ISMRM 24th Annual Meeting & Exhibition • 07-13 May 2016 • Singapore

Scientific Session: fMRI in Disease

Monday, May 9, 2016
Room 331-332
16:30 - 18:30
Moderators: Qiyong Gong, Jie Tian

Presurgical brain mapping in epilepsy using simultaneous EEG and functional MRI at ultra-high field: feasibility and first results
Frédéric Grouiller1, Joao Jorge2,3, Francesca Pittau4, Wietske van der Zwaag 5,6, Christoph M Michel7, Serge Vulliémoz 4, Rolf Gruetter2, Maria I Vargas8, and François Lazeyras1
1Department of Radiology and Medical Informatics, University of Geneva, Geneva, Switzerland, 2Laboratory for Functional and Metabolic Imaging, Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland, 3Institute for Systems and Robotics, Department of Bioengineering, Instituto Superior Técnico, University of Lisbon, Lisbon, Portugal, 4EEG and Epilepsy Unit, Department of Neurology, Geneva University Hospital, Geneva, Switzerland, 5Biomedical Imaging Research Center (CIBM), Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland, 6Spinoza Centre for Neuroimaging, Amsterdam, Netherlands, 7Functional Brain Mapping Laboratory, Department of Fundamental Neurosciences, University of Geneva, Geneva, Switzerland, 8Division of Neuroradiology, Geneva University Hospital, Geneva, Switzerland
The aim of this study was to demonstrate that EEG can be used safely at ultra-high field to locate epileptic focus and functional eloquent cortex in patients. We recorded simultaneous EEG-fMRI at 7T in 9 patients. Despite large artifacts in intra-MRI EEG recordings, it was possible to detect interictal epileptiform discharges and to perform noise-sensitive topography-related analyses. Using an optimized setup and appropriate artifact removal algorithms, localization of epileptic networks and of functional eloquent cortex is possible at ultra-high field. Therefore, the increased fMRI sensitivity offered by this technology may be beneficial to improve presurgical evaluations of patients with epilepsy.

High-Frequency and Other Pathological Network Hemodynamics Observed in Epilepsy Patients Imaged With Multi-Band Multi-Echo BOLD Functional MRI at 7T
Prantik Kundu1,2, Lara V. Marcuse3, Bradley Delman1, Rebecca Feldman1, Madeline C. Fields3, and Priti Balchandani1
1Department of Radiology, Icahn School of Medicine at Mt. Sinai, New York, NY, United States, 2Department of Psychiatry, Icahn School of Medicine at Mt. Sinai, New York, NY, United States, 3Department of Neurology, Icahn School of Medicine at Mt. Sinai, New York, NY, United States
Clinical assessment of epilepsy based on extra-cranial EEG electrophysiology has moderate diagnostic sensitivity (40%), poor spatial specificity (1-5 cm), and no prognostic value. We seek to utilize MRI for more effective non-invasive characterization of epilepsy than currently established. We implemented multi-echo multi-band (MEMB) BOLD fMRI at 7T to map the hemodynamic signatures of seizure zones and networks in spontaneous brain activity of focal epilepsy patients versus matched controls. We mapped seizure networks in patients at millimeter-resolution, and observed epileptiform BOLD to have significantly amplified infra-slow and high-frequency temporal oscillations, analogous to characteristic epileptiform activity from EEG. 

Mapping resting state networks in epilepsy with Arterial Spin Labeling connectivity analysis
Ilaria Boscolo Galazzo1,2, Silvia Francesca Storti3, Anna Barnes1, Enrico De Vita4, Francesca Benedetta Pizzini2, John Duncan5, Ashley Groves1, Gloria Menegaz3, and Francesco Fraioli1
1Institute of Nuclear Medicine, University College London, London, United Kingdom, 2Department of Neuroradiology, University Hospital Verona, Verona, Italy, 3Department of Computer Science, University of Verona, Verona, Italy, 4Department of Brain Repair and Rehabilitation, UCL Institute of Neurology, London, United Kingdom, 5Department of Clinical and Experimental Epilepsy, UCL Institute of Neurology, London, United Kingdom
In this study, we propose the assessment of resting-state brain networks (RSNs) using Arterial Spin Labeling perfusion MRI as an alternative to the gold-standard sequence represented by the Blood-oxygenation-level-dependent (BOLD) contrast. RSNs have been derived by means of independent component analysis (ICA) and spatially compared to literature networks. In addition, functional connectivity changes in epileptic patients have been quantified in comparison to healthy controls. The results demonstrated ASL suitability in identifying RSNs, with a strong agreement with BOLD, and in detecting functional alterations in pathological conditions.

