Is quantitative analysis superior to visual analysis of planar thallium 201 myocardial exercise scintigraphy in the evaluation of coronary artery disease? - Analysis of a prospective clinical study

Quantitative analysis of myocardial exercise scintigraphy has been previously reported to be superior to visual image interpretation for detection of the presence and extent of coronary artery disease. Computer analysis of perfusion defects and washout rate of thallium 201 was performed on scintigrams from a group of 131 consecutive patients (prospective group), using criteria defined from a previous group of 72 patients (initial group), and compared with visual interpretation of scintigrams for detection and evaluation of coronary artery disease. The sensitivity of the quantitative technique with regard to overall detection of coronary artery disease was not significantly different from the visual method (69% and 74%, respectively), whereas the specificity was higher (86% and 68%). Quantitative analysis did not increase the sensitivity of thallium imaging over the visual method in the left anterior descending artery (46% vs 65%) and the right coronary artery (51% vs 72%) but did increase sensitivity in the left circumflex artery (75% vs 47%). Whereas in the initial group quantitative analysis resulted in a better identification of multivessel disease (sensitivity 81 % vs 57%), in the prospective group sensitivity decreased (54% vs 67%) without significant loss of specificity. The initial group had a 40% incidence of three-vessel disease and the prospective group, 22% (P < 0.05). One-vessel disease was higher in the prospective group (32% vs 11%, P < 0.05). Thus, assessing the quantitative technique in a larger prospective patient population, there was no improvement of detection of the presence and extent of coronary artery disease when compared with visual interpretation

Thallium-201 scintigraphy after dipyridamole infusion with low-level exercise. III Clinical significance and additional diagnostic value of ST segment depression and angina pectoris during the test

Intravenous dipyridamole thallium testing is a useful alternative procedure for assessing coronary artery disease (CAD) in patients who are unable to perform maximal exercise tests. Ischaemic ST segment depression and angina pectoris are frequently observed during the test, in particular when exercise is added to dipyridamole infusion. To establish the clinical significance and additional diagnostic value of these markers of ischaemia during dipyridamole low-level exercise testing (DXT) 57 patients with CAD (group A), 21 patients with normal or near-normal coronary arteries at coronary arteriography (group B), and 20 healthy subjects with low likelihood of CAD (group C) were studied. During DXT ischaemic ST segment depression was observed in 28 patients (47%) of group A and in two patients (10%) of group B. Angina pectoris was experienced by 35 patients (61%) of group A and by five patients (24%) of group B. The positive predictive value of both ST depression and angina pectoris was high (88 and 93%, respectively), but the negative predictive values were low (42 and 40%, respectively). Combining ST segment analysis with the findings of thallium imaging significantly increased the diagnostic accuracy of the test. ST segment depression, angina pectoris, and thallium abnormalities were highly specific findings if the study population consisted of asymptomatic subjects with a low likelihood of CAD (group C). Sensitivity for the detection of the presence of CAD increased with the extent of CAD for all parameters studied. Thus, ST depression and angina pectoris, alone or in combination, during DXT have little diagnostic significance, although sensitivity is increased in patients with triple-vessel CAD.(ABSTRACT TRUNCATED AT 250 WORDS