence for lactate detection in the prostate 

Thiele Kobus1, Arend Heerschap1, and Tom W.J. Scheenen1
1Radiology, Radboud University Nijmegen Medical Centre, Nijmegen, Gelderland, Netherlands

3D MRSI with adiabatic refocusing pulses was optimized for lactate detection in the prostate. Echo time and inter-pulse delays of the AFP pulses were optimized for an in phase citrate shape and anti-phase lactate signals. Simulations, phantom and in vivo measurements were performed. In 3 patients with advanced prostate cancer lactate signals remained below the minimal detectable lactate levels of around 1 mM.

15:00 3455.   Selective Zero-Quantum Coherence Transfer (Sel-ZQC) Method for High-Resolution Metabolite Imaging at Ultrahigh Field without Inhomogeneous Broadening and Susceptibility Artifacts 

Song Chen1, and Qiuhong He1,2
1Radiology, University of Pittsburgh, Pittsburgh, PA, United States, 2Bioengineering, University of Pittsburgh, Pittsburgh, PA, United States

The Sel-ZQC pulse sequences were developed to detect the high-resolution zero-quantum NMR signals of metabolites without subjecting to inhomogeneous broadening and magnetic susceptibility artifacts at ultrahigh fields. The sequence completely suppresses the lipid and water resonances that block the observation of metabolite signals. The in vivo Sel-ZQC method may be applied to study breast cancer or other human diseases in extracranial organs in the presence of high mobile fat concentration.

Electronic Posters : Other
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Perfusion & Permeability Methodology

Monday May 9th
Exhibition Hall  14:00 - 16:00 Computer 43

14:00 3456.   The influences of albumin binding and field strength on the relaxivity of gadofosveset (Ablavar), and its potential beyond angiography as clinical field strengths increase 

Owen Carl Richardson1, Steven F Tanner1, Marietta Scott2, and David L Buckley1
1Division of Medical Physics, University of Leeds, Leeds, West Yorkshire, United Kingdom, 2AstraZeneca, Alderley Park, Cheshire, United Kingdom

The contrast agent gadofosveset (Ablavar) displays altered relaxivity and kinetic behaviour on binding with albumin. This study investigates gadofosveset relaxivity variance with field strength, and binding site influence on model fitting. Free and observed relaxivities were calculated from measured T1 relaxation times for in vitro gadofosveset solutions with/without albumin at four field strengths and concentrations ¡Ü 10mM. Bound relaxivity was calculated using a model fit for 1-3 binding sites at low and high concentrations. Single binding underestimates high-concentration relaxivity at low fields. Bound and free gadofosveset relaxivities converge at high fields, although the kinetics characteristics remain a differentiating feature.

14:30 3457.   Nano-Osmotic Coupling in Active Cell Membrane Water Permeability 

Yajie Zhang1, Marie Poirier-Quinot1, Charles S Springer, Jr.2, and James A Balschi1
1Physiological NMR Core Laboratory, Brigham and Women's Hospital, Boston, MA, United States, 2Advanced Imaging Research Center, Oregon Health & Science University, Portland, OR, United States

The mean intracellular water lifetime, lower case Greek taui, is a DCE-MRI parametric biomarker proportional to (size)/PW, where (size) and PW are mean linear cell size and cell membrane water permeability coefficient measures, respectively. Cell suspension studies allow precise lower case Greek taui measurement and manipulation of its determinant factors. Here, yeast cells are treated with ebselen, an inhibitor of the cell membrane H+ATPase. Oxygenation of anaerobic yeast decreases lower case Greek taui. This decrease is inhibited by ebselen. This demonstrates that PW has an active component reflecting nano-osmotic coupling. Rapid, equilibrium trans-membrane water cycling is driven in part by homeostatic ion cycling.

