Indium-111-antimyosin Fab imaging to demonstrate myocardial involvement in systemic lupus erythematosus.

Indium-111-antimyosin Fab imaging has been used to indicate myocardial injury. This report describes antimyosin accumulation in two patients with myocardial involvement in systemic lupus erythematosus. Both patients complained of chest pain, and significant stenoses of extramural coronary arteries were ruled out by angiography. The first patient, a 64-yr-old woman, had immunopathologic findings suggestive of systemic lupus. Indium-111-antimyosin Fab imaging showed myocardial tracer uptake. This prompted endomyocardial biopsy providing evidence of systemic lupus. The patient improved under immunosuppressive therapy. The second patient, a 47-yr-old man, had systemic lupus diagnosed by immunopathologic findings and skin biopsy. He had evidence of pericarditis on electrocardiography and echocardiography. Indium-111-antimyosin Fab imaging demonstrated additional myocardial involvement, which supported the initiation of immunosuppressive therapy. Our results suggest that 111In-antimyosin Fab imaging may provide valuable diagnostic information and influence patient management in systemic lupus erythematosus with suspected myocardial involvement.