Clinical Diffusion
Click on to view the abstract pdf. Click on to view the recorded presentation.
Thursday 10 May 2012
Room 201  16:00 - 18:00 Moderators: Alexander Leemans, Carlo Pierpaoli

16:00 0644.   Altered White Matter Microstructure for Cognitive Impairment Associated with First-episode Drug-naïve Late-onset Depression: A 6-month Follow-up Study with Diffusion Tensor Imaging
Daniel Han-en Chang1, Huali Wang2,3, Na Zhang2,3, Huishu Yuan4, Xin Yu2,3, L. Tugan Muftuler5, and Min-Ying Su1
1Tu & Yuen Center for Functional Onco-Imaging, Department of Radiological Sciences, University of California, Irvine, CA, United States, 2Dementia Care and Research Center, Peking University Institute of Mental Health, Beijing, China, 3Key Laboratory for Mental Health, Ministry of Health (Peking University), Beijing, China, 4Department of Radiology, Peking University Third Hospital, Beijing, China, 5Department of Neurosurgery and Biophysics, Medical College of Wisconsin, Milwaukee, WI, United States

A significant portion of elderly patients with late-onset depression (LOD) are cognitively impaired. However, a number LOD patients do not have sustained cognitive impairment after remission following treatment, and thus it may be possible that neuroimaging can differentiate between these patients by examining the underlying affected neural pathways. FSL's tract-based spatial statistics was used to compare FA and MD values in a voxel-wise manner among cognitively-impaired LOD subjects, cognitively-normal LOD subjects, and normal control subjects. Cognitively-impaired LOD subjects were found to have decreased FA and increased MD values when compared to both cognitively-normal LOD subjects and normal control subjects.

16:12 0645.   
Assessment of White Matter Integrity in Mild Cognitive Impairment and Alzheimer’s Disease
Els Fieremans1, Jens H Jensen1,2, Rachael L Deardorff2, Amanda Allen2, Jane Kwon1, Ali Tabesh2, Maria F Falangola2, Steven H Ferris1, and Joseph A Helpern2
1Center for Biomedical Imaging, Radiology, New York University School of Medicine, New York, NY, United States, 2Radiology and Radiological Science, Medical University of South Carolina, Charleston, SC, United States

White matter microstructure in patients with mild cognitive impairment (MCI) and in patients with Alzheimer’s Disease (AD) is characterized and compared to results for age-matched normal controls (NC), by applying tract-based spatial statistics together with recently proposed specific measures of white matter integrity as derived from diffusional kurtosis imaging. The radial extra-axonal diffusivity was most sensitive in discriminating MCI from NC, while the axonal water fraction was most sensitive in discriminating MCI from AD. These results support a hypothesis that demyelination and axonal loss are key neurodegenerative processes describing conversion from NC to MCI and from MCI to AD, respectively.

16:24 0646.   
Globally impaired network of anatomical connectivity in tuberous sclerosis complex patients with autism spectrum disorders
Benoit Scherrer1, Mustafa Sahin1, Caterina Stamoulis1, Sanjay P Prabhu1, Alireza Akhondi-Asl1, and Simon K Warfield1
1Radiology, Harvard Medical School, Children Hospital Boston, Boston, MA, United States

This study is to our knowledge the first to investigate with diffusion imaging the network of anatomical connectivity in tuberous sclerosis complex (TSC) patients and its relationship to autism spectrum disorder (ASD). Our results suggest that the network is globally significantly affected in TSC patients with ASD.

16:36 0647.   Restriction Spectrum Imaging of Glioblastoma Multiform: Comparison vs. ADC.
Nathan White1, Joshua Kuperman1, Carrie McDonald2, Nikdokht Farid1, Santosh Kasari3, Ajit Shankaranarayanan4, and Anders Dale1,5
1Department of Radiology, University of California, San Diego, La Jolla, CA, United States, 2Department of Psychiatry, University of California, San Diego, La Jolla, CA, United States, 3Department of Neuro-Oncology, University of California, San Diego, La Jolla, CA, United States, 4GE Healthcare, Inc,5Department of Neuroscience, University of California, San Diego

Diffusion-weighted MRI (DW-MRI) offers a unique perspective on tumor pathology by probing the microscopic diffusion properties of neoplastic tissue at the cellular and subcellular level. In this study, we evaluate the utility of a newly developed advanced DW-MRI approach called “Restriction Spectrum Imaging” (RSI) to probe tumor microenvironments in terms of a “spectrum” of hindered and restricted water compartments. We derive a “cellularity index” using the spherically restricted spectral components and demonstrate its improved sensitivity and specificity in identifying tumor vs. healthy tissue in patients with glioblastoma multiform (GBM) compared to the apparent diffusion coefficient (ADC).

16:48 0648.   Cerebral microbleeds: A study on white matter tract integrity and cognition
Ai Wern Chung1, Bhavini Patel1, Andrew J. L. Lawrence1, Philip Rich2, Andrew MacKinnon2, Robin G. Morris3, Hugh S. Markus1, and Thomas R. Barrick1
1Stroke and Dementia Unit, St George's University of London, London, London, United Kingdom, 2Neuroradiology, St George's Hospital, London, United Kingdom, 3Department of Psychology, Institute of Psychiatry, London, United Kingdom

Cerebral microbleeds (CMB) are hemosiderin deposits in the brain and are a feature of small vessel disease (SVD). To date, there are conflicting results on the association between CMB and cognitive function. Using region-of-interest and tractography analysis, we compared diffusion tensor measures in white matter local and distal to CMB in SVD patients. We found no relationship between the absence/presence, and number of CMB with cognition. Additionally, diffusion measures showed no significant change in white matter in the region of CMB. Our results suggest CMB are not detrimental to white matter integrity nor associated with cognitive function in SVD patients.