15:00 3458.   Cerebral blood volume fraction quantification in mice 

Teodora-Adriana Perles-Barbacaru1, Francois Berger2, and Hana Lahrech1
1INSERM U836, functional and metabolic neuroimaging, Grenoble Institute of Neurosciences, University Joseph Fourier, Grenoble, France, 2INSERM U836, brain nanomedicine group, Grenoble Institute of Neurosciences, University Joseph Fourier, Grenoble, France

Noninvasive quantification of regional cerebral blood volume fraction (BVf) by magnetic resonance (MR) imaging can be used to map brain dysfunction and to monitor drug efficacy in patients and in preclinical studies. This study demonstrates that the Rapid Steady State T1 MR technique, previously used with intravenous contrast agent injections in rats, can be used with intraperitoneal injections of Gd-DOTA to safely and reliably acquire cerebral BVf maps in mice during a comfortable time interval of at least 20 minutes.

15:30 3459.   3D Cartesian Volumetric Liver Perfusion MRI with High Temporal and Isotropic Spatial Resolution 

Kang Wang1, Frank Korosec1, Yin Huang1, Kevin Johnson1, Ethan Brodsky2, Reed Busse3, James Holmes3, Jean Brittain3, and Scott Reeder1,4
1Medical Physics, University of Wisconsin-Madison, Madison, WI, United States, 2Biomedical Engineering, University of Wisconsin-Madison, Madison, WI, United States,3Global Applied Science Laboratory, GE Healthcare, 4Radiology, University of Wisconsin-Madison, Madison, WI, United States

MR liver perfusion is a non-invasive imaging method to assess of the blood supply to liver tumors, providing quantitative measurements of the early changes in liver tumor microvascularity with chemotherapy that may predict long-term tumor response. However, quantitative liver perfusion has been challenging due to the requirement for entire liver coverage, high spatial and high temporal resolution. The purpose of this study is to demonstrate the feasibility of overcoming these technical challenges using a previously developed Interleaved Variable Density sampling method with parallel imaging and Cartesian HYPR reconstruction.

Tuesday May 10th
  13:30 - 15:30 Computer 43

13:30 3460.   Bias and precision for hemodynamic parameters resulting from ‘best model’ and ‘weighted model’ strategies based on the Akaike Information Criterion 

Robert Luypaert1, Steven Pieter Sourbron2, and Johan de Mey1
1UZ Brussel - Radiology, Vrije Universiteit Brussel, Brussels, Brussels, Belgium, 2Medical Physics, University of Leeds, Leeds, United Kingdom

The Akaike Information Criterion, which can rank pharmacokinetic models on the basis of goodness-of-fit and number-of-parameters, was applied to the exchange model (general) and the modified Tofts model (valid for negligible plasma mean transit time). Data with fixed noise level and varying validity of the Tofts model were simulated using the exchange model. Bias and precision for parameter estimates obtained by selecting the model with highest Akaike score (‘best model’) and by calculating weighted averages based on the Akaike scores (‘weighted model’) were studied. Although both approaches led to optimized estimates, unexpected properties that could hamper their usefulness were detected.

14:00 3461.   R1 and R2* changes according to Gd concentration: a potential limiting factor in converting MR signal intensity to Gd concentration 

Jeong Kon Kim1,2, Ravi Teja Seethamraju3, Ji-Yeon Suh1,2, Gyounggoo Cho4, Woo Hyun Shim2,5, and Young Ro Kim2
1Department of Radiology, Research Institute of Radiology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Seoul, Korea, Republic of, 2Radiology, Athinoula A. Martinos Center for Biomedical Imaging, Charlestown, MA, United States, 3SIEMENS Medical Solutions USA, Inc, Boston, MA, United States, 4MRI team, Korea Basic Science Institute, 5Bio & Brain, Korea Advanced Institute of Science and Technology

When 0.1 mol/kg of Gd is injected, plasma concentration of Gd ranges from 2.83 to 12.64 mM according to the time sequence. In our phantom study, R1 reached plateau at approximately 7.5 mM and R2* exponentially increased with increasing Gd concentration. Therefore, R2* effect becomes dominant over R1 effect at high Gd concentration, such as 7.5 mM or greater. These patterns of R1 and R2* changes may limit conventional methods converting MR signal intensity to Gd concentration, particularly in measuring arterial input function, as they consider that delta R1 is linearly proportional to Gd concentration and R2* effect is negligible.

