Detection of ventricular thrombosis in acute myocardial infarction: Value of indium-111 platelet scintigraphy in relation to two-dimensional echocardiography and clinical course

In order to detect left ventricular (LV) thrombosis, 111In-platelet scintigraphy and two-dimensional echocardiography were performed in 40 patients 15 days ±6 days after acute myocardial infarction. A dual isotope subtraction method, using 111In-platelet scintigraphy and 99mTc-blood pool scintigraphy, was used to assess LV platelet deposition expressed as LV counts per pixel. Seven patients (group A) had a positive 111In-platelet scintigram and 33 patients (group B) had a negative 111In-platelet scintigram (LV counts per pixel: 0.56±0.23 and 0.28±0.19, respectively, P<0.05). Three group A patients but no group B patients had a positive echocardiogram. Arterial embolism was noted in four patients, of whom two showed both positive echocardiogram and platelet scintigram. LV counts per pixel were 0.57±0.13 and 0.31±0.21, respectively (P<0.02) in patients with and without arterial embolism. Thus, both 111In-platelet scintigraphy and two-dimensional echocardiography can detect LV thrombosis. 111In-platelet scintigraphy may help to define patients at risk for embolization and may be used in conjunction with echocardiography to study the effect of antithrombotic therapy. (orig.)