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

PurposeTo measure the longitudinal change in multiple sclerosis (MS) lesion susceptibility using quantitative susceptibility mapping (QSM). Materials and MethodsThe 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. ResultsLesion susceptibility values relative to normal-appearing white matter (NAWM) changed from 3.616.11 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). ConclusionMS 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.