Quantitative Susceptibility Mapping (QSM)

Tuesday 2 June 2015

Yi Wang¹, Dong Zhou¹, and Pascal Spincemaille^1
1Cornell University, New York, New York, United States

The imaginary Lorentz sphere is used to calculate the tissue susceptibility induced field observed by water protons in MRI, which has led to unsettling discussions. Using spatial smoothing of microscopic quantities to derive macroscopic quantities, tissue is modeled as a continuous medium with steady electronic susceptibility sources and steady proton observers. The magnetic field is described as distribution. The electronic sources and proton observers have to be spatially separated to preserve the definition of susceptibility. This leads to the Cauchy principal value integration of the dipole kernel over tissue magnetization for calculating the susceptibility field, without referring the observer geometry.

Tianyou Xu¹, Sean Foxley¹, and Karla Miller^1
1Oxford Centre for Functional Magnetic Resonance Imaging of the Brain, University of Oxford, Oxford, Oxfordshire, United Kingdom

Previous works aimed at describing the relation between susceptibility-driven properties of white matter and the resultant MR signal have relied on models consisting of only hollow cylinders, which simulate axons and their myelin sheaths. While these models benefit from simplicity, they do not capture the full diversity of microstructures present in white matter. Other neuroglia, with their distinct magnetic susceptibilities and volumes, may also have significant influence modulating the MR signal. We demonstrate that the incorporation of iron-rich oligodendrocytes has a significant impact on the underlying frequency distribution and MR signal by virtue of their nontrivial volume fractions and magnetic susceptibility.

Alexander Ruh¹ and Valerij G. Kiselev^1
1Dept. of Radiology, Medical Physics, University Medical Center Freiburg, Freiburg, Germany

The notion of the Lorentz cavity is fundamental for NMR. It has been recently revised to include effects of fine magnetic structure carried by the cellular architecture in biological tissues such as brain white matter. We point out that the inclusion of cells in the Larmor cavity crucially depends on the relation of their size to the diffusion length during the acquisition of the free induction decay (FID). We demonstrate using numerical simulations how the cavity field interpolates between the classical value for small cells and the generalized one for large cells.

Jeam Haroldo Oliveira Barbosa^1,2, Rafael Emídio³, Ana Tereza Di Lorenzo Alho³, Camila Fernandes Nascimento³, André Henrique Fais Silva¹, Alexandre Valotta Silva³, Maria Conception Garcia Otaduy³, Maria da Graça Martin³, Edson Amaro Junior³, Oswaldo Baffa¹, and Carlos Ernesto Garrido Salmon^1,4
1Department of Physics - FFCLRP, University of Sao Paulo, Ribeirao Preto, Select, Brazil, ²CNRS, ICube, FMTS, Université de Strasbourg, Strasbourg, Bas-Rhin, France,³Department of Radiology - FM, University of Sao Paulo, Sao Paulo, Sao Paulo, Brazil, ⁴University of Nottingham, Sir Peter Mansfield Magnetic Resonance Center, Nottingham, Bas-Rhin, United Kingdom

Correlation between paramagnetic ions and quantitative susceptibility values of postmortem brain study: QSM showed sensitive and specific only for the paramagnetic ion Fe+3 present in no-haem proteins as transferrin and ferritin.

Shunshan Li¹, Mark J Fisher², Ronald C Kim³, David Cribbs⁴, Mark J Hamamura¹, Vitaly Vasilevko⁴, Annlia P Hill², and Min-Ying Su^1
1Tu&Yuen Center for Functional Onco-Imaging, University of California, Irvine, CA, United States, ²Department of Neurology, University of California, Irvine, CA, United States,³Department of Pathology, University of California, Irvine, CA, United States, ⁴Institute for Memory Impairments and Neurological Disorders, University of California, Irvine, CA, United States

It is difficult to confirm microbleeds found in in-vivo MRI with pathological examination. Specimen imaging may be used to verify the detected microbleeds and further to correlate with disease progression of patients before death. In this study 27 brains were imaged. A special vacuum chamber with ultrasound probe was built to remove bubbles on the surface of the specimen. Microbleeds were found in 16/27=59% cases. Of 16 cases with confirmed pathology, microbleeds were found in 3/9=33% normal aging subjects, and in 3/5=60% Alzheimer’s disease patients. An analysis software is being developed to improve the detection sensitivity and size quantification.

