Assessing the cervical canal area in multiple sclerosis with spinal cord sagittal 2D T2-weighted sequences

Objective: We explored the feasibility of our pipeline to make semi-automated estimations of the cervical canal area (CCaA), a proxy for spinal cord reserve in multiple sclerosis (MS), using conventional MRI sequences other than 3D T1-weighted images (T1WI), with which the pipeline was initially validated.

Materials and methods: Fifty-three patients with MS underwent sagittal brain 3DT1WI and cervical 2DT1WI, T2WI, and short tau inversion recovery (STIR). Semi-automated CCaA estimations were obtained from reconstructed axial images at the C2/C3 and C3/C4 levels. Agreement with manual segmentations was evaluated using the Dice coefficient (DC). Intraclass correlation coefficients (ICC) assessed consistency across sequences, and Spearman correlation tested associations with Expanded Disability Status Scale (EDSS).

Results: After quality control, the final cohort comprised 36 patients with MS at the C2/C3 level and 43 at C3/C4. CCaA estimation failed on 2DT1WI. Agreement with manual masks was stronger for T2WI (DC = 0.92 [0.89-0.93]) and STIR (DC = 0.90 [0.88-0.92]). The equivalence of CCaA across sequences was higher at C3/C4 than at C2/C3: ICC T2WI-3DT1WI was 0.67 (0.38-0.82) and 0.63 (0.26-0.82), while ICC STIR-3DT1WI was 0.80 (0.64-0.89) and 0.52 (0.22-0.70), respectively. At C3/C4, T2WI CCaA and EDSS were significantly correlated (rho -0.34, p 0.023).

Discussion: CCaA can be reliably estimated from 2DT2WI and STIR images. T2WI-derived CCaA was significantly associated with disability.