WASHINGTON (FRONTLINE MEDICAL NEWS) – MRI can help to differentiate between neurosarcoidosis and primary angiitis of the central nervous system, according to a single-center study comparing the two conditions.

Patients with neurosarcoidosis were significantly more likely to display spinal cord, basal meningeal, and cranial nerve involvements than were patients with primary angiitis of the central nervous system (PACNS), making MRI an efficient tool in distinguishing between the two.

“This will help us to make a differential diagnosis more accurately,” Didem Saygin, MD, of the Cleveland Clinic, explained at the annual meeting of the American College of Rheumatology. “Because we can differentiate these two conditions just with MRI, this means we can better approach the patients and give the appropriate treatments early.”

Dr. Saygin and her coinvestigators at the Cleveland Clinic recruited 34 patients with PACNS and 42 patients with neurosarcoidosis, all of whom had brain and/or spinal cord MRIs performed close to the time of presentation. The average age was 45.6 years in the PACNS group and 44.1 years in the neurosarcoidosis group. The MRIs were blindly reviewed by two neuroradiologists who examined and recorded data on pachymeninges, leptomeninges, basal meninges, cranial nerves, cerebral gray and white matter, and the spinal cord itself. The sites, presence, patterns, localization, and lateral involvement for these were noted, as well as any mass effect, parenchymal hemorrhaging, and ventriculomegaly.

Unilateral cranial nerve involvement appeared on MRI in 71% of neurosarcoidosis patients, compared with 3.0% for PACNS. Neurosarcoidosis patients also had consistently higher rates of involvement of the spinal cord (cervical, 62.5% vs. 0%; thoracic, 45.8% vs. 0%) as well as basal meninges (basal cistern, 21.6% vs. 0%; brain stem, 27.0% vs. 3.0%).

However, there was no significant difference between PACNS and neurosarcoidosis patients in terms of the pachymeningeal and leptomeningeal involvement, pituitary/sella turcica involvement, and mass effect, the latter of which was seen in 20% of PACNS patients and 14% of those with neurosarcoidosis.

The relatively small sample size of 76 patients is a limitation of the study, Dr. Saygin said.

No funding source was disclosed for this study. Dr. Saygin did not report any relevant financial disclosures.