14:30 3462.   A population pharmacokinetic model for Gd-DTPA in small animal DCE-MRI 

Andreas Steingoetter1, Dieter Menne2, and Rickmer Braren3
1Division of Gastroenterology and Hepatology, University Zurich, Zurich, Switzerland, 2Menne Biomed Consulting, Tuebingen, Germany, 3Institute of Radiology, Klinikum rechts der Isar der TU München, Munich, Germany

Integration of several individual tissue concentration curves within a study population could allow for the development of complex multiple compartment models. Based on population nonlinear mixed effects (popPK) modeling using NONMEM® 7, this study aimed at developing and evaluating a robust multi-compartment popPK model for Gd-DTPA in a rat hepatocellular carcinoma (HCC). The final numerically stable model, consisting of 3 observed (muscle, tumor, liver) and 6 unobserved compartments, was validated using standard numerical criteria (i.e. weighted residuals, caterpillar plots, objective function value, standard errors, matrix condition number) and quantitative histological analysis (tumor necrosis).

15:00 3463.   In Vivo Measurement of Blood Transit Time in Rat Brain using the Saturation Recovery-T1app Imaging Method 

Xiao Wang1, Xiao-hong Zhu1, Yi Zhang1, and Wei Chen1
1Center for Magnetic Resonance Research, Department of Radiology, University of Minnesota Medical School, Minneapolis, MN, United States

A two-phase spin model was proposed for quantifying the dynamic magnetization change of the saturation recovery T1app (SR-T1app) measurement, and determining CBF and blood transit time, which is a physiologically and pathologically important parameter and sensitive to the status of hemodynamic impairment in cerebrovascular disorders, for example, in stroke. The estimated transit times in the rat brain using SR-T1app measurement and the two-phase spin model showed excellent consistency and reproducibility under both normocapnia (280±16 ms) and mild hypercapnia (218±10 ms) conditions, and they are in coincidence with literature reports ranged from 100 to 400 ms. Therefore, the new SR-T1app method not only offers a noninvasive and simple tool for mapping rat brain CBF change, but also provides a promising way for estimating brain blood transit delay in vivo.

Electronic Posters : Other
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Wednesday May 11th
Exhibition Hall  13:30 - 15:30 Computer 44


Ana Gonzalez-Segura1, Miguel Cerda-Nicolas2, Concha Lopez-Gines2, Jose Manuel Gonzalez-Darder3, Jose Manuel Morales2, and Daniel Monleon1
1Fundacion Investigacion HCUV, Valencia, Valencia, Spain, 2Universidad de Valencia, 3Hospital Clinico Valencia

The aim of this study was the characterization by Magnetic Resonance Microscopy of specific morphological features of brain tumors. With this purpose, we performed MRM imaging and correlative histopathology in 30 biopsies from brain tumor patients. The correlation between MRM and histopathology images allows the determination of MRI parameters for critical microstructures of the tumor. The MRM analysis of meningioma and glioma biopsies revealed microstructural details of these tumors, which may add some information for clinical MRI images interpretation. We believe that our results have also potential pathobiological significance as MRM is capable of exploring the biopsy before processing it.

14:00 3465.   A Microfluidic Micro-MRI Set-up to Assess the Specificity of Targeted Contrast Agents on a Living Cell Monolayer 

Nicolas Gargam1, Marie Poirier-Quinot1, Jean-Sébastien Raynaud2, Philippe Robert2, and Luc Darrasse1
1IR4M (UMR 8081), Université Paris-Sud - CNRS, Orsay, France, 2Guerbet Research, Paris, France
The development of targeted contrast agents (CA) is of great interest to increase the specificity of MRI. Proof of concept studies are required to establish the detectability of the CA and analyze the role of molecules and cells in the contrast mechanisms. This study proposes a full method to detect a single KB cell layer in a microfluidic channel by micro-MRI at 2.35T to assess the specificity of P866 (Guerbet, France), a CA which targets the folate receptor on cells’ membrane. The proposed set-up can be extended to different molecular targets and other CA such as USPIOs.

