Sensitivity and specificity of exercise-examinations of the heart using Tl-201 and SPECT imaging

To assess the sensitivity and specificity of myocardial SPECT using Tl-201, 94 patients were studied twice, i.e. immediately following maximum exercise and 3 hours thereafter. Coronary heart disease (CHD) was confirmed by coronary angiography in 78 patients and excluded in 16 patients. In the discrimination 'diseased/non diseased' a sensitivity of 92% was achieved. The subdivision into groups - (a) with a history of myocardial infarction, and (b) without infarction - yielded sensitivities of 92% and 87%, respectively. The specificity was 87%. Refering to segments (anterior and posterior segment) the sensitivity was 86% in group (b) and as much as 98% in group (a). The specificity amounted to 94%. Within the segments, the following 3 patterns were distinguished (1) redistribution as a sign of transient ischaemia, (2) a persisting defect as a sign of scar tissue and/or severe ischaemia, and (3) a persisting defect and redistribution within one segment. The segment evaluation yielded false-negative results in multivessel diseases as a result of limited exercise tolerance. (orig.)