Se-Hong Oh¹, Wanyong Shin¹, and Mark J Lowe^1
1Imaging Institute, Cleveland Clinic Foundation, Cleveland, OH, United States

Due to the much higher specific absorption rate (SAR) of tissue at ultra-high field (UHF), the acquisition time of MT imaging at UHF is much longer than at lower filed strengths. Thus, MT imaging at UHF MRI has not, heretofore been suitable for clinical scanning. In this work, we described a new MT acquisition technique within a clinically reasonable time (<6 min) which uses a sparsely applied MT pulse. With new proposed MT acquisition scheme, the scan time is reduced considerably while maintaining similar MTR when compared with the case of conventional MT.

Andreas Fehlner¹, Kaspar-Josche Streitberger^1,2, Friedemann Paul^3,4, Jens Würfel^3,5, Jürgen Braun⁶, and Ingolf Sack^1
1Department of Radiology, Charité - Universitätsmedizin Berlin, Berlin, Germany, ²Department of Neurology with experimental Neurology, Charité - Universitätsmedizin Berlin, Berlin, Germany, ³NeuroCure Clinical Research Center, Charité - Universitätsmedizin Berlin, Berlin, Germany, ⁴Clinical and Experimental Multiple Sclerosis Research Center, Department of Neurology, Charité - Universitätsmedizin Berlin, Berlin, Germany, ⁵Institute of Neuroradiology, Universitätsmedizin Göttingen, Göttingen, Germany, ⁶Institute of Medical Informatics, Charité - Universitätsmedizin Berlin, Berlin, Germany

High resolution multifrequency MR elastography (MMRE) was applied to patients with clinical isolated syndrome (CIS) in order to test if white matter viscoelasticity is significantly affected by a single neurological episode of inflammation or demyelination. On average, we observed a significant reduction of the magnitude of the complex shear modulus (~11%, p = 0.001) in 17 CIS patients compared to healthy controls. This study complements previous findings on the gradual mechanical degradation of brain tissue associated with multiple sclerosis and raises the prospect of using MMRE as an early marker of neuroinflammation and demyelination.

Bryson Dietz¹, David A Rudko², Marcelo Kremenchutzky³, and Ravi S Menon^1,4
1Centre for Functional and Metabolic Mapping, Robarts Research Institute, Western University, London, ON, Canada, ²Montreal Neurological Institute, McGill University, Montreal, QC, Canada, ³London Health Sciences Centre, London, ON, Canada, ⁴Department of Medical Biophysics, Western University, London, ON, Canada

Longitudinal ultra-high field MR imaging was conducted on 16 relapse remitting multiple sclerosis (RRMS) patients, along with 16 age-matched controls. Lesions were investigated temporally using quantitative susceptibility mapping (QSM) and R2* quantitative imaging. For ringed lesions, we upsampled the image and separated the ring from the inner lesion core, to evaluate each separately. We found that lesion ring and inner core behave similarly over time, which indicates they both respond similarly to biological changes occurring within the tissue. We found R2* to slowly decrease as lesions form, whereas QSM has a sudden jump in susceptibility.

Céline Louapre^1,2, Sindhuja T Govindarajan¹, Costanza Giannì^1,2, Jacob A Sloane³, RP Kinkel⁴, and Caterina Mainero^1,2
1AA. Martinos Center for Biomedical Imaging, Charlestown, MA, United States, ²Harvard Medical School, Boston, MA, United States, ³Beth Israel Deaconess Medical Center, Boston, MA, United States, ⁴University of California San Diego, San Diego, CA, United States

We investigate 7 T T₂* relaxation rates in the cortex of subjects with multiple sclerosis (MS) to determine: 1) quantitative T₂* changes in and beyond visible focal cortical lesions (CL), 2) the spatial distribution of focal MS CL across the cortex, 3) the impact of focal CL on the surrounding peri-lesional cortex. MS focal CL exhibit longer T₂* than healthy cortex. Quantitative T₂* changes extend beyond visible CL in progressive MS. Cortical lesions, however, have the same impact on surrounding peri-lesional cortex across disease stages.

Gabriel Mangeat^1,2, Sindhuja Tirumalai Govindarajan², Revere Philip Kinkel³, Caterina Mainero^2,4, and Julien Cohen-Adad^1,5
1Institute of Biomedical Engineering, Polytechnique Montreal, Montreal, Qc, Canada, ²Martinos Center for Biomedical Imaging, MGH, Charlestown, MA, United States, ³Clinical Neurosciences, University of California San Diego, La Jolla, CA, United States, ⁴Harvard Medical School, Boston, MA, United States,⁵Functional Neuroimaging Unit, CRIUGM, Université de Montréal, Montreal, Qc, Canada

We introduce a multivariate statistical framework for combining cortical sampling of MTR and T₂* to gain specificity for mapping cortical myelin content. (i) We sampled cortical MTR and T₂* from Freesurfer segmentation. (ii) we normalized MTR and T₂* maps and corrected them for partial volume effect and B0 orientation. (iii) we extracted the shared myelin information using a spatial independent component analysis. We demonstrate the benefits of this framework for separating healthy controls from subject with multiple sclerosis on the basis of cortical pathology.