Alexey Dimov^1,2, Thanh Nguyen², Zhe Liu^1,2, Kofi Deh², Jingwei Zhang^1,2, Martin Prince², and Yi Wang^1,2
1Biomedical Engineering, Cornell University, Ithaca, NY, United States, ²Radiology, Weill Cornell Medical College, New York, NY, United States

Oxygen level is a quantity of interest for studying ischemia, arteriovenous shunts, and the assessment of muscle metabolic properties. In this study, we present in vivo results of estimating venous blood oxygenation using quantitative susceptibility mapping. Comparison with blood oximetry showed high degree of correlation.

Ching-Yi Hsieh¹, Yu-Chung Norman Cheng¹, Jaladhar Neelavalli¹, and E. Mark Haacke^1
1Wayne State University, Detroit, MI, United States

We showed the alternative approach to quantifying magnetic moment, susceptibility and cross-sectional area of veins in human without any a priori information. By summing up MR signals surrounding the object, the magnetic moment, susceptibility and the cross-sectional area of the object can be solved. Here, we tackled three practical issues-low signal to noise ratio inside the object, local background field and the cylindrical object at the low orientation to the main field. The results of the susceptibility in veins agree with the recent published papers.

Henry H. Ong¹, Robert A. Horch^1,2, John C. Gore¹, and E. Brian Welch^1
1Vanderbilt University Institute of Imaging Science, Nashville, TN, United States, ²Radiology and Radiological Sciences, Vanderbilt University, Nashville, TN, United States

Characterization of the magnetic susceptibility () of biological tissues may provide insight into their composition and microarchitecture. Despite their biological significance for energy storage and metabolic regulation, there have been few reports of the magnetic properties of white adipose tissue (WAT) and, to the best of our knowledge, none on brown adipose tissue (BAT). For the first time, we report ex vivo MRI susceptometry measurements of murine BAT and WAT. WAT  agreed with previous reported values, while BAT was measured to be even more diamagnetic than water. Further study is needed to elucidate the basis of this difference.

Samir D. Sharma¹, Bjoern P. Schoennagel², Jin Yamamura², Peter Nielsen², Regine Grosse², Hendrik Kooijman³, Roland Fischer^2,4, Diego Hernando¹, Gerhard Adam², Peter Bannas¹, and Scott R. Reeder^1,5
1Radiology, University of Wisconsin, Madison, WI, United States, ²University Medical Center Hamburg-Eppendorf, Hamburg, Germany, ³Philips Healthcare, Hamburg, Germany,⁴UCSF Benioff Children's Hospital Oakland, Oakland, CA, United States, ⁵Medical Physics, University of Wisconsin, Madison, WI, United States

Assessment of iron burden is essential for the longitudinal monitoring and treatment of patients with liver iron overload. The purpose of this work was to investigate the relationship between MR-based R2* and quantitative susceptibility mapping (QSM) with SQUID-based biomagnetic liver susceptometry in patients with suspected liver iron overload. Eleven patients were recruited for this study from a population undergoing cardiac MRI and liver susceptometry as part of their regular iron monitoring. The correlation between R2* and SQUID was found as R² = 0.88. Linear regression analysis between QSM and SQUID yielded: slope = 0.63±0.09, y-intercept = -0.38±0.23, R² = 0.87. 

Jingwei Zhang^1,2, Cynthia Wisnieff^1,2, Becky Schur³, Lu Zhengrong³, David Pitt⁴, and Yi Wang^1,2
1Biomedical Engineering, Cornell University, New York, New York, United States, ²Radiology, Weill Cornell Medical College, New York, New York, United States, ³Biomolecular Engineering, Case Western Reserve University, Ohio, United States, ⁴Neurology, Yale School of Medicine, CT, United States

This study aims at demonstrating the feasibility of correcting calcium susceptibility for more accurate [Fe] maps utilizing both QSM and CT images in brain specimens. The results are compared with ICP-OES results served as the golden standard.

