111In monoclonal antimyosin antibody imaging: Imaging of myocardial infarction and myocarditis.

A new scintigraphic method to detect myocardial necrosis has been developed using antimyosin monoclonal antibody Fab labeled with indium-111. Using this method, we studied 35 patients with myocardial infarction, 5 patients with myocarditis and 3 patients with angina pectoris. 111In antimyosin Fab was administered intravenously and antimyosin images were recorded by planar and single photon emission computed tomography (SPECT) 48 hours after injection. Planar images showed discrete localization of 111In antimyosin in 25 of 26 patients within 14 days after the onset of acute myocardial infarction. In 14 of these patients creatine kinase, glutamic oxaloacetic transaminase and lactic dehydrogenase had already normalized. Positive scans were also obtained in 6 of 12 patients between the third week to the ninth year after the onset of the disease. Three patients with acute myocarditis had positive scans 2 and 4 weeks after the onset of the disease. Thus, 111In antimyosin imaging may be a useful noninvasive method for the diagnosis of coronary diseases and myocarditis. Although the mechanism of persistent positive antimyosin images in the chronic stage remains to be clarified, 111In antimyosin scintigraphy holds potential promise as a non-invasive method for the detection of myocardial injury in the subacute to chronic stage as well as in the acute stage.