7T quantitative magnetization transfer (qMT) of cortical gray matter in multiple sclerosis correlates with cognitive impairment.

McKeithan LJ, Lyttle BD, Box BA, O'Grady KP, Dortch RD, Conrad BN, Thompson LM, Rogers BP, Newhouse P, Pawate S, Bagnato F, Smith SA
Neuroimage. 2019 203: 116190

PMID: 31525497 · PMCID: PMC7549401 · DOI:10.1016/j.neuroimage.2019.116190

Cognitive impairment (CI) is a major manifestation of multiple sclerosis (MS) and is responsible for extensively hindering patient quality of life. Cortical gray matter (cGM) damage is a significant contributor to CI, but is poorly characterized by conventional MRI let alone with quantitative MRI, such as quantitative magnetization transfer (qMT). Here we employed high-resolution qMT at 7T via the selective inversion recovery (SIR) method, which provides tissue-specific indices of tissue macromolecular content, such as the pool size ratio (PSR) and the rate of MT exchange (kmf). These indices could represent expected demyelination that occurs in the presence of gray matter damage. We utilized selective inversion recovery (SIR) qMT which provides a low SAR estimate of macromolecular-bulk water interactions using a tailored, B1 and B0 robust inversion recovery (IR) sequence acquired at multiple inversion times (TI) at 7T and fit to a two-pool model of magnetization exchange. Using this sequence, we evaluated qMT indices across relapsing-remitting multiple sclerosis patients (N = 19) and healthy volunteers (N = 37) and derived related associations with neuropsychological measures of cognitive impairment. We found a significant reduction in k in cGM of MS patients (15.5%, p = 0.002), unique association with EDSS (ρ = -0.922, p = 0.0001), and strong correlation with cognitive performance (ρ = -0.602, p = 0.0082). Together these findings indicate that the rate of MT exchange (k) may be a significant biomarker of cGM damage relating to CI in MS.

Copyright © 2019 Elsevier Inc. All rights reserved.

MeSH Terms (12)

Adult Cerebral Cortex Cognitive Dysfunction Female Gray Matter Humans Image Processing, Computer-Assisted Magnetic Resonance Imaging Male Middle Aged Multiple Sclerosis Young Adult

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