Rüdiger Stirnberg¹, Julio Acosta-Cabronero², Benedikt A. Poser³, and Tony Stöcker^1,4
1German Center for Neurodegenerative Diseases (DZNE), Bonn, Germany, ²German Center for Neurodegenerative Diseases (DZNE), Magdeburg, Germany, ³Faculty of Psychology and Neuroscience, Maastricht University, Maastricht, Netherlands, ⁴Department of Physics and Astronomy, University of Bonn, Bonn, Germany

Recently, the feasibility of quantitative susceptibility mapping (QSM) at 3 Tesla using segmented 3D-EPI requiring only a fraction of conventional gradient echo (GRE) acquisition times, has been demonstrated. Moving to higher field strengths usually involves higher spatial resolutions and shorter echo times. The use of additional in-plane segmentation in 3D-EPI is proposed here to meet both requirements at 7 Tesla. Multiple R₂* weightings further increase the sequence flexibility. QSM results at 0.8mm in-plane resolution show that more than one EPI average is hardly needed when compared to GRE. More advanced applications, such as susceptibility tensor imaging, thus become feasible.

Christian Langkammer¹, Berkin Bilgic¹, Celine Louapre¹, Costanza Gianni¹, Sindhuja T Govindarajan¹, Kawin Setsompop¹, and Caterina Mainero^1
1MGH/HST Martinos Center for Biomedical Imaging, Harvard Medical School, Boston, MA, United States

In this work we combined a novel efficient acquisition approach based on 3D gradient recalled echo with wave-CAIPI acceleration for its usefulness in quantitative susceptibility mapping at higher spatial resolution. The proposed setup allows QSM of the entire brain with 0.5 mm isotropic resolution in 4 minutes.

Paul Polak¹, Robert Zivadinov^1,2, and Ferdinand Schweser^1,2
1Department of Neurology, Buffalo Neuroimaging Analysis Center, State University of New York at Buffalo, Buffalo, NY, United States, ²Molecular and Translational Imaging Center, MRI Center, Clincal and Translational Research Center, Buffalo, NY, United States

Gradient echo (GRE) imaging has received increased attention because of the GRE signal's effectiveness in elucidating information about magnetic tissue properties and microscopic tissue architecture. However, multi-echo GRE sequences are hindered by their lengthy acquisition times. Multi-shot GRE 3D echo-planar imaging (EPI) attempts to circumvent this problem by acquiring multiple k-space lines per shot – but what effect these acquisition strategies have on the underlying magnitude and phase components is not clear. In this work we systematically investigate the effect of magnitude signal decay and phase evolution during the readout on the accuracy of complex-valued GRE signals measured with simulated segmented 3D EPI sequences.

Xiang Feng¹, Alexander Loktyushin², Andreas Deistung¹, and Juergen R. Reichenbach^1
1Medical Physics Group, Institute of Diagnostic and Interventional Radiology, Jena University Hospital - Friedrich Schiller University Jena, Jena, Germany, ²Empirical Inference, Max Planck Institute for Intelligent Systems, Tübingen, Germany

Subject motion during MR scans can cause motion artifacts in magnitude and phase images, and impair subsequent quantitative susceptibility mapping and R2* analysis. We propose using an autofocusing-based fully data-driven retrospective rigid motion correction approach (GradMC) to suppress the motion artifacts in both magnitude and phase images prior to computing QSM and R2*. Our experiments demonstrate the improved accuracy of QSM and R2* techniques in the presence of subject motion, and open promising directions for the future research.

Maximilian Maerz¹, Dong Zhou², Yan Zhang^2,3, Pascal Spincemaille², Lars Ruthotto¹, and Yi Wang^2
1Department of Mathematics and Computer Science, Emory University, Atlanta, GA, United States, ²Weill Cornell Medical College, New York, NY, United States, ³Department of Radiology, Tongji Hospital, Huazhong University of Science and Technology, Wuhan, Hubei, United States

Gradient is an essential operation in the reconstruction of quantitative susceptibility mapping (QSM). There are central difference and short difference implementation for gradient. We found that different finite difference methods strongly affect image quality in data sets acquired with low resolution (greater than 1mm). Checker board pattern artifacts appeared in the central difference implementation and were effectively suppressed with the short difference implementation.