BOLD Hemodynamic alteration in Brain Tumors
Lalit Gupta1, Rakesh K Gupta2, Prativa Sahoo1, Pradeep K Gupta2, Rana Patir3, Sandeep Vaishya3, Indrajit Saha4, and Walter Backes5
1Philips India Ltd., Bangalore, India, 2Department of Radiology, Fortis Memorial Research Institute, Gurgaon, India, 3Department of Neurosurgery, Fortis Memorial Research Institute, Gurgaon, India, 4Philips India Ltd., Gurgaon, India, 5Department of Radiology, Maastricht University Medical Center, Maastricht, Netherlands
The objective of the study is to determine the temporal delay in cerebral hemodynamic flow in brain tumors relative to normal brain tissue using rsfMRI and compare this with DCE derived cerebral blood volume(CBV) maps. Time series from all the voxels were cross-correlated with the mean time series from the normal hemisphere. The time point with maximum correlation was used to generate temporal shift map(TSM) for each voxel. We observed early hemodynamic changes in high grade glioma and found significant difference in the mean TSM ratio between Glioblastoma(GBM) and low grade tumors. TSM also appeared similar to rCBV perfusion maps. 

Investigating the impact of temporal signal fluctuations and local effective echo times on indices of BOLD sensitivity in healthy subjects and tumor patients at 7T.
Barbara Dymerska1, Pedro Cardoso1, Nina Mahr2, Eva Matt2, Florian Fischmeister2, Roland Beisteiner2, Siegfried Trattnig1, and Simon Daniel Robinson1
1High Field MR Centre, Department of Biomedical Imaging and Image-guided Therapy, Medical University of Vienna, Vienna, Austria, 2High Field MR Centre, Department of Neurology, Medical University of Vienna, Vienna, Austria
Temporal signal fluctuations (tSNR) and local effective echo time (TElocal) are explored and their influence on BOLD sensitivity is investigated at 7T for healthy subjects and tumor patients, where prominent spatial variations in those two measures are expected. We show that tSNR may indicate sufficient sensitivity to detect activation but that BOLD sensitivity may be dramatically reduced by changes in TElocal close to pathologies and vital brain functions (motor, speech, auditory). Neglecting local TE variations can thus lead to false negative results in clinical fMRI. We thus suggest a new BOLD sensitivity metric based on TElocal·tSNR.

Hemodynamic Alterations in Posttraumatic Stress Disorder and Mild Traumatic Brain Injury
Gopikrishna Deshpande1,2,3, D Rangaprakash1, Wenjing Yan1, Jeffrey S Katz1,2,3, Thomas S Denney1,2,3, and Michael N Dretsch4,5
1AU MRI Research Center, Department of Electrical and Computer Engineering, Auburn University, Auburn, AL, United States, 2Department of Psychology, Auburn University, Auburn, AL, United States, 3Alabama Advanced Imaging Consortium, Auburn University and University of Alabama Birmingham, Birmingham, AL, United States, 4U.S. Army Aeromedical Research Laboratory, Fort Rucker, AL, United States, 5Human Dimension Division, HQ TRADOC, Fort Eustis, VA, United States
Functional MRI is an indirect measure of neural activity, as it is the convolution of the hemodynamic-response function (HRF) and a latent neural response. Recent studies show variance in HRF across brain regions and subjects. This raises the question of reliability of fMRI results if, for example, a canonical HRF is used in analysis. Using whole-brain resting-state fMRI, we employed blind hemodynamic deconvolution to estimate HRF parameters. We uncovered hemodynamic alterations in Soldiers with PTSD and mTBI, and found that certain subcortical and default-mode network regions showed significant alterations in HRF.

