[Myocardial scintigraphy using technetium-99m labelled methylene diphosphonate in coronary care units. 82 cases]

Many isotopic methods have been proposed recently for the investigation of normal and diseased myocardium in ischaemic heart disease. The results of myocardial scintigraphy with Technetium 99 m marked methylene diphosphonate in the supine, left lateral and 30 degrees or 45 degrees right anterior oblique incidences are reported. A preliminary study of the tracer's fixation on diseased myocardium was performed in 18 patients. Scintigraphy every 30 minutes over a five hour period showed the optimal time for investigation to be situated between the third and fourth hour after the injection of the tracer. Seventy eight patients were then investigated; 82 scintigraphies were performed, 58 in patients with acute myocardial infarctions confirmed by the usual biological and electrocardiographic changes. A 74% sensitivity and 67% specificity were obtained with the methylene diphosphonate method. These figures varied according to the type of necrosis, subendocardial or transmural and with its extent, chronicity and degree of CPK elevation. Methylene diphosphonate scintigraphy would appear to be less sensitive and more specific for diseased myocardium than other isotopic methods. It may be carried out at the bedside and could improve the diagnosis of acute myocardial infarction when the clinical history and electrocardiographic changes are difficult to interpret.