Normal Brain
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Traditional Poster Normal Brain Exhibition Hall Monday, May 9, 2016: 10:45 - 12:45 1158 Impact of acquisition parameters on cortical thickness and volume derived from Multi-Echo MPRAGE scans Ross W. Mair1,2, Martin Reuter2,3, and Andre J. van der Kouwe2 1Center for Brain Science, Harvard University, Cambridge, MA, United States, 2A.A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Charlestown, MA, United States, 3Department of Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, MA, United States The multi-echo MPRAGE (MEMPRAGE) sequence was implemented to reduce signal distortion by acquiring at a higher bandwidth and averaging multiple echoes to recover SNR while providing additional T2* information that can enhance cortical segmentation. A rapid 2- minute MEMPRAGE protocol has been implemented for large multi-center studies. Here, we investigate the impact on morphometric results for the cortex by systematically varying all the parameters modied between the rapid 2-minute scan and a conventional 6- minute structural scan. Small but signicant diąerences in cortical thickness and gray matter volume result from a combination of the use of partial fourier acquisition and lowering the spatial resolution to 1.2mm. 1159 Quantitative comparison of MP2RAGE skull-stripping strategies Pavel Falkovskiy1,2,3, Bénédicte Maréchal1,2,3, Shuang Yan4, Zhengyu Jin4, Tianyi Qian5, Kieran O'Brien6,7, Reto Meuli2, Jean-Philippe Thiran2,3, Gunnar Krueger2,3,8, Tobias Kober1,2,3, and Alexis Roche1,2,3 1Advanced Clinical Imaging Technology (HC CMEA SUI DI BM PI), Siemens Healthcare AG, Lausanne, Switzerland, 2Department of Radiology, University Hospital (CHUV), Lausanne, Switzerland, 3LTS5, École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland, 4Department of Radiology, Peking Union Medical College Hospital, Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing, China, People's Republic of, 5MR Collaborations NE Asia, Siemens Helathcare, Beijing, China, People's Republic of, 6Centre for Advanced Imaging, University of Queensland, Brisbane, Australia, 7Siemens Healthcare Pty Ltd., Brisbane, Australia, 8Siemens Medical Solutions USA, Boston, MA, United States The MP2RAGE pulse sequence exhibits higher grey-matter/white-matter contrast compared to standard MPRAGE acquisitions and provides images with greatly reduced B1 bias. In theory, these qualities of MP2RAGE should lead to more accurate morphometric results. However, a major hindrance to MP2RAGE morphometric processing is the salt-and-pepper noise in the background and cavities. This poses a major problem for the skull-stripping stage of most automated morphometry algorithms. We investigated three skull- stripping strategies using the MorphoBox prototype and FreeSurfer automated-morphometry software packages and compared them to results obtained using the gold-standard MPRAGE contrast. 1160 Synthetic Quantitative MRI through Relaxometry Modelling for Improved Brain Segmentation Martina F Callaghan1, Siawoosh Mohammadi1,2, and Nikolaus Weiskopf1,3 1Wellcome Trust Centre for Neuroimaging, UCL Institute of Neurology, London, United Kingdom, 2Department of Systems Neuroscience, University Medical Center Hamburg-Eppendorf, Hamburg, Germany, 3Department of Neurophysics, Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany Here we exploit the inter-dependence of quantitative MRI (qMRI) parameters via relaxometry modelling to generate synthetic quantitative maps of magnetisation transfer saturation. The utility of the new concept of synthetic quantitative data is demonstrated by improving image segmentation of deep gray matter structures for neuroimaging applications. 1161 Evaluation of Pairwise and Groupwise Templates-based Approaches for Automated Segmentation of Structures in Brain MR Images Subrahmanyam Gorthi1 and Srikrishnan Viswanathan1 1Samsung R&D Institute, Bangalore, India This work presents a detailed investigation of two multiple-templates based fusion approaches for automated segmentation of structures in the brain MR images: (i) fusion based on direct pairwise registrations between each template and the target image, and (ii) fusion based on an intermediate groupwise template, requiring only a single onsite registration. The key nding from these evaluations is that, if computational time for automated segmentations is a major concern, then groupwise-template based registration followed by fusion is an optimal choice; if time is not a major constraint, then multiple pairwise registrations followed by fusion provides more accurate segmentations. 