Samir D. Sharma¹, Diego Hernando¹, Debra E. Horng^1,2, and Scott B. Reeder^1,2
1Radiology, University of Wisconsin, Madison, WI, United States, ²Medical Physics, University of Wisconsin, Madison, WI, United States

Quantitative susceptibility mapping (QSM) in the liver has focused on the reconstruction of the susceptibility map from the B₀ field, whereas little consideration has been given to the data acquisition. The purpose of this work was to optimize the data acquisition parameters for QSM in the liver. We calculated the Cramér-Rao Bound (CRB) on the B₀ field and performed Monte-Carlo simulations to optimize the data acquisition. CRB analysis and Monte-Carlo simulations revealed that generally a shorter first echo time, short echo spacing (~0.5ms), and larger number of echoes result in lower variance of the B₀ field and susceptibility map estimates.

Yajun Ma¹, Wentao Liu¹, Weinan Tang¹, and Jia-Hong Gao^1
1Center for MRI, Peking University, Beijing, Beijing, China

We propose a novel echo shift method, which can simultaneously reduce the scanning time and maintain the high image SNR for T2* weighted imaging.

Ahmed M. Elkady¹, Hongfu Sun¹, and Alan H. Wilman^1
1Dept. of Biomedical Engineering, University of Alberta, Edmonton, AB, Canada

Field of View (FOV) restriction to deep Gray Matter (GM) only would significantly accelerate Quantitative Susceptibility Mapping (QSM) acquisitions, facilitating its clinical use in diseases such as Multiple Sclerosis. However, nonlocal effects of dipole fields require careful examination of accelerated QSM through FOV restriction, which were studied through simulations and in vivo MRI acquisitions in each direction (x,y,z). FOV restriction parallel to the main field (z-axis) was found to significantly reduce QSM accuracy. Optimally, coronal FOV restriction (y-axis) should be used for accelerated QSM, requiring a FOV of 133mm or more to obtain accurate QSM results of deep GM.

Samantha J Holdsworth¹, Thomas Christen¹, Kristen Yeom¹, Jae Mo Park¹, Greg Zaharchuk¹, and Michael E Moseley^1
1Department of Radiology, Stanford University, Stanford, CA, United States

In the present study, we generate multiple contrast mechanisms following the injection of Ferumoxytol (an FDA-approved ultra-small paramagnetic iron oxide [USPIO] compound) in the pediatric brain. The high magnetic susceptibility of ferumoxytol and its long half–life allows the acquisition of high quality/high spatial resolution 3D ME-GRE images in only 5:44-minutes and subsequent generation of R2* maps, field maps, Susceptibility-Weighted Imaging (SWI), Time-of-Flight (TOF), and Quantitative Susceptibility Maps (QSM).

Julio Acosta-Cabronero¹, Arturo Cardenas-Blanco¹, and Peter J Nestor^1
1German Center for Neurodegenerative Diseases (DZNE), Magdeburg, Saxony-Anhalt, Germany

This study explores, with relatively unbiased methods, the relationship between increased paramagnetism in brain parenchyma and age. Brain magnetostatics was probed with quantitative susceptibility mapping (QSM) revealing strong striatal effects as a function of age. In addition, QSM clusters in the diencephalon, mesencephalon—and in a more patchy distribution—, across the cerebral cortex and posterior white matter—also emerged as age-related effects.

Julio Acosta-Cabronero¹, Matthew TJ Betts¹, Arturo Cardenas-Blanco¹, Shan Yang², Oliver Speck², and Peter J Nestor^1
1German Center for Neurodegenerative Diseases (DZNE), Magdeburg, Saxony-Anhalt, Germany, ²Biomedical Magnetic Resonance (BMMR), Otto-von-Guericke University, Magdeburg, Saxony-Anhalt, Germany

This abstract presents a processing pipeline for whole-brain analysis of quantitative susceptibility MRI data. The routine detailed in the abstract consists of an optimised series of QSM and co-registration methods, which yielded highly spatially concordant maps using multi-echo GRE data at 7 Tesla. The present demonstration suggests QSM is ready for large-scale clinical studies.

