PD15-05 DIFFUSION TENSOR IMAGING REVEALS CEREBELLAR WHITE MATTER TRACT DISRUPTIONS ASSOCIATED WITH VOIDING DYSFUNCTION IN WOMEN WITH MULTIPLE SCLEROSIS

INTRODUCTION AND OBJECTIVE:
The cerebellum has emerged as a brain center integrally involved in regulating micturition. Alterations seen in cerebellar functional connectivity (FC) in women with multiple sclerosis (MS) and voiding dysfunction (VD) suggest the need for further characterization. This study builds on these findings by using diffusion tensor imaging (DTI) to assess white matter (WM) tracts in the cerebellum of women with MS and VD. By analyzing WM structural connectivity, we identify specific tract disruptions in this population.

METHODS:
Eleven women with clinically stable MS and voiding dysfunction (VD) (defined as % post void residual/bladder capacity≥40%, Liverpool Nomogram percentile<10%, or performing self-catheterization) were recruited. DTI scans were performed on a 7T MRI, with images processed using tract-based spatial statistics (TBSS) and analyzed using MRtix3 to quantify fractional anisotropy (FA), mean diffusivity (MD), axial diffusivity (AD), and radial diffusivity (RD) in key WMTs. Specifically, the cerebellar peduncles and associated WM pathways were analyzed, based on prior neurogenic lower urinary tract dysfunction studies, in comparison to ten healthy women.

RESULTS:
Compared to controls, patients with MS and VD exhibited significant reductions in FA and elevations in MD and RD in the superior and middle cerebellar peduncles, with alterations most pronounced in connections between the cerebellum and brainstem. These observations suggest loss of fiber orientation and tissue integrity, most likely due to MS demyelination or other structural alterations, however these lesions not found in the cerebellum (Figure 1). Additionally, these specific tracts are critical for sensorimotor integration and autonomic regulation, providing a structural basis for observed functional changes.

CONCLUSIONS:
This study provides evidence of disrupted cerebellar WM integrity in women with MS and voiding dysfunction, highlighting a structural basis for observed cerebellar FC alterations. Our findings suggest that the superior and middle peduncles may play a role in neurogenic lower urinary tract dysfunction in MS. These results underscore the potential of DTI for identifying WM changes associated with voiding dysfunction in MS, offering insights that may inform therapies for managing urinary symptoms in this population.