17:00 0649.   GRAPPA-accelerated dual-echo diffusion-weighted EPI with intensity correction
Samantha J Holdsworth1, Stefan Skare2, Matus Straka1,3, Manabu Inoue3, and Roland Bammer1
1Department of Radiology, Stanford University, Palo Alto, CA, United States, 2Clinical Neuroscience, Karolinska Institute, Stockholm, Sweden, 3Stanford Stroke Center, Stanford University Medical Center, Stanford University, Palo Alto, CA, United States

Geometric distortion in single-shot (ss)-EPI used for diffusion-weighted imaging (DWI) can be reduced through the use of parallel imaging, however the shorter TE results in images which can have lower lesion sensitivity. Thus, to benefit from both increased image quality through the use of parallel imaging as well as the increased sensitivity of lesions through higher echo times, here we implement a GRAPPA-accelerated dual-echo EPI DWI sequence on stroke patients and present our preliminary data. We also demonstrate how one can utilize the two echoes to remove the coil sensitivity which removes the need for an additional calibration scan.

17:12 0650.   
Increased FA in acute TBI rat Marmarau model followed by decreased FA during subacute stage: A TBSS study
Ramtilak Gattu1, Randall R Benson2,3, Zhifeng Kou4, Nisrine Zakaria5, Srinivasu Kallakuri5, Yimin Shen6, John M Cavanaugh5, Hardik J Doshi5, and Ewart M Haacke7
1Radiology, Wayne State university School of Medicine, Novi, Michigan, United States, 2Neurology, Wayne State university School of Medicine, 3Center for Neurological studies, Novi, MI, United States, 4Radiology and Biomedical Engg, Wayne State university, 5Biomedical Engineering, Wayne State university, 6Radiology, Wayne State university School of Medicine, 7Radiology and Biomedical Engg, Wayne State university School of Medicine

With the current study, our objective is to establish an advanced MR imaging-based version of the Marmarou rodent model of diffuse axonal injury.The focus of the current abstract is to examine DTI measures over the entire rat brain pre and post injury and over time (4 hrs to 7 days) to determine the natural history of fractional anisotropy (FA) at hyperacute, acute and subacute stages. Contradictory findings in the literature regarding FA measures acutely (increase vs. decrease) exist, highlighting the importance of controlled longitudinal studies to clarify this and complex issues were studied using TBSS in rats.

17:24 0651.   
Is TBSS more sensitive to Pakinson's Disease pathology than traditional VBM?
Marta Morgado Correia1, Charlotte Rae1, Ellemarije Altena2, Laura Hughes1,2, and James Rowe1,2
1Cognition and Brain Sciences Unit, Medical Research Council, Cambridge, Cambridgeshire, United Kingdom, 2Department of Clinical Neurosciences, University of Cambridge, Cambridge, United Kingdom

In this diffusion MRI study we used TBSS and VBM methods to compare a group of PD patients to an age and gender matched set of controls, and we aimed to determine which of those techniques is most sensitive in detecting white matter changes in Parkinson’s patients. Using TBSS we replicated previous studies and have also shown more widespread cortical white matter pathology in PD. The VBM method found no regions of significantly decreased FA or increased MD in patients that survive FDR correction for multiple comparisons, suggesting that TBSS is more sensitive to white matter changes in PD patients.

17:36 0652.   
Automatic, rapid, non-invasive and precise localization of thalamic nuclei for Deep Brain Stimulation (DBS) surgery using a combination of Diffusion and Functional MRI
Halleh Ghaderi1,2, Abbas Sadikot3, Jennifer Campbell2, and G. Bruce Pike2,3
1Biomedical Engineering, McGill University, Montreal, Quebec, Canada, 2McConnell Brain Imaging Center, Montreal, Quebec, Canada, 3Neurology and Neurosurgery, McGill University, Montreal, Quebec, Canada

Deep brain stimulation (DBS) is a surgical treatment for Parkinson’s disease that involves implanting electrode in thalamus of awake patients. The success of this surgery is highly influenced by the accuracy of target localization. Current DBS planning is limited to visual inspection of anatomical MRI and micro-electrode recording during the surgery to find the target. This may require multiple insertions, thus increasing the risk of complications. Therefore, the conventional target localization is complex, tedious and time-consuming for surgeon and uncomfortable for an awake patient. This study proposes a non-invasive, automatic, rapid technique to accurately localize thalamic nuclei using a combination of Diffusion imaging and functional MRI.

17:48 0653.   Strong correlation between hippocampal volume and integrity of inferior cingulum bundle in patients with mesial temporal lobe epilepsy
Y.C. Shih1,2, C. E. J. Tseng3, H.H. Liou4, P.Y. Chen2, F.H. Lin1, and W.Y. I. Tseng2
1Institute of Biomedical Engineering, National Taiwan University, Taipei, Taiwan, Taiwan, 2Center for Optoelectronic Biomedicine, National Taiwan Univerity College of Medicine, Taipei, Taiwan, Taiwan, 3Biomedical Imaging and Radiological Sciences, National Yang-Ming University, Taipei, Taiwan,4Department of Neurology, National Taiwan University Hospital, Taiwan

Hippocampal sclerosis (HS) is the common abnormality observed in patients with mesial temporal lobe epilepsy (MTLE). MTLE affects the networks of regions that are anatomically connected to the hippocampus. Since the hippocampus is a terminal node of the inferior cingulum bundles (CB), we hypothesized that the integrity of the inferior CB is related to the atrophy of the hippocampus. In this study, we evaluated the integrity of white matter by diffusion spectrum imaging (DSI) and the atrophy of hippocampus by the volume measurement, and investigated their relationship. Strong positive correlation was found in the lesion side of patients with HS.