Jing Zhang¹, Irene Vavasour¹, Shannon Kolind², Baumeister Baumeister³, Alexander Rauscher¹, and Alex L. MacKay^1,4
1Department of Radiology, University of British Columbia, Vancouver, BC, Canada, ²Division of Neurology, Department of Medicine, University of British Columbia, Vancouver, BC, Canada, ³Department of Electrical and Computer Engineering, University of British Columbia, Vancouver, BC, Canada,⁴Department of Physics and Astronomy, University of British Columbia, Vancouver, BC, Canada

Myelin water fraction (MWF) is conventionally measured using the T2 decay curve.In this work, GRASE T2 decay curves were performed with different TEs and numbers of echoes for six healthy subjects. These sequences permit more applications for myelin water imaging in clinical studies and neuroscience.

Dana Cobzas¹, Hongfu Sun¹, Andrew J. Walsh¹, R. Marc Lebel¹, Gregg Blevins², and Alan H. Wilman^1
1Biomedical Engineering, University of Alberta, Edmonton, Alberta, Canada, ²Neurology, University of Alberta, Edmonton, Alberta, Canada

Quantitative Susceptibility Mapping (QSM) and R2* mapping studies of subcortical grey matter have generally analyzed large regions-of-interest that do not supply precise location of iron accumulation. Large regions have been used partly due to the difficulty of accurate segmentation of deep grey matter. Here we develop a focused deep grey nuclei atlas using combined QSM and T1-weighted images and investigate its precision and reliability for voxel-based subcortical grey matter analysis using R2* and QSM. We then apply our method to multiple sclerosis to determine local effects of iron accumulation in subcortical grey matter nuclei.

Elisabetta Pagani¹, Maria A. Rocca^1,2, Alvino Bisecco¹, Olga Ciccarelli³, Christian Enzinger⁴, Antonio Gallo⁵, Hugo Vrenken⁶, Maria Laura Stromillo⁷, Tarek A. Yousry³, Franz Fazekas⁴, Gioacchino Tedeschi⁵, Frederik Barkhof⁶, Nicola De Stefano⁷, Massimo Filippi^1,2, and the MAGNIMS Network^8
1Neuroimaging Research Unit, Institute of Experimental Neurology, Division of Neuroscience, San Raffaele Scientific Institute, Vita-Salute San Raffaele University, Milan, MI, Italy, ²Department of Neurology, San Raffaele Scientific Institute, Vita-Salute San Raffaele University, Milan, MI, Italy, ³UCLH NHS Foundation Trust, National Hospital for Neurology and Neurosurgery, London, UK, United Kingdom, ⁴Department of Neurology, Medical University of Graz, Graz, A, Austria, ⁵MRI Center “SUN-FISM", Second University of Naples, Naples, NA, Italy, ⁶Department of Radiology, VU University Medical Centre, Amsterdam, Netherlands, Netherlands, ⁷Department of Neurological and Behavioral Sciences, University of Siena, Siena, SI, Italy, ⁸EU, EU, Italy

Single center studies have shown an association between disrupted white matter architectural integrity and clinical manifestations, including cognitive impairment, in multiple sclerosis (MS). In this study, we applied voxel wise analysis of diffusion tensor derived metrics in data obtained in a multi-center setting to assess the spatial distribution of white matter damage in MS and its relationship with cognitive impairment. We found significant differences comparing cognitive impaired with cognitive preserved patients and correlations with cognitive tests. We concluded that this approach is feasible in a multi-center setting and it contributes to better characterize disease related cognitive manifestations.

Adil Maarouf^1,2, Bertrand Audoin¹, Anthony Faivre¹, Francoise Reuter¹, Fanelly Pariollaud¹, Audrey Rico¹, Elisabeth Soulier¹, Sylviane Confort-Gouny¹, Maxime Guye¹, Lothar Schad³, Jean Pelletier¹, Jean-Philippe Ranjeva¹, and Wafaa Zaaraoui^1
1CRMBM UMR CNRS 7339 Aix-Marseille Université, Marseille, France, ²Faculté de Médecine, Université de Reims Champagne-Ardenne, Reims, France,³Computer Assisted Clinical Medicine, Heidelberg University, Mannheim, Germany

This study aimed to assess brain sodium accumulation in cognitive MS. Fifty-eight patients and 31 controls were included in a sodium MRI study performed at 3T. Total sodium concentration (TSC) was increased in cognitive MS patients compared to non-cognitive MS patients and controls. These sodium accumulations were located in the cingulate cortex, precuneus, temporal and prefrontal cortices, independently of atrophy. In cognitive MS, sodium accumulation, which is an indicator of neuronal injury, affects the neocortex (involved in higher functions). Sodium MRI is able to depict neuronal injury, very early in the disease, before the occurrence of atrophy.

Qun He¹, Lanqing Ma¹, Wen Hong^1,2, Vipul Sheth¹, Graeme M Bydder¹, and Jiang Du^1
1Radiology, UC, San Diego, San Diego, CA, United States, ²Radiology, China-Japan friendship hospital, Beijing, Beijing, China

IR-UTE sequence was employed to generate high contrast magnitude and phase images of the previously undetected short T2 components in white matter of the brain in vivo using a clinical 3T scanner.