Quantitative susceptibility mapping for differentiating multiple sclerosis from cerebral small vessel disease

Abstract

Background and Purpose: With the increasing prevalence of cerebrovascular risk factors in young adults, accurate differentiation of multiple sclerosis (MS) from cerebral small vessel disease (SVD) remains challenging because of the significant overlap in the appearance of white matter lesions on conventional magnetic resonance (MR) images. The purpose of this study was to use quantitative susceptibility mapping (QSM) to differentiate patients with MS from patients with SVD. Materials and Methods: Thirty-two patients with relapsing-remitting MS and 40 patients with SVD were selected in this institution review board-approved retrospective study. All patient examinations included QSM and T2-weighted FLAIR (T2w). All T2w hyperintense lesions were analyzed on QSM for susceptibility relative to normal-appearing white matter and were evaluated for the presence of hyperintense rims and the central vein sign. Receiver operating characteristic (ROC) curve analysis was performed to assess the diagnostic accuracy of differentiating MS patients from SVD patients. Results: The mean susceptibility value of SVD lesions was significantly lower than MS lesions (2.31 ± 9.68 ppb vs. 27.77 ± 20.27 ppb, p < 0.001). Of MS patients and MS lesions, 68.8% and 22.2% had hyperintense rims on QSM, respectively. Of MS patients and MS lesions, 75% and 37.6% had a central vein sign on QSM, respectively. Lesion susceptibility values allowed accurate differentiation MS from SVD with an area under the ROC curve (AUC) = 0.848 for lesion differentiation, AUC = 0.999 for patient differentiation, and an optimal cut-off susceptibility value of 14.88 ppb. Conclusions: Magnetic susceptibility measured using QSM allows accurate differentiation of MS patients from SVD patients.