Benjamín Garzón¹, Grégoria Kalpouzos¹, and Rouslan Sitnikov^2
1Aging Research Center, Karolinska Institute and Stockholm University, Stockholm, Sweden, ²MRI Research Centre, Karolinska University Hospital, Stockholm, Sweden

We present a fully automated algorithm for segmentation of the red nucleus, substantia nigra and subthalamic nucleus from a pair of T1w and quantitative susceptibility (QSM) images, aimed at providing accurate, objective and reproducible segmentations. The algorithm produces spatial probabilistic maps via a multi-atlas label fusion scheme by combining global (T1w) and local (QSM) non-linear registrations. These probabilistic maps are employed as priors in a model representing QSM intensities as a Gaussian mixture. Manual segmentations were obtained for 16 subjects and used to train and validate the model. Cross-validated Dice scores ranged between 0.66 (subthalamic nucleus) and 0.85 (red nucleus).

Joon Yul Choi¹, Yoonho Nam¹, Jingu Lee¹, and Jongho Lee^1
1Department of Electrical and Computer Engineering, Seoul National University, Seoul, Seoul, Korea

In this works, we explored the intra-scan reproducibility of QSM and R2* of the human brain in detail.

Sean Foxley¹, Miriam Domowicz², Nancy Schwartz², and Gregory S Karczmar^3
1FMRIB Centre, University of Oxford, Oxford, OXON, United Kingdom, ²Department of Pediatrics, University of Chicago, Illinois, United States, ³Department of Radiology, University of Chicago, Illinois, United States

Post-mortem mouse brain was imaged using high spectral and spatial resolution MRI. This differs from more conventional susceptibility weighted imaging approached because a water spectrum is produced for each image voxel. Specifically, the FID was sampled in 50x50x70 micron resolution voxels and Fourier transformed to produce water spectra with 3.5 Hz spectral resolution. Waterline asymmetries specific to deep white matter tracts as well as between differing layers of the cerebellum were observed. This indicates that differing microstructurally driven susceptibilities are producing varying resonances in a single voxel, which are detectable using this approach.

Paul Kokeny¹, Xie He², Saifeng Liu³, Ching-Yi Hsieh⁴, Quan Jiang^5,6, Yu-Chung Norman Cheng¹, and E. Mark Haacke^1,4
1School of Biomedical Engineering, Wayne State University, Detroit, MI, United States, ²School of Physics, Wayne State University, Detroit, MI, United States, ³School of Biomedical Engineering, McMaster Univeristy, Hamilton, Ontario, Canada, ⁴Department of Radiology, Wayne State University, Detroit, MI, United States, ⁵Department of Neurology, Henry Ford Health System, Detroit, MI, United States, ⁶Department of Radiology, Henry Ford Health System, Detroit, MI, United States

Currently, the tracking of nanoparticle labeled cells via MRI is a qualitative process. However, given the magnetic moment of a labeled cell cluster along with the mass magnetization of the labeling agent and the average cellular iron uptake, it is possible to estimate the number of cells present in a cluster in vivo. In this work, the magnetic moments of six labeled cell clusters are quantified using a complex summation method that is accurate for small objects. The effect of high-pass filtering is analyzed through simulations. From these results, the number of cells present in each cluster is estimated.

Dirk Krüger¹, Silvia Lorrio González¹, and René M. Botnar^1
1Division of Imaging Sciences & Biomedical Engineering, King's College London, London, United Kingdom

The aim of this project is to develop and validate a Dixon MR imaging technique to achieve positive contrast of very small superparamagnetic iron oxide nanoparticles (VSOPs). We assessed the proposed method in a phantom study and compared the results with three established positive contrast imaging techniques. The reference techniques were GRadient-echo Acquisition for Superparamagnetic particles (GRASP), Inversion Recovery with ON-resonant water suppression (IRON), and Susceptibility Gradient Mapping (SGM). The Dixon method demonstrated superior sensitivity, relative ease of implementation and reliability.

