NEW YORK (Reuters Health) – Patients with incidental MRI anomalies resembling demyelinated lesions that are not due to another disease process are at increased risk for multiple sclerosis (MS), researchers in San Francisco report in the December 10th online issue of Neurology.

“Some observed changes (on MRI) are highly suggestive of demyelinating pathology based both upon their location and morphology in the CNS (i.e., periventricular geography, involvement of the corpus callosum, ovoid, well-circumscribed, homogeneous),” Dr. Darin T. Okuda and co-authors note. They call such lesions in the absence of symptoms “radiologically isolated syndrome.”

The research team at the University of California, San Francisco Multiple Sclerosis Center studied the natural history of radiologically isolated syndrome in 44 patients ages 16 to 67 years. Thirty patients were followed clinically; longitudinal MRI data were available for 41 patients.

Except for one patient with a history of stroke and two with asymmetric reflexes, initial neurologic examinations were normal. However, cerebrospinal fluid profiles obtained from 27 subjects were suggestive of MS in 18 (67%).

During a median follow-up of 2.7 years (maximum 26 years), 24 of 41 patients (59%) exhibited radiologic progression.

Of 30 patients who were followed clinically, 10 (30%) converted to clinically isolated syndromes or clinically defined MS. Median time to the first clinical event was 5.4 years (maximum 9.8 years). No other disease entity has been identified in this cohort.

Dr. Okuda’s team cautions that “these data should not be generally applied in those cases with nonspecific brain MRI anomalies, leukoariosis, or those who fail to meet validated dissemination in space criteria.”

Noting that “MS remains a clinicopathologic entity and patients must have symptoms to receive a diagnosis,” authors of an accompanying editorial point out that some patients with demyelinating lesions remain permanently asymptomatic.

Drs. Dennis Bourdette and Jack Simon at the Oregon Health & Science University in Portland therefore advise that physicians “not tell patients with radiologically isolated syndrome that they have MS (or) treat them with disease-modifying therapies.”

Reference:
Neurology 2008.