14:30 3466.   Biexponential T2 approach to investigate water organization and molecular mobility of hydrated HPMC dosage forms. Influence of drug substances with different water solubility. 

Anna Mlynarczyk1, Krzysztof Jasinski1, Piotr Kulinowski1, Marco L.H. Gruwel2, Przemys³aw Dorozynski3, Boguslaw Tomanek1,2, and Wladyslaw P Weglarz1
1Department of Magnetic Resonance Imaging, Institute of Nuclear Physics PAN, Krakow, Poland, 2Institute for Biodiagnostics, National Research Council of Canada, Winnipeg, Manitoba, Canada, 3Department of Pharmaceutical Technology and Biopharmaceutics, Jagiellonian University, Krakow, Poland

MRI time-resolved approach was used to measure spatial distribution of T2 and PD of HPMC-based tablets during hydration. Biexponential T2 data analysis approach was used to distinguish regions with different water organization and molecular mobility. Influence of two active substances, that are freely (L-dopa) and poorly (Ketoprofen) soluble on matrix structure during hydration was tested. In all cases hydrated area consists of several separated sub-areas (layers) with well-defined properties: dry-glassy-polymer, infiltration-layer, solid-swollen-layer, gel-layer. Subpixel-level heterogeneity during hydration was clearly visible. In case of Ketoprofen formulation, gel layer area is not present which has great influece on drug dissolution during hydration.

15:00 3467.   Cellular level MR Phase Contrast Microscopy and MEMRI of MnCl2 labeled tumor cells with direct optical correlation 

Nicoleta Baxan1, Ulf Kahlert2, Juergen Hennig1, and Dominik von Elverfeldt1
1Dept. of Radiology, Medical Physics, University Medical Center Freiburg, Freiburg, Germany, 2Department of Stereotactic Neurosurgery, University Medical Center Freiburg, Freiburg, Germany

In this study, we present for the first time the ability of the microcoil-based phase contrast MRI to resolve cellular structure of human glioma neurospheres, at significantly improved resolutions (10 ×10 µm2) with direct optical image correlation. Furthermore, after cell labeling with manganese chloride (MnCl2), the paramagnetic properties of manganese were exploited using phase imaging to further enhance the contrast of cell structure. The MnCl2 property to function as a T1 contrast agent, enabled to follow temporal changes of MnCl2 uptake, retention and release time within and from single cells and individual clusters.

Electronic Posters : Other
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MRS of Cells, Body Fluids & Others
Thursday May 12th
Exhibition Hall  13:30 - 15:30 Computer 45

13:30 3468.   Metabolic Regulatory Variation in rat Serum due to Cold Stress: High Resolution 1H NMR approach 

Sonia Gandhi1, Hemanth Kumar Bhonsle Somu1, Memita Devi1, Sunil Pal2, Rajendra P Tripathi1, and Subash Khushu1
1NMR Research Centre, Institute of Nuclear Medicine & Allied Sciences, DRDO, Delhi, Delhi, India, 2Division and Cyclotron & Radiopharmaceutical Sciences, Institute of Nuclear Medicine & Allied Sciences, DRDO, Delhi, Delhi, India

Prolonged/repeated cold stress is recognized as a risk factor for many disorders including cardiovascular diseases, myocardial infarction, depression, increased sympathetic activity causing neuro-humoral and metabolic changes for adaptation. Present study investigates the changes in metabolic profiles of serum in rats due to prolonged cold stress using NMR & multivariate statistical analysis (PCA). Results shows marked increase in metabolites viz lactate, alanine and glucose on prolonged cold exposure for 15 days indicating changes in carbohydrate and energy metabolism. Noninvasive monitoring of various biochemical pathways can be done & these results can be used to develop strategies to sustain cold stress.

