Proceedings of the 25th BCTRIMS Annual Meeting

Introduction: MRI is the most important paraclinical tool to support the diagnosis of multiple sclerosis (MS) and identify disease mimics. Applying current diagnostic criteria (McDonald 2017) increases the number of cases diagnosed but has demonstrated a reduction in specificity. People with MS also have risk factors for cerebral vessel vascular disease (CSVD), compromising correct allocation of new lesions to their cause, and such uncertainty may directly impact on treatment decisions. The inclusion of signals from conventional MRI sequences, such as the “central vein signal (CVS)” and the “paramagnetic rim lesion (PRL)” extracted from magnetic susceptibility (SWI) sequences, can contribute to increased specificity.

Objectives: To explore the potential of the magnetic susceptibility sequence to distinguish between lesions caused by multiple sclerosis (MS) from disease mimics, particularly cerebral small vessel disease (CSVD), in a clinical setting, according to the current McDonald 2017 imaging criteria.

Methods: Retrospective analysis reviewed 3T brain MRI scans of patients (n=668) of outpatients during the period between January 2016 and December 2020 with white matter focal lesions, being MS (n = 63) and CSVD (n = 606). White matter lesions (WMLs), detected using fluid-attenuated inversion recovery (FLAIR), susceptibility, phase-sensitive and T1 weighted imagens were analysed by two experienced neuroradiologists, identifying and characterizing WMLs, including the presence of the CVS and PRL.

Results: The identification of ⩾1 PRL was the optimal cut-off and had high specificity (99.9%, confidence interval (CI) = 98.20%–99.99%) when distinguishing MS from CSVD. All patients with a PRL showing a central vein sign (CVS) in the same lesion (n = 48) had MS, giving a specificity of 100% (CI = 98.8%–100.0%).

Conclusion: The integration of imaging findings based on pathophysiology in the diagnostic criteria of Mc Donald 2017 for imaging reduce errors of diagnostic interpretation in MS.