MR of sarcoidosis in the head and spine: spectrum of manifestations and radiographic response to steroid therapy.

PURPOSE To evaluate the role of MR in the diagnosis and treatment of patients with neurosarcoidosis.

METHODS The MR studies of 24 patients who satisfied stringent criteria for the diagnosis of sarcoid were retrospectively reviewed. All patients had signs and symptoms referable to the head and/or spine. The majority, 17 patients (71% of the total), were examined at least once with gadolinium enhancement. Fifteen of 24 patients (63%) underwent serial examinations during steroid therapy.

RESULTS A wide spectrum of findings was noted: white matter and periventricular high signal intensity on long-repetition-time/long-echo-time sequences, mimicking multiple sclerosis (11 patients); leptomeningeal enhancement (11 patients); brain parenchymal mass (seven patients)--six demonstrated enhancement, one did not receive contrast; lacrimal gland mass (three patients); hydrocephalus (three patients); enlarged ventricles, apparently atrophic (one patient); periventricular enhancement (three patients); extraaxial mass, mimicking meningioma (two patients); chiasmal enhancement or swelling (one patient); enhancing nerve roots (two patients); enlarged pituitary stalk (two patients); pontine infarct (one patient); and enhancing parenchymal spinal cord mass (three patients). Partial or complete resolution of the radiographic abnormality occurred in 13 of 15 cases (87%), which paralleled clinical improvement. No response was detected in the remaining two. Abnormal enhancement was the finding that was most responsive to steroid therapy, with response seen in nine of 10 patients with leptomeningeal enhancement, in six of six patients with enhancing brain parenchymal masses, in three of three patients with enhancing cord masses, and in all three patients with periventricular enhancement.

CONCLUSIONS 1) MR shows a spectrum of protean central nervous system abnormalities associated with neurosarcoidosis. 2) This high sensitivity for associated abnormalities aids in differentiating central nervous system sarcoid from the many diseases that it can mimic. In particular, enhancement was a useful clue to the diagnosis in 15 of 17 cases in which it was used (88%). 3) MR demonstrates regression of central nervous system abnormalities during steroid therapy, in particular abnormal meningeal, periventricular, and parenchymal enhancement.