Assessment of brain cognitive functions in patients with vitamin B12 deficiency using resting state functional MRI
Lalit Gupta1, Rakesh K Gupta2, Pradeep K Gupta2, Hardeep Singh Malhotra3, Indrajit Saha4, and Ravindra K Garg3
1Philips India Ltd., Bangalore, India, 2Department of Radiology, Fortis Memorial Research Institute, Gurgaon, India, 3Department of Neurology, King George Medical University, Lucknow, India, 4Philips India Ltd., Gurgaon, India
The alterations in the brain cognitive functions due to vitamin B12 deficiency and reversibility of these alterations following therapy was studied using resting state fMRI. Regional Homogeneity (ReHo) was used to assess functional changes in patients with vitamin B12 deficiency. ReHo was significantly lower in patients than controls in the entire cerebrum and in the brain networks associated with cognition control i.e. default mode, cingulo-opercular and fronto-parietal network. We conclude that the brain networks associated with cognition control, in particular pre-frontal regions, are altered in patients with vitamin B12 deficiency that partially recovered following six weeks of replacement therapy.

Longitudinal Changes in Intrinsic Brain Activity in Cirrhotic Patients Before and One Month After Liver Transplantation
yue cheng1, Li-xiang Huang1, Shuang-shuang Xie1, Tian-yi Qian2, and Wen Shen1
1Tianjin First Central Hospital, Tianjin, China, People's Republic of, 2Siemens Healthcare, MR Collaborations NE Asia, Beijing, China, People's Republic of
In this study, we evaluated brain activity changes in cirrhotic patients referred for liver transplantation (LT). Twenty cirrhotic patients and 25 healthy controls were included. Amplitude of low-frequency fluctuation (ALFF) values were compared between cirrhotic patients (pre- and post-LT) and healthy controls as well as patients pre- and post-LT. In cirrhotic patients, decreased ALFF in most brain regions can be reversed one month after LT, and the increased ALFF in temporal and frontal lobe may also return to normal. The reduced ALFF in the right supplementary motor area, inferior parietal lobule and calcarine persisted. One month after LT, the spontaneous brain activity partially renormalized, but complete cognitive function restoration may need a longer time.

Perils in the Use of Cross-validation for Performance Estimation in Neuroimaging-based Diagnostic Classification
Pradyumna Lanka1, D Rangaprakash1, and Gopikrishna Deshpande1,2,3
1AU MRI Research Center, Department of Electrical and Computer Engineering, Auburn University, Auburn, AL, United States, 2Department of Psychology, Auburn University, Auburn, AL, United States, 3Alabama Advanced Imaging Consortium, Auburn University and University of Alabama, Birmingham, AL, United States
In this study, we highlight the fact that cross-validation accuracy might not be a good measure of performance estimation in neuroimaging-based diagnostic classification, especially with smaller sample sizes typically encountered in neuroimaging. We trained an array of classifiers using resting state fMRI-based functional connectivity measures from subjects in a particular age group using cross-validation, and then tested on an independent set of subjects with the same diagnosis (mild cognitive impairment and Alzheimer’s disease), but from a different age group. We demonstrate that cross-validation accuracy might give us an inflated estimate of the true performance of the classifiers.

fMRI indicates central TRPV1 modulation on gouty pain
Chiao-Chi Chen1, Yi-Hua Hsu1, Yi-Jen Peng2, Guo-Shu Huang3, and Chen Chang1
1Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan, 2Department of Pathology, Tri-Service General Hospital, National Defense Medical Center, Taipei, Taiwan, 3Department of Radiology, Tri-Service General Hospital, National Defense Medical Center, Taipei, Taiwan
Gout is one of the most painful forms of diseased conditions. Non-steroid anti-inflammatory drugs and colchicine are first-line agents for the acute attack, but these drugs are poorly tolerated or contraindicated in some patients. Elucidating the pain signaling pathway of gout may shed light on the key molecules that may be pursued as therapy targets in the future. Our neuroimaging, cellular, and molecular investigations regarding transient receptor potential vanilloid 1 (TRPV1) reveal a novel transduction pathway from the periphery to the brain during the attack of gout.

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