Revised McDonald criteria allow for diagnosis of multiple sclerosis in atypical cases

Key takeaways:

• A total of 32% of patients with radiological-only onset and 17% with atypical onset met the new criteria.
• “Select 6” central vein sign is one of the most useful tools to confirm MS diagnosis in atypical cases.

WEST PALM BEACH, Fla. — Revisions made in 2024 to the McDonald criteria allowed for the diagnosis of multiple sclerosis in a small cohort of individuals with atypical presentation, according to a speaker at ACTRIMS.

“The central vein sign has emerged as an important biomarker in the diagnostic evaluation of MS,” Alexandra Scharf, MS, a third-year doctoral student at Case Western Reserve University, said in her presentation. “The ‘Select 6 criteria,’ which is based on the radiological definition of a central vein, requires evidence of six or more white matter lesions and the central vein sign.”

Proposed revisions to the McDonald criteria made in 2024 allow for the diagnosis of MS in people with radiologically isolated syndrome (RIS) where MRI evidence exists of dissemination in time (DIT) and space (DIS), or if DIS is confirmed via imaging along with Select 6 central vein sign (CVS) criteria.

As such, the researchers sought to apply the updated proposal plus CVS indications to individuals with atypical and radiological-only presentations enrolled in the 24-month CAVS-MS study.

Their cross-sectional analysis included baseline data from 420 enrollees, for whom symptom onset at baseline was defined as either typical, atypical, radiological only or progressive.

Additionally at baseline, DIT and DIS were determined via MRI, while CVS was quantified on fluid attenuated inversion recovery, with CSF analysis for oligoclonal bands (OCB) also acquired.

Scharf and colleagues subsequently analyzed enrollees with radiological-only presentation and atypical symptom onset who fulfilled DIT, DIS and Select-6 CVS, OCB, as well as those fulfilling McDonald 2024 criteria.

According to the results, 19% of CAVS-MS enrollees overall met the 2024 McDonald criteria, 32% of those with radiological-only onset and 17% of those with otherwise atypical onset.

Data further showed that 166 individuals had an atypical onset, with 25 others were deemed as having radiological-only presentation. From this combined 191-person subset, 44 (23%) fulfilled DIS only, eight (4%) fulfilled DIT only, and seven (4%) met both DIT and DIS criteria — all of whom met the proposed McDonald criteria.

The researchers additionally reported that of the 44 participants meeting DIS only criteria, 19 were Select 6 positive, 15 had OCB, and five others were Select 6 positive and had OCB. Only 29 individuals passed muster when the McDonald criteria were applied.

“Central vein sign is among the most useful paraclinical tools to confirm a diagnosis of MS in individuals with atypical onset or radiological-only presentation,” Scharf said. “Further study and long term follow-up is required to validate diagnostic accuracy in this patient population.”