Longitudinal change in magnetic susceptibility of new enhanced multiple sclerosis (MS) lesions measured on serial quantitative susceptibility mapping (QSM).

PURPOSE: To measure the longitudinal change in multiple sclerosis (MS) lesion susceptibility using quantitative susceptibility mapping (QSM).

MATERIALS AND METHODS: The study was approved by our Institutional Review Board. Longitudinal changes in quantitative susceptibility values of new enhanced-with-Gd MS lesions were measured at baseline magnetic resonance imaging (MRI) and on a follow-up MRI in 29 patients within 2 years using a 3D multiple echo gradient echo sequence on a 3T scanner. Paired t-test and the generalized estimating equations (GEE) model was used to analyze the longitudinal change.

RESULTS: Lesion susceptibility values relative to normal-appearing white matter (NAWM) changed from 3.61 ± 6.11 ppb when enhanced-with-Gd at the baseline MRI to 20.42 ± 10.23 ppb when not-enhanced-with-Gd at the follow-up MRI (P < 0.001).

CONCLUSION: MS lesion susceptibility value increases significantly as the lesion evolves from enhanced-with-Gd to not-enhanced-with-Gd, serving as a disease biomarker. J. Magn. Reson. Imaging 2016;44:426-432.