A single, unified set of magnetic resonance imaging (MRI) criteria that can apply to relapsing remitting multiple sclerosis (MS) and primary progressive MS should be considered for future revisions to the McDonald diagnostic criteria, according to a poster presentation at the 37^th Congress of the European Committee for Treatment and Research in Multiple Sclerosis.

“Historical diagnostic criteria for multiple sclerosis (MS) requiring two clinical attacks disseminated in space and time are inappropriate for diagnosis of primary progressive MS (PPMS),” wrote Madiha Shatila, Queen Square MS Centre, Department of Neuroinflammation, UCL Institute of Neurology, London, UK, and co-authors.

Researchers aimed to compare the McDonald 2017 relapsing remitting MS dissemination in space and dissemination in time criteria to the McDonald 2017 primary progressive MS dissemination in space and dissemination in time criteria in patients with suspected primary progressive MS.

A total of 117 patients with possible primary progressive MS were evaluated between the years 2016-2020, with 97 patients ending up with a primary progressive MS diagnosis. All participants had MRI of the brain and spinal cord as well as cerebrospinal fluid examination.

Researchers retrospectively applied the McDonald 2017 criteria for primary progressive MS and the McDonald 2017 criteria for relapsing remitting MS, alone and in combination, for diagnosis of primary progressive MS.

Results from McDonald 2017 primary progressive MS  and McDonald 2017 relapsing remitting MS dissemination in space criteria demonstrated high accuracy and sensitivity, however, the McDonald 2017 relapsing remitting MS dissemination in space criteria showed lower specificity.

Results from McDonald 2017 primary progressive MS and the relapsing remitting MS dissemination in time criteria both showed high sensitivity and accuracy, but the McDonald primary progressive MS dissemination in time showed less specificity.

Overall, diagnostic criteria between the McDonald 2017 relapsing remitting MS criteria and the McDonald 2017 primary progressive MS criteria showed very similar abilities to diagnose MS.

Researchers suggested complexity in diagnosing MS could be resolved by unifying the criteria.

“Future revisions to the McDonald criteria should consider a single, unified set of MRI criteria that could be applied to both relapsing and progressive MS,” Shatila et al concluded.

Shatila, M, Brownlee W, et al. Do we need separate MRI diagnostic criteria for primary progressive multiple sclerosis? Presented at the 37^th Congress of the European Committee for Treatment and Research in Multiple Sclerosis. October 13-15; Virtual.