A pilot MRI study of white and grey matter involvement by multiple sclerosis spinal cord lesions

Objectives: Spinal cord pathology is a major cause of disability in multiple sclerosis (MS) and pathology studies show multifocal demyelinating lesions in white matter (WM) tracts and central grey matter (GM). Better localisation of cord lesions by in vivo MRI may help to understand the structural-functional effects of spinal cord pathology in MS.

Methods: Three-Tesla MRI was performed on upper cervical cord in 15 MS patients and one clinically isolated syndrome. Axial 3D gradient-echo fast field echo (3D-FFE) and phase sensitive inversion recovery sequences (3D-PSIR) were acquired. Two readers reviewed images to detect and classify lesions: WM-only, mixed WM-GM or GM-only. Location of the WM component was classified: anterior (AC), lateral (LC) or posterior (PC) column.

Results: Fifty one lesions were identified: 32 (63%) mixed WM-GM, 19 (37%) WM-only, no GM-only. Most were in LC (n=30, 59%), followed by PC (n=18, 35%) and AC (n=3, 6%). Mean lesion areas: AC 4.3mm(2), LC 8.5mm(2), PC 11.3mm(2), corresponding to 6.1%, 12% and 16.1% of mean cord area, respectively. Mean lesion lengths: 18.3mm in AC, LC 17.6mm and PC 24.8mm.

Conclusions: While there was good depiction of WM tract involvement by cord lesions, involvement of central grey matter was not as clear. Noting the important effects of spinal cord pathology in MS, further work to better depict cord lesions by in vivo imaging is warranted.