For anyone living with or at risk of multiple sclerosis, the precision of the initial diagnostic scan can determine how quickly treatment begins — and whether a misdiagnosis sets someone on the wrong therapeutic path for years. A newly updated French national framework for MS neuroimaging encodes two lesion-level biomarkers that were only formally incorporated into diagnostic criteria in 2024, potentially shortening the diagnostic odyssey for a disease that still takes an average of several years to confirm.
The revised OFSEP protocol, developed through a modified Delphi consensus by a multidisciplinary neuroradiology and neurology working group, mandates isotropic fat-suppressed 3D FLAIR imaging at 1 mm³ resolution alongside a dedicated 3D susceptibility-sensitive sequence — either T2* GRE or susceptibility-weighted imaging with filtered phase — to detect the central vein sign (CVS) and paramagnetic rim lesions (PRLs). CVS exploits the perivenous anatomy of MS white-matter lesions to distinguish them from mimics like small-vessel ischemic disease, while PRLs reflect the chronic iron-laden microglial rim that marks smoldering, slowly expanding lesions with worse long-term outcomes. Notably, the optic nerve is now recognized as a fifth topographical domain, driving inclusion of a dedicated orbital protocol at initial diagnosis. Gadolinium use is restricted to targeted indications on follow-up scans, reducing cumulative contrast exposure.
This framework matters beyond French borders because it demonstrates that CVS and PRL detection, previously considered research-grade imaging, can be standardized across routine 1.5 T and 3 T scanners without specialized hardware. The broader MS imaging community has grappled for years with how to operationalize these biomarkers at scale; this vendor-neutral consensus offers a replicable template. The key limitation is that it remains a consensus document, not a prospective validation trial — real-world sensitivity and specificity data across diverse scanner platforms are still needed. Still, the move to formalize gadolinium restriction reflects accumulating evidence on brain deposition concerns, making this a patient-safety advance as well as a diagnostic one.