Microstructural Modulations in the Hippocampus Allow to Characterizing Relapsing-Remitting Versus Primary Progressive Multiple Sclerosis

摘要

Whether gray matter (GM) regions are differentially vulnerable in Relapsing-Remitting and Primary Progressive Multiple Sclerosis (RRMS and PPMS) is still unknown. The objective of this study was to evaluate morphometric and microstructural properties based on structural and diffusion magnetic resonance imaging (dMRI) data in these MS phenotypes, and verify if selective intra-pathological alterations characterise GM structures- Diffusion Tensor Imaging (DTI) and 3D Simple Harmonics Oscillator based Reconstruction and Estimation (3D-SHORE) models were used to fit the dMRI signals, and several features were subsequently extracted from the regional values distributions (e.g., mean, median, skewness). Statistical analyses were conducted to test for group differences and possible correlations with physical disability scores. Results highlighted 3D-SHORE sensitivity to microstructural differences in hippocampus, which was also significantly correlated to physical disability. Conversely, morphometric measurements did not reach any statistical significance. Our study emphasized the potential of dMRI, and in particular the importance of advanced models such as 3D-SHORE with respect to DTI in characterizing the two MS types. In addition, hippocampus has been revealed as particularly relevant in the distinction of RRMS from PPMS and calls for further investigation.