Assessing the central vein sign in multiple sclerosis using contrast-enhanced isotropic FLAIR* on a 1.5T system: a prospective observational study

Abstract

Central vein sign (CVS) in isotropic FLAIR* imaging is a successful marker for multiple sclerosis (MS). Our objective is to explore the prevalence of gadolinium-based contrast agent (GBCA) enhanced FLAIR* in a 1.5 T system for CVS assessment. Materials and Methods: This prospective observational study, conducted from February 2022 to February 2023, involved 41 participants with MS using 1.5T and 28 participants using 3T GBCA-enhanced FLAIR*. First, the eligibility of each demyelinating lesion was determined based on the NAIMS-CVS criteria. Then the CVS-eligible lesions were classified as CVS+ or CVS- by the central rater and co-rater (A.P.). CVS+ prevalence was assessed using the Select-n* and percentage-based methods. Results: Out of 895 CVS-eligible lesions, 341 (59.7 %) were CVS+ in the 1.5T group, and 226 (69.7 %) were CVS+ in the 3T group. Thirty-eight (93 %) cases in 1.5T and 25 (89 %) cases in 3T were select-3*(+), while 39 (95 %) cases in 1.5T and 27 (96 %) cases in 3T were select-6*(+), (p > 0.05). Inter and intra-rater reliability for the 1.5T system was substantial (ICC1: 0.79 and ICC2: 0.78). GBCA-enhanced FLAIR* revealed a mean CVS+ of 63 % +/- 14.8 in the 1.5T and 72 % +/- 13.4 in the 3T group on percentage-based analysis (p = 0.015). Conclusion: GBCA-enhanced FLAIR* in 1.5T systems demonstrated favorable performance in CVS evaluation, despite being less effective compared to the CVS outcomes of GBCA-enhanced FLAIR* at 3T magnetic field strength. This initial finding is significant given the widespread global use of 1.5T systems.