The Role of 7T MRI to Assess Atrophy of the Subcortical Deep Gray Matter in Relapsing-remitting Multiple Sclerosis (4184)

Objective: To optimize an automated segmentation method for 7T deep grey matter (DGM) volume quantitation and assess its sensitivity for atrophy detection and relationship to DGM lesions and disability in relapsing-remitting MS (RRMS). Background: DGM atrophy and lesions are important elements of MS pathology. Prior data indicate 7T MRI affords improved DGM lesion detection and volume segmentation versus 3T. Design/Methods: 30 RRMS subjects [age (mean±SD) 44.0±11.3 years, EDSS score 2.0±1.4] and 15 age-/sex-matched healthy controls underwent 7T imaging with 3D MP2RAGE and FLAIR at 0.7 mm3 isotropic voxels, at baseline and 1-year. Applying the FSL-FIRST pipeline, we optimized pre-processing by combining two MP2RAGE inversion times and uniform T1-weighted images and introduced a constant real number for noise-suppressed MP2RAGE reconstruction. DGM structure [globus pallidus (GP), putamen, caudate and thalamus] volumes were normalized with the SIENAX normalization factor. Concurrent MP2RAGE T1-hypointensity and FLAIR T2-hyperintensity indicated DGM lesions. Brain white matter T2 lesion volume (T2LV) was expert-quantified. Unadjusted and age-adjusted group differences (two-sample t-tests and Spearman correlations) were assessed. Results: Total DGM volumes were lower in MS vs. controls (43.5 vs. 46.3 mL, p=0.034), varying by region and most pronounced in the caudate (9.0 vs. 9.9 mL, p=0.008). DGM volumes inversely correlated with EDSS (total DGM: r=−0.45, p=0.014; GP: r=−0.42, p=0.023; putamen: r=−0.44, p=0.016; caudate: r=−0.37, p=0.047) and T2LV (total DGM: r=−0.64, p Conclusions: We introduce an automated pre-processing method for 7T DGM volume segmentation, which shows a link between DGM atrophy and both white matter lesions and physical disability in RRMS. Furthermore, thalamic lesions are associated with thalamic atrophy. Disclosure: Dr. Zurawski has received personal compensation for consulting, serving on a scientific advisory board, speaking, or other activities with Adelphi Real World.Dr. Chu has nothing to disclose. Dr. Tie has nothing to disclose. Dr. Tauhid has nothing to disclose. Dr. Healy has received research support from Verily Life Sciences, Analysis Group, Genentech, Novartis, and EMD Serono.Dr. Weiner has received personal compensation for consulting, serving on a scientific advisory board, speaking, or other activities with Genentech, Tiziana Life Sciences, Tilos Therapeurics, IM Therapeutics, vTv Therapeutics, Biogen, Magnolia Therapeutics, and MedDay Pharmaceuticals. Dr. Weiner has received research support from NIH, NMSS, EMD Serono, Novartis, Sanofi Genzyme, Teva Neurosciences, and Verily Life Sciences.Dr. Bakshi has received personal compensation for consulting, serving on a scientific advisory board, speaking, or other activities with Bayer, Biogen, Celgene, EMD Serono, Genentech, and Novartis. Dr. Bakshi has received research support from EMD Serono and Sanofi-Genzyme.