Abstract
Objective/Background : Multiple sclerosis (MS) shows a gradient of periventricular white matter damage, especially close to the ventricles. Although evaluating this gradient has demonstrated its usefulness in understanding microstructural changes in MS, assessments have primarily used nonspecific imaging techniques, such as two-dimensional magnetization transfer ratio and T1 maps. This study examined the periventricular gradient of myelin content using myelin volume fraction (MVF) maps, axion volume fraction (AVF) maps, and g-ratio in healthy controls, relapsing-remitting MS (RRMS), secondary progressive MS (SPMS), myelin oligodendrocyte glycoprotein antibody-associated disease (MOGAD), and neuromyelitis optica spectrum disorders (NMOSD).
Methods : Synthetic magnetic resonance imaging (MRI) and 2-shell DWI on a 3-T scanner were performed in 23 healthy controls and 88 RRMS, 18 SPMS, 30 MOGAD, and 23 NMOSD participants. MVF, AVF, and g-ratio data were obtained from lesions identified using fluid-attenuated inversion recovery on synthetic MRI. The normal-appearing white matter bands extending from the ventricle to the cortex were evaluated, and the first 10 bands were analyzed. Periventricular gradients of the MVF, AVF, and g-ratio were compared among the groups using the Kruskal-Wallis test. Correlations between periventricular gradient and expanded disability status scale (EDSS) or disease duration (DD) were assessed using Spearman’s correlation coefficients.
Results : The periventricular gradient of MVF was significantly higher in the RRMS and SPMS groups than that in healthy controls (p＝0.042 and p＜0.001, respectively) and significantly higher in the SPMS group than that in the RRMS group (p＝0.011). No significant differences were observed between healthy controls and patients with MOGAD or NMOSD or between the groups regarding AVF and g-ratio. In RRMS and SPMS combined, the periventricular gradient of MVF was significantly correlated with EDSS and DD.
Conclusion : Demyelination in MS was more prominent close to the ventricles, with a gradient correlating with clinical severity, possibly aiding in differentiating MS from MOGAD and NMOSD.