He Xie¹, Yu-Chung Norman Cheng², Ching-Yi Hsieh², Paul Kokeny³, and E.Mark Haacke^2
1Physics and Astronomy, Wayne State University, Detroit, Michigan, United States, ²Radiology, Wayne State University, Detroit, Michigan, United States, ³Biomedical Engineering, Wayne State University, Detroit, Michigan, United States

This study focused on phase measurement in susceptibility quantification. Phase shift due to hyperfine structure was observed in ferritin and iron oxide nanoparticles. Susceptibility quantification results from phase measurement were compared with results from our CISSCO method. The results indicates that a more careful work might be needed before QSM methods can be applied to the phase images. This study also suggests that CISSCO is a reliable quantification method for magnetic susceptibility.

Qun He¹, Zhe Liu², Tian Liu², Yi Wang², and Jiang Du^1
1Radiology, UC, San Diego, San Diego, CA, United States, ²Biomedical Engineering, Cornell University, Ithaca, New York, United States

A combination of 3D UTE and QSM (UTE-QSM) approach was used to access the susceptibility map using of a cortical bone sample using a clinical 3T scanner.

Dongmei Wu¹, Sagar Buch², Saifeng Liu², and E. Mark Haacke^1,3
1Shanghai Key Laboratory of Magnetic Resonance, East China Normal University, Shanghai, China, ²School for Biomedical Engineering, McMaster University, Hamilton, Ontario, Canada, ³Department of Radiology, Wayne State University School of Medicine, Detroit, MI, United States

In this abstract, we present a fully flow compensated double echo sequence with alternating readout gradients for the reconstruction of both MR angiography and MR venography simultaneously. We then use the phase from both the positive and negative polarities to extract the non-compensated flow phase arising from background field inhomogeneities and acceleration effects. This phase is then removed from the original phase to provide a more pristine phase image from which we can create better SWI and QSM images. This new approach makes it possible to do SWI and QSM in practical clinical settings.

Hongpyo Lee¹, Yoonho Nam², Dongyeob Han¹, Sung-Min Gho¹, and Dong-Hyun Kim^1
1Electrical & Electronic Engineering, Yonsei University, Seodaemun-gu, Soeul, Korea, ²Electrical & Computer Engineering, Soeul National University, Gwanak-gu, Soeul, Korea

Susceptibility Imaging can be useful for assessing structural integrity in the spinal cord, which plays an important role in many neurological disorders.1 However, physiological noise from respiration causes artifacts in in-vivo images. This phenomenon is particularly evident in the Cervical-spinal (C-spine) cord because the distance between the C-spine and the lungs is closer than other regions 2. In order to characterize and correct these respiration-induced artifacts of images, navigator echo approaches have been widely used in functional MRI, Diffusion Imaging etc 3 In this study, B0 shift due to respiration is analyzed and this effect is compensated using navigator echoes. Susceptibility weighted image (SWI) of the C-spine is obtained using the correction scheme.

Zahra Hosseini¹, Junmin Liu², and Maria Drangova^2,3
1Biomedical Engineering Graduate Program, Western University, London, Ontario, Canada, ²Imaging Research Laboratories, Robarts Research Institute, London, Ontario, Canada,³Medical Biophysics, Western University, London, Ontario, Canada

Susceptibility weighted imaging (SWI) allows for visualization of veins using intrinsic tissue properties. This technique has gained popularity in the clinic in the past decade. SWI requires accurate phase images in order to generate a reliable mask and ultimately good contrast between veins and adjacent structures. Multi-channel acquisition therefore requires a channel combination technique that preserves the quality of the phase image. We present the application of the inter-echo variance channel combination technique for SW imaging and demonstrate single-slice SWI for the first time.