14:00 3469.   Metabolic profiling of human liver fibrosis 

Jose Manuel Morales1, Beatriz Martinez-Granados2, Juan del Olmo3, Bernardo Celda2, Jose Manuel Rodrigo1,3, and Daniel Monleon4
1Universidad de Valencia, Valencia, Valencia, Spain, 2Universidad de Valencia, 3Hospital Clinico Valencia, 4Fundacion Investigacion HCUV, Valencia, Valencia, Spain

Liver fibrosis is characterized by the replacement of liver tissue by fibrous scar tissue as well as regenerative nodules, leading to progressive loss of liver function and to altered liver metabolism. Cirrhosis is the end-stage of this reaction and it represents a major change in the tissue. Global metabolic profiles, which are affected by many physiological and pathological processes, may reflect accurately the presence of a particular disease state. The aim of this study is to demonstrate the applicability of 1H HR-MAS NMR spectroscopy biochemical profile determination in human liver needle biopsy as support for the assessment of chronic liver disease stage. Metabolic profiles of chronic liver disease biopsies provided differential patterns between cirrhosis and non cirrhosis and allow the determination of progressive metabolic alterations associated to chronic hepatic disease. In this work, we report that metabolic alterations associated to liver disease stage affect essential metabolic processes beyond lipid metabolism. Early stages of chronic liver disease seem to have important metabolic consequences including increased glutamate and decreased glutamine and glucose. Overall, this work suggests that the additional information obtained by NMR metabolomics applied to needle biopsies of human liver may be useful for assessing metabolic alterations and liver dysfunction in chronic liver disease.

14:30 3470.   High resolution 1H NMR spectroscopy successfully discriminates fetuses with congenital diaphragmatic hernia from normal pregnancies 

Anca Ramona Croitor Sava1, Veronika Beck2,3, Inga Sandaite4, Jan Deprest2,3, Filip Claus4, Sabine Van Huffel1, and Uwe Himmelreich5
1Depart. Electrical Eng. – ESAT/SCD, Katholieke Universiteit Leuven, Leuven, Belgium, 2Division Woman and Child, University Hospital Gasthuisberg, Leuven, Belgium,3Centre for Surgical Technologies, Katholieke Universiteit Leuven, Leuven, Belgium, 4Division of Medical Imaging, University Hospital Gasthuisberg, Leuven, Belgium, 5Dept. Medical Diagnostic Sciences – Biomedical NMR Unit, Katholieke Universiteit Leuven, Leuven, Belgium

High resolution 1H NMR spectroscopy is performed to compare amniotic fluid from fetuses with congenital diaphragmatic hernia undergoing temporary tracheal occlusion or its reversal against healthy controls. Principle Component Analyses and Multidimensional Scaling are separately applied in combination with various automated classification techniques for differentiating the complicated pregnancies. Results show that dimensionality reduction methods in combination with automated classifiers when analyzing 1H NMR spectra have a high potential in identifying complicated pregnancies. Thus, it can represent an attractive tool which combined with routine fetal magnetic resonance imaging could help to obtain a more detailed picture of the fetal status.

15:00 3471.   Hypoxia Increases Degradation of the Extracellular Matrix by Human Breast Cancer Cells 

Tariq Shah1, Balaji Krishnamachary1, Flonne Wildes1, Yelena Mironchik1, and Zaver M Bhujwalla1
1Radiology, Johns Hopkins University, Baltimore, Maryland, United States

Hypoxia is frequently observed in tumor microenvironments and plays a significant role in the aggressive phenotype. The ability to degrade and invade into extracellular matrix (ECM) is a critical requirement in the metastatic cascade. The ability to metastasize is one of the most lethal aspects of cancer. Here, using our MR-compatible cell perfusion assay, we have investigated the effect of hypoxia on the ability of MDA-MB-231 breast cancer cells to degrade ECM. Hypoxia induced a significant increase of ECM degradation, and altered metabolism. These data suggest that hypoxia may be a potent facilitator of ECM degradation in tumors.