Frédéric Grouiller¹, Joao Jorge^2,3, Francesca Pittau⁴, Wietske van der Zwaag ^5,6, Christoph M Michel⁷, Serge Vulliémoz ⁴, Rolf Gruetter², Maria I Vargas⁸, and François Lazeyras^1
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.

Prantik Kundu^1,2, Lara V. Marcuse³, Bradley Delman¹, Rebecca Feldman¹, Madeline C. Fields³, and Priti Balchandani^1
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. 

Ilaria Boscolo Galazzo^1,2, Silvia Francesca Storti³, Anna Barnes¹, Enrico De Vita⁴, Francesca Benedetta Pizzini², John Duncan⁵, Ashley Groves¹, Gloria Menegaz³, and Francesco Fraioli^1
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.

Lalit Gupta¹, Rakesh K Gupta², Prativa Sahoo¹, Pradeep K Gupta², Rana Patir³, Sandeep Vaishya³, Indrajit Saha⁴, and Walter Backes^5
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. 

Barbara Dymerska¹, Pedro Cardoso¹, Nina Mahr², Eva Matt², Florian Fischmeister², Roland Beisteiner², Siegfried Trattnig¹, and Simon Daniel Robinson^1
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 (TE_local) 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 TE_local 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 TE_local·tSNR.

Gopikrishna Deshpande^1,2,3, D Rangaprakash¹, Wenjing Yan¹, Jeffrey S Katz^1,2,3, Thomas S Denney^1,2,3, and Michael N Dretsch^4,5
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.

Lalit Gupta¹, Rakesh K Gupta², Pradeep K Gupta², Hardeep Singh Malhotra³, Indrajit Saha⁴, and Ravindra K Garg^3
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.

yue cheng¹, Li-xiang Huang¹, Shuang-shuang Xie¹, Tian-yi Qian², and Wen Shen^1
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.

Pradyumna Lanka¹, D Rangaprakash¹, and Gopikrishna Deshpande^1,2,3
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.

Chiao-Chi Chen¹, Yi-Hua Hsu¹, Yi-Jen Peng², Guo-Shu Huang³, and Chen Chang^1
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.