Curtis A. Corum¹, Lauri J. Lehto², Djaudat S. Idiyatullin¹, Olli Gröhn², and Michael Garwood^1
1Center for Magnetic Resonance Research, Radiology, University of Minnesota, Minneapolis, Minnesota, United States, ²Department of Neurobiology, Biomedical Imaging Unit, A. I. Virtanen Institute for Molecular Sciences, University of Eastern Finland, Kuopio, Northern Savonia, Finland

Susceptibility weighted imaging and quantitative susceptibility mapping are sensitive to magnetic field changes due to tissues and exogenous agents. For many tissues, pathologies, and contrast agents of interest (such as magnetic nanoparticles), quantification is desirable and full mapping of the susceptibility or other electrical properties is not yet practical. An intermediate approach may be useful. We combine a dipole matched filter to count dipole sources in the field of view with model based dipole source decomposition of the phase offsets in 3D radial sampled data.

Zhaolin Chen¹, Guillaume Gilbert², and Miha Fuderer^1
1Clinical Excellence and Research, R&D, Philips Healthcare, Best, Noord-Brabant, Netherlands, ²MR Clinical Science, Philips Healthcare, Montreal, Canada

In this work, a non-linear echo combination approach is introduced to optimize susceptibility contrast in multi-echo SWI. A voxel-wise non-linear combination of magnitude images is introduced prior to calculating SW images. The analytical SNR and CNR of the proposed echo-combination approach are derived and are used to compare the proposed multi-echo approach with the existing single-echo and multi-echo approaches. As shown both experimentally and analytically, the proposed approach provides enhanced susceptibility contrast compared with previous single-echo and multi-echo approaches.

Amanda Ching Lih Ng¹, Shawna Farquharson², Sonal Josan³, and Roger J Ordidge^1
1Dept of Anatomy and Neuroscience, The University of Melbourne, The University of Melbourne, VIC, Australia, ²Imaging, The Florey Institute of Neuroscience and Mental Health, Melbourne, VIC, Australia, ³Siemens Healthcare, Melbourne, VIC, Australia

SWI processing traditionally involves homodyne filtering of the raw complex image data to simultaneously unwrap and high pass filter the phase. In regions where there are high phase gradients, homodyne filtering may inadequately unwrap and filter the phase, resulting in substantial artefacts that appear hypo-intense on the SWI image. Such artefacts can lead to problems in the assessment of important vascular structures located in or near these regions of high phase gradients, e.g. in brain regions surrounding the sinuses. Here we demonstrate that combining a post-processing technique that reduces the high phase gradient artefacts present in SWI images.

Ferdinand Schweser^1,2, Devika Rattan¹, Jesper Hagemeier¹, Paul Polak¹, Michael G Dwyer¹, Christopher R Magnano¹, and Robert Zivadinov^1,2
1Buffalo Neuroimaging Analysis Center, Dept. of Neurology, School of Medicine and Biomedical Sciences, State University of New York at Buffalo, Buffalo, NY, United States, ²MRI Molecular and Translational Imaging Center, Buffalo CTRC, State University of New York at Buffalo, Buffalo, NY, United States

In this work we investigate for the first time magnetic susceptibility of the thalamic nuclear groups in patients with multiple sclerosis (MS). Visibility of thalamic nuclei on susceptibility maps considerably varied between subjects, with highest visibility in CIS and lowest visibility in SP-MS patients. These results challenge current analysis strategies, which consider basal ganglia nuclei as homogeneous structures. Careful analysis of susceptibility in sub-nuclear groups promises to provide more specific information on pathology-related tissue changes.

Arnold Moya Evia Jr.¹, David A Bennett^2,3, Julie A Schneider^2,3, Aikaterini Kotrotsou⁴, Robert J Dawe², and Konstantinos Arfanakis^1,2
1Illinois Institute of Technology, Chicago, Illinois, United States, ²Rush Alzheimer's Disease Center, Illinois, United States, ³Rush University Medical Center, Illinois, United States,⁴MD Anderson Cancer Center, Texas, United States

The relationship between magnetic susceptibility and age-related neuropathology, specifically TDP43, hippocampal sclerosis, and Alzheimer's Disease was explored. Associations with neuropathologic correlates and magnetic susceptibility were found.

