MR and CT in the evaluation of sarcoid myopathy

Sarcoid myopathy is a relatively rare extrapulmonary complication of sarcoidosis. We evaluated the diagnostic utility of MR at 1.5 T in four patients with sarcoid myopathy of the lower extremities established by biopsy. Two of the patients were of the "atrophic type" and two of the "nodular type." The findings on MR were compared with the findings on CT, gallium scanning, and electromyography. Only MR was positive in all cases. The T2-weighted scans (spin echo 2,000/80) revealed two distinctly different patterns of abnormality (i.e., discrete foci of high signal intensity lesions in the patients with the nodular type of sarcoid myopathy and atrophic muscle of high signal intensity in the patients with the atrophic type). Due to its ability to provide objective findings of the extent and distribution of muscle involvement, MR should prove useful in the detection, diagnosis, and monitoring of sarcoid myopathy.