1162 DR-TAMAS: Diąeomorphic Registration for Tensor Accurate alignMent of Anatomical Structures Mustafa Okan Irfanoglu1,2, Amritha Nayak1,2, Jeąrey Jenkins1,2, Elizabeth B Hutchinson1,2, Neda Sadeghi1, Cibu P Thomas1,3, and Carlo Pierpaoli1 1NICHD, NIH, Bethesda, MD, United States, 2Henry Jackson Foundation, Bethesda, MD, United States, 3CNRM, Bethesda, MD, United States Spatial alignment of diąusion tensor MRI data is of fundamental importance for voxelwise statistical anaysis and creation of population specic atlases of diąusion MRI metrics. In this work, we propose DR-TAMAS, a novel diąusion tensor imaging registration method which uses a spatially varying metric to achieve accurate alignment not in only in white matter but also in gray matter and CSF lled regions. Our tests indicate that DR-TAMAS shows excellent overall performance in the entire brain, while being equivalent to the best existing methods in white matter. 1163 High resolution anatomical imaging of the human occipital lobe with a large ex-vivo 9.4T RF coil Shubharthi Sengupta1, Ron Hellenbrand2, René Finger2, Chris Wiggins3, and Alard Roebroeck1 1Dept. of Cognitive Neuroscience, Faculty of Psychology and Neuroscience, Maastricht University, Maastricht, Netherlands, 2Lab Engineering & Instrumentation Department, Maastricht University, Maastricht, Netherlands, 3Scannexus, Maastricht, Netherlands Small-bore animal scanners or spectroscopy systems have often been used for the investigation of small post-mortem human brain samples. These studies use the high eld strengths and strong gradients, but are inherently limited to very small sample sizes. In this abstract, we discuss the acquisition of very high resolution anatomical images (100μm isotropic) of a full occipital sample as large as 80x80x80 mm3 , using a customised RF receive coil-array in a large-bore 9.4 T human scanner. 1164 Cross-validation of a CSF MRI sequence for calculating brain volume by comparison with brain segmentation methods Lisa A. van der Kleij1, Jeroen de Bresser1, Esben T. Petersen2, Jeroen Hendrikse1, and Jill B. De Vis1 1Department of Radiology, UMC Utrecht, Utrecht, Netherlands, 2Danish Research Centre for Magnetic Resonance, Centre for Functional and Diagnostic Imaging and Research, Copenhagen University Hospital Hvidovre, Hvidovre, Denmark We recently introduced a CSF MRI sequence to automatically measure intracranial volume (ICV) and brain parenchymal volume (BPV). This sequence with short imaging time (0:57 min) and fast post processing correlates well with qualitative brain atrophy scores. This study demonstrates that the low resolution and high resolution CSF MRI sequences perform well in the assessment of BPV and ICV, with a precision similar to the conventional brain segmentation methods FSL, Freesurfer and SPM. The CSF MRI sequence showed a good to very good correlation with the conventional segmentation methods for ICV and BPV. 1165 A 7T Human Brain Microstructure Atlas by Minimum Deformation Averaging at 300μm Andrew L Janke1, Kieran O'Brian2, Steąen Bollmann1, Tobias Kober3, and Markus Barth1 1Centre for Advanced Imaging, University of Queensland, Brisbane, Australia, 2Siemens Healthcare Pty Ltd, Brisbane, Australia, 3Advanced Clinical Imaging Technology, Siemens Healthcare AG, Lausanne, Switzerland 7T provides a method to see detailed image contrast in the human brain; the MP2RAGE sequence allows 500um acquisition resolution. 1166 Evaluating the variability of multicenter and longitudinal hippocampal volume measurements. Stephanie Bogaert1, Michiel de Ruiter2, Sabine Deprez3,4, Ronald Peeters3, Pim Pullens5,6, Frank De Belder6, José Belderbos7, Sanne Schagen2, Dirk De Ruysscher8,9, Stefan Sunaert3,4, and Eric Achten1 1Radiology, Ghent University Hospital, Ghent, Belgium, 2Psychosocial Research and Epidemiology, Netherlands Cancer Institute, Amsterdam, Netherlands, 3Radiology, Leuven University Hospital, Belgium, 4Imaging and Pathology, KU Leuven, Belgium, 5Radiology, University of Antwerp, Belgium, 6Radiology, Antwerp University Hospital, Belgium, 7Radiation Oncology, Netherlands Cancer Institute, Amsterdam, Netherlands, 8Radiation Oncology, MAASTRO clinic Maastricht, Netherlands, 9Respiratory Oncology, Maastricht University Medical Center, Netherlands Longitudinal multicenter MRI studies require stable and comparable measurements. We scanned two subjects in six diąerent scanners (two vendors) at diąerent time points and assessed hippocampal volumes manually and automatically. Intrascanner CV was <2.62% for both techniques; Freesurfer is a good alternative for manual delineation for longitudinal studies. Intervendor variability was sometimes lower than intrascanner variability for the manual technique, which suggests only a modest eąect of hardware diąerences across vendors. Freesurfer results were systematically higher for vendor B compared to A; it is not recommended to compare cross-sectional