Johannes Lindemeyer¹, Ana-Maria Oros-Peusquens¹, Kathrin Reetz^1,2, and N. Jon Shah^1,2
1Institute of Neuroscience and Medicine 4, INM-4, Medical Imaging Physics, Forschungszentrum Jülich GmbH, Jülich, Germany, ²Faculty of Medicine, Department of Neurology, RWTH Aachen University, JARA, Aachen, Germany

This abstract describes a study investigating and quantifying the effect of Parkinson’s disease on the magnetic susceptibility observed in regions of the central brain, measured with a clinical protocol at 3T. The analysis workflow includes customized field map estimation, background field correction and susceptibility reconstruction.

Mathieu David Santin^1,2, Alexandra Petiet^1,2, Elodie Laffrat^1,2, Stéphane Lehéricy^1,2, Chantal François², and Stéphane Hunot^2
1Centre de NeuroImagerie de Recherche (CENIR), Paris, France, ²Institut du Cerveau et de la Moelle épinière, Inserm U 1127, CNRS UMR 7225, Sorbonne Universités, UPMC Univ Paris 06 UMR S 1127, Paris, France

Brain QSM at ultra high field in a primate model of Parkinson's disease

Xu Li^1,2, Hongjun Liu^1,2, Richard P. Allen³, Christopher J. Earley³, Richard A.E. Edden^1,2, Peter B. Barker^1,2, Tiana E. Cruz³, and Peter C.M. van Zijl^1,2
1F.M. Kirby Research Center, Kennedy Krieger Institute, Baltimore, MD, United States, ²Radiology, Johns Hopkins University School of Medicine, Baltimore, MD, United States,³Neurology, Johns Hopkins University School of Medicine, Baltimore, MD, United States

Quantitative susceptibility mapping (QSM) at 7T was utilized to assess brain iron levels in restless legs syndrome (RLS) (aka Willis Ekbom disease), using the measured tissue magnetic susceptibility as an iron index. Data collected on 30 RLS patients and 26 age-matched normal controls showed significantly decreased magnetic susceptibility in RLS patients as compared to controls in dentate nucleus and thalamus. Similar findings were confirmed by a voxel-based analysis, which suggests that substructures such as the sub-thalamic nuclei may also be affected by iron deficiency in RLS.

Deqiang Qiu¹, Fadi Nahab², and Seena Dehkharghani^1
1Radiology and Imaging Sciences, Emory University, Atlanta, GA, United States, ²Neurology, Emory University, GA, United States

In this paper, we studied the venous blood oxygenation using quantitative susceptibility mapping in a group of patients with chronic stenosis in the internal carotid and/or the middle cerebral arteries. We evaluated the baseline venous oxygenation level as well as after acetazolamide (Diamox) challenge.

Huan Tan¹, Tian Liu², Yi Wang³, and Robert R. Edelman^4,5
1Surgery, University of Chicago, Chicago, IL, United States, ²MedImageMetric LLC, New York, NY, United States, ³Radiology, Weill Cornell Medical College, New York, NY, United States, ⁴Radiology, NorthShore University HealthSystem, Evanston, IL, United States, ⁵Radiology, Northwestern University Feinberg School of Medicine, Chicago, IL, United States

In this study we tested the feasibility of applying quantitative susceptibility mapping (QSM) to quantify vascular calcification in patients with peripheral vascular diseases. The preliminary result has demonstrated the capability of using QSM for in-vivo measurements of the diamagnetic susceptibility associated with vascular calcifications.

sakshi khurana¹, Rakesh Kumar Gupta¹, Mukta Kapila², Swati Mittal², Manavita Mahajan², Ritu Tyagi¹, and kirti verma^1
1Radiology, fortis memorial research institute, Gurgaon, Haryana, India, ²gynaecology, fortis memorial research institute, Gurgaon, Haryana, India

Susceptibility weighted with phase imaging is a useful technique in definitive characterization of various stages of blood as well as in calcification in brain; however it has never been used in the evaluation of female pelvis. We studied various pelvic lesions on 3 Tesla MRI scanner and quantified the phase value. Due to the differential para- and di-magnetic nature of calcification and various stages of hemorrhage significant quantitative difference in phase values was seen. With no additional scan time, valuable information obtained from phase MR imaging can give a definitive answer for characterization of various pelvic pathologies in females.