A recent large scale multicenter study reported a poor correlation between EDSS and normalized brain volume (r=−0.18), cross section area (r=−0.26), MT ratio (MTR) of whole brain tissue (r=−0.16) and MTR of gray matter (GM) (r=−0.17), and no significant correlation between other MR metrics and patients EDSS scores ( 13). Contrast-enhanced lesions are only moderately correlated with disability in the first six months, and are not predictive of changes in the EDSS in the subsequent 12 or 24 months ( 12). However, conventional clinical MRI only correlates modestly with disability assessed by the expanded disability status scale (EDSS) ( 6), also T 2-hyperintense lesion load in MS is poorly correlated with disability (r=0.2–0.5) in cross-sectional studies ( 7- 11). Clinical T 1- and T 2-weighted fast spin echo (FSE) imaging ( 2), gadolinium enhancement ( 3), diffusion tensor imaging (DTI) ( 4), and Magnetization Transfer (MT) ( 5), all show high sensitivity for abnormalities in patients with MS. Conventional clinical MRI sequences are very sensitive to the presence of white matter disease including MS. Magnetic resonance imaging (MRI) is the current gold standard imaging modality for diagnosis of disease of the brain ( 2- 10). Loss of myelin is the hallmark of numerous inflammatory and neurodegenerative disorders, including multiple sclerosis (MS) and other demyelinating diseases such as optic neuritis, neuromyelitis optica, transverse myelitis, and acute disseminated encephalomyelitis ( 1). It helps increase nerve conduction velocity. It is present in the form of a sheath surrounding the axons of some neurons, and insulates axons from electrically charged ions and molecules. Myelin is a major component of the CNS and PNS, and accounts for about 14% of the wet mass and 50% of the dry mass of the white matter of the brain ( 1). It is formed by two different types of support cells, oligodendrocytes in the central nervous system (CNS) and Schwann cells in the peripheral nervous system (PNS). Myelin is a concentrically laminated membranous structure consisting of alternating protein and lipid layers, and contains approximately 20% protein and 80% lipid ( 1). The article did not undergo external peer review. Email: and Peer Review: This article was commissioned by the editorial office, Quantitative Imaging in Medicine and Surgery. Department of Radiology, University of California San Diego, La Jolla, CA 92037, USA.
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