Value of the 201-Thallium scintigram in the diagnosis of coronary artery disease in patients with and without myocardial infraction

The usefulness and limitations of the 201-thallium scintigram in the detection of myocardial hypoperfusions is dependent on the sensitivity, specificity and predictive value of the method. The presence of myocardial hypoperfusion can be diagnosed with certainly from a pathologic scintigram only in the absence of false positive scintigrams. Such a high specificity can be achieved only by desginating markedly positive scintigrams as pathologic findings. This, however, necessarily incurs a reduction in sensitivity. In coronary artery disease with previous myocardial infarction, the sensitivity is primarily dependent on the extent of infarction. In coronary arterx desease with no previous myocardial infarction, the sensitivity of the thallium scintigram in patients with 2-vessel disease was found to be less than that of those with 1-vessel disease and 3-vessel disease. As compared with the exercise ECG, the scintigram was more sensitive only in patients with 1-vessel but less sensitive in those patients with 2-vessel and 3-vessel disease. The thallium scintigram is indicated for patients with atypical chest pain, when angina pectoris cannot be ruled out and when the exercise ECG is borderline or non-interpretable. The thallium scintigram is also indicated for asymptomatic patients with a markedly positive exercise ECG. The thallium scintigram yields no additional information relative to the question of presence or absence of myocardial hypoperfusion in patients with typical angina pectoris. In patients with a history of, but with no electrocardiographic criteria for myocardial infarction, the scintigram seems to be of only limited valued. The thallium scintigram is a valuable adjunct in the assessment of the results of coronary artery bypass surgery provided that a pre-operative study is available for comparison. (orig./MG)