Paramagnetic Rim Lesions in Multiple Sclerosis

Paramagnetic rim lesions (PRLs) have been associated with multiple sclerosis (MS) disability and progression (NEJM JW Neurol Aug 24 2023 and Ann Neurol 2020; 88:1034). In this study, investigators used 7T and 3T MRI to evaluate the evolution of contrast-enhancing lesions (CELs) into PRLs in 23 patients with MS.

Out of 93 CELs, 37 developed into PRLs at 6-month follow-up MRI. These lesions had lower T1 intensity and larger volume on the initial MRI. All lesions that became PRLs had paramagnetic signal on the initial or 3-month 7T MRI, whereas 25 of 43 of non-PRLs were isointense to normal-appearing white matter on the initial 7T MRI, and 4 of the non-PRLs had an initially hypointense rim.