Abstract Details

Increased CPV has been reported in multiple sclerosis (MS) and has been suggested to reflect CP inflammation. The association between CPV and neurodegeneration remains relatively poorly understood. 

To assess the relationship between CPV and tissue-specific volumetric measures in the brain.

179 MS patients and 59 healthy controls (HCs), group matched for age and sex, were imaged on a 3T MRI scanner with an imaging protocol that included a 3D T1-weighted scan and T2-weighted FLAIR. T2 lesion volume (T2-LV) was measured. For each individual, SIENAX was run on a lesion inpainted image to obtain total volumes of brain (BV), grey matter (GMV), white matter (WMV), and ventricular volume (VV). CPV was automatically calculated from the same image using a Gaussian Mixture Models-based approach. CPV was normalized by the SIENAX scaling factor. Group comparisons and correlations were adjusted for age and sex. A univariate general linear model was constructed to predict CPV from VV, while assessing the interaction effect between group and VV.

MS patients presented with significantly larger CP fractions when compared to HCs (2847 ± 967 vs. 2399 ± 876 mL, p=0.010). Age was significantly positively correlated with CP fraction (p ≤ 0.005) in both groups. Significant correlations were observed in MS patients between CP and GMV (r=-0.365), WMV (r=-0.188), BV  (r=-0.365) ,VV (r=0.691), and T2-LV (r=0.293) (all p ≤ 0.012). In the HC group, CP fraction was only associated with VV (r=0.806, p < 0.001). A significant group x VV interaction effect (p < 0.001) was identified when predicting CPV.

Unlike in HCs, CPV in MS patients relates to regional tissue volumes and T2-LV. CP enlargement is not fully explained by increased VV, potentially suggesting a link between CP inflammation and neurodegeneration.