Abstract Details

To investigate medulla oblongata (MO), pons and mesencephalon atrophy on brain 3D T1-weighted images in early stage patients with Multiple Sclerosis (MS) using a fully-automated deep learning-based segmentation approach.

Brainstem (BS) involvement is regarded as a bad prognostic sign and can limit life expectancy in MS. In contrast to cortical, subcortical and spinal cord atrophy, BS atrophy has not been systematically investigated in early stage MS.

A novel, fully-automated deep learning-based segmentation approach (Sander et al. 2019) was used to assess BS volumes from high-resolution 3D T1w MPRAGE images obtained at either a 3T Skyra (24.4%) or 1.5T Avanto Scanner (75.6%) (Siemens Healthineers) in 182 patients with early stage MS (mean age 37.7 years, SD 11.2, 61% women, median EDSS 1.75, IQR 1.5, median disease duration 1.4 years, range 0.01-3.98 years) and 80 age- and sex-matched healthy controls (HC; mean age 37.7 years, SD 13.3, 60% women) as part of the ongoing Swiss MS cohort-study. BS function was assessed using the Neurostatus-EDSS BS Functional System Score.

Compared to HC, patients showed significant MO volume reductions (p=0.004; % difference 4.96%) in absence of significant atrophy of the mesencephalon and pons. This difference was visible in patients with (p=0.001) and without (p=0.016) clinical BS involvement (adjusted for age and sex). Even the patients with the shortest disease duration below the 25^th percentile (range 0.01-0.72 years) showed a significant MO atrophy compared to HC (p=0.024, adjusted for age and sex).

Isolated MO atrophy occurs very early in MS in absence of significant pons and mesencephalon atrophy. This observation is independent of clinical BS involvement. Further longitudinal studies are necessary to investigate its role as a marker for disease course monitoring and outcome prediction.