Improved MRI quantification of spinal cord atrophy in multiple sclerosis

Abstract

PSIR/ASM proved more reproducible than established methods of evaluating CSA in MS and also provides the lowest number of subjects per arm for 6-month and 1-year clinical trials.

Clinically Feasible Microstructural MRI to Quantify Cervical Spinal Cord Tissue Injury Using DTI, MT, and T2*-Weighted Imaging: Assessment of Normative Data and Reliability

“…Image acquisition was successful in all subjects, and automated analysis provided robust readouts from multiple ROIs, with the results validated by acceptable reliability data. Our results establish normative data for CSA, FA, and MTR that are consistent with previous reports at 3T, 12,21,[27][28][29] in addition to our novel T2*WI WM/GM metric. T2*WI WM/GM, FA, and MTR all showed strong graywhite contrast and differences between individual WM tracts.…”

“…Reliability of the CSA measurement was not assessed due to time constraints, but it likely surpasses that of our other measures because it has been previously reported to have TRCOV under 0.5% by using similar techniques. 12 Reliability was greatest in the rostral region for all techniques, where healthy subjects and patients with DCM showed similar results. In contrast, patients with DCM showed trends toward diminished reliability at MCLs and caudal levels, likely related to distorted anatomy, increased partial volume effects, increased susceptibility artifacts, and less accurate registration to the SCT template.…”

“…[1][2][3] These provide measures of axonal integrity and myelin quantity that correlate with functional impairment in conditions such as degenerative cervical myelopathy (DCM) [5][6][7]9 and MS, 3,9 albeit with limited physiologic specificity (eg, fractional anisotropy [FA] reflects both demyelination and axonal injury). 10,11 SC crosssectional area (CSA) computed from high-resolution anatomic images can measure atrophy (eg, in MS) 12 or the degree of SC compression in DCM.…”

A Novel MRI Biomarker of Spinal Cord White Matter Injury: T2*-Weighted White Matter to Gray Matter Signal Intensity Ratio

“…Cord compression causes ischemia that often represents partially reversible neurologic impairment, 30 whereas atrophy of the SC (rostral or caudal compression) suggests axonal loss or demyelination, which is more likely to be permanent. 12 MCL CSA has been previously demonstrated to correlate well with severity in DCM, 31 and atrophy measurement has also proved useful in DCM 12 and MS. [4][5][6] However, MCL CSA does not account for motion-related dynamic injury, which is also believed to be an important mechanism of tissue injury in DCM, 31 suggesting that this metric may be better used in conjunction with other measures that directly interrogate microstructural changes. FA showed strong group differences and moderate correlations with impairment, but diagnostic accuracy was modest.…”

“…3 The strongest results include cross-sectional area (CSA) as a measure of spinal cord atrophy, the DTI metric fractional anisotropy (FA) to evaluate axonal integrity, and the magnetization transfer ratio (MTR) as a measure of demyelination. 3 Spinal cord CSA has shown moderate-to-strong correlation with disability in MS [4][5][6] but is a nonspecific measure of tissue injury and shows high intersubject variability in healthy subjects, 7,8 somewhat limiting its utility. FA has demonstrated moderate correlation with global and focal disability in dozens of studies involving various pathologies 3,[9][10][11][12][13][14] but has yet to achieve clinical uptake due to a lack of standardized/portable acquisition methods and cumbersome analysis techniques.…”