Central nervous system sarcoidosis: Follow-up at MR imaging during steroidtherapy

PURPOSE: To document the changes observed at sequential magnetic resonance (MR) imaging of sarcoidosis lesions of the central nervous system (CNS) dur ing treatment with corticosteroids. MATERIALS AND METHODS: The abnormalities detected in 24 patients (mean foll ow-up, 36 months) were compared before and after therapeutic periods (n = 7 5) that were divided into attack (high-dose), upkeep (decreased-dose), and minimal (low-dose) periods. Parenchymal lesions were classified as type 1 ( enhanced with gadolinium), type 2 (demyelinating), or type 3 (lacunar) and were assessed as regressing, stable, or progressing. RESULTS: Seven of the 24 patients had several types of lesions. Isolated ty pe 3 lesions (six patients) were the only lesions not associated with neuro logic deficit. Type 1 lesions (13 patients) regressed in 22 of 22 attack pe riods and progressed in nine of 27 upkeep and minimal periods. MR imaging d epicted relapses in patients with multifocal CNS involvement or long-standi ng CNS impairment or in those who had previously received steroid therapy. Type 2 (seven patients) and type 3 (13 patients) lesions remained stable in 68 of 68 therapeutic periods. Type 1 lesions appeared in three patients wi th type 2 and type 3 lesions during two upkeep and three minimal periods. F indings at follow-up MR imaging contributed to the reintroduction of high-d ose corticosteroid therapy in eight patients. CONCLUSION: MR imaging can be used to differentiate between reversible and irreversible lesions in CNS sarcoidosis. MR imaging can be a useful tool fo r adjusting treatment to prevent irreversible CNS damage.