Paramagnetic Rim Lesions are Highly Specific for Multiple Sclerosis in Real-World Data.

Area of Science:

• Neuroimaging
• Neurology
• Biomarker Discovery

Background:

• Paramagnetic rim lesions (PRL) are an emerging biomarker in multiple sclerosis (MS).
• PRL are associated with increased disease severity and may support MS diagnosis.

Purpose of the Study:

• To determine the specificity and sensitivity of PRL for differentiating MS from its mimics.
• To utilize real-world clinical and imaging data for diagnostic discrimination.

Main Methods:

• Retrospective analysis of a longitudinal cohort with prospectively collected data.
• MRI scans using a T2*-weighted sequence (SWAN protocol) were reviewed for PRL.
• PRL were categorized using modified consensus criteria (definite, probable, possible).

Main Results:

• A total of 580 patients were evaluated (473 MS, 57 NIND, 50 OIND).
• "Definite" or "probable" PRL achieved 98% specificity and 36% sensitivity in discriminating MS from NIND and OIND.
• Interrater agreement for identifying definite/probable PRL was nearly perfect.

Conclusions:

• PRL demonstrate high specificity for MS, aiding in diagnostic evaluation.
• Modest sensitivity restricts their use as standalone diagnostic indicators.
• Including "possible" PRL significantly reduces specificity, warranting cautious interpretation to avoid misdiagnosis.