The Influence of Contrast-to-Noise Ratio on the Discrimination Between Cortical and Juxtacortical Lesions in Multiple Sclerosis.

The objective of this study was to investigate the contrast-to-noise ratio (CNR) between cortical gray matter (GM) and subcortical white matter (WM) across the cortex in relation to the ability of 3-dimensional fluid attenuated inversion recovery and 3-dimensional double inversion recovery to distinguish between cortical lesions (CLs) and juxtacortical lesions (JCs). A total of 38 multiple sclerosis patients underwent magnetic resonance imaging. Two neuroradiologists scored CLs and JCs on magnetic resonance imaging in 9 cerebral areas. Lesions were marked as nonclassifiable (NCs) when blurred WM-GM boundary leads to inaccuracy of their discrimination. The CNR between WM and GM (CNRWM-GM) was evaluated across the cortical areas. The CNRWM-GM varies across the cortex; the lower values were found in motor and sensorimotor areas where almost all NCs were localized. A strong negative correlation was found between CNRWM-GM and NCs. Discrimination between CLs and JCs is affected from the sharp visualization of the WM-GM boundary, which is directly related to CNRWM-GM.