Synthetic MRI in Progressive MS: Associations with Disability.

Area of Science:

• Neuroimaging
• Quantitative MRI
• Multiple Sclerosis Research

Background:

• Synthetic MRI (SyMRI) offers rapid, multi-contrast imaging from a single acquisition.
• SyMRI is utilized as an alternative to conventional MRI for lesion detection and volumetric analysis in multiple sclerosis (MS).
• Previous studies have established SyMRI's role in relapsing-remitting MS, but its utility in progressive MS requires further investigation.

Purpose of the Study:

• To identify a Synthetic MRI (SyMRI) variable that correlates with severe disability (Expanded Disability Status Scale [EDSS] ≥ 6) in patients with progressive multiple sclerosis (MS).
• To explore the relationship between quantitative MRI metrics and clinical disability in progressive MS.
• To assess the potential of SyMRI for monitoring disease progression and disability in MS.

Main Methods:

• Twenty-four patients with progressive MS underwent SyMRI using a 2D axial QRAPMASTER sequence.
• Analysis included volumetric parameters, global myelin fraction (MyCF), and quantitative values from various tissue masks (normal-appearing white/gray matter, lesion, corpus callosum).
• Statistical analysis involved t-tests to compare groups (EDSS < 6 vs. ≥ 6) and univariate binary logistic regression to identify predictors of disability.

Main Results:

• Significant differences between EDSS groups were observed in brain parenchymal fraction, white matter fraction, MyCF, and corpus callosum volume (P ≤ .05).
• Global myelin fraction (MyCF) emerged as the best predictor of EDSS category, with higher MyCF associated with lower disability (P = .08, OR = 0.59).
• These findings suggest a link between myelin integrity and clinical disability in progressive MS.

Conclusions:

• Synthetic MRI (SyMRI) can differentiate volumetric parameters based on EDSS in progressive MS using a single acquisition.
• Higher myelin fraction (MyCF) values derived from SyMRI are associated with lower patient disability.
• SyMRI and myelin quantification show promise as valuable tools for clinical practice in managing progressive MS.