Correlation of Apparent Diffusion Coefficient to cognitive impairment in Relapsing remittent multiple sclerosis (plaque, peri-plaque and Normal appearing white matter)

The purpose of this study was to determine diffusion coefficient (ADC) in plaque, peri-plaque and normal-appearing white matter (NAWM) in multiple sclerosis (MS), compare them with the control and correlate findings with cognitive state.Subjects and methodsSixty-five participants were included and categorized into MS patients with normal cognition (n=25); MS with mild cognitive impairment (n=20) and control group (no MS and normal cognition; n=20). The Montreal Cognitive Assessment was used to determine cognitive state. Mean ADC was measured in plaque, peri-plaques and NAWM, compared with ADC from corresponding white matter in control and correlated with cognitive scores. Chi Square and Pearson correlation coefficient were used.ResultsThe mean ADC of peri-plaque and NAWM in MS group with cognitive impairment was significantly higher than MS group with normal cognition (p<0.001) and control group (p<0.05) respectively. In MS patients with impaired cognition, the mean ADC in peri-plaque and NAWM demonstrated inverse correlations with cognitive state (r=−0.64, p<0.001) and (r=−0.56, p=0.01) respectively.ConclusionsADC values in peri-plaque and NAWM have an inverse correlation with cognition in MS. The ADC is useful for detecting subtle abnormalities in white matter and can be used as a predictor of cognitive state