A clinicopathologic correlation study of Thallium-201 myocardial scintigraphy in diagnosis of myocardial infarction.

In a series of 1,000 consecutive autopsy cases, we evaluated the clinical utility of thallium-201 (Tl-201) myocardial scintigraphy and electrocardiography (ECG) in 101 patients who had been studied while alive. Fifty-five cases had myocardial infarctions (MI) at autopsy. The Tl-201 scintigram and ECG in diagnosis of MI showed sensitivities of 68% and 60%, specificities of 87% and 83%, and diagnostic accuracies of 76% and 70%, respectively. The sensitivity of the Tl-201 scintigram was 70% in anterior MI, 80% in postero-inferior MI, 25% in lateral and subendocardial infarction. The sensitivity was 88% for large massive MI, but was low in scattered (50%) or middle-sized MI (17%). The diagnostic limit of the resolution of Tl-201 scintigrams was 4.5 cm in long diameter. All 8 cases with MI of less than 4 cm could not be diagnosed with the technique. There were 48 cases of large MI (more than 5 cm), but 8 cases could not be diagnosed by scintigraphy because of non-transmural or scattered MI. A comparison of the Tl-201 scintigram and ECG showed that 27 cases out of 60 cases were diagnosed by both methods, 14 only by the Tl-201 scintigram, 9 only by ECG and 10 by neither method.