Exercise 201Tl scintigraphy: evaluation of the additional diagnostic value

The additional diagnostic yield of exercise 201Tl scintigraphy using both visual and quantitative analysis was determined in 221 patients with known or suspected coronary artery disease (CAD). The coronary arteriogram was adopted as the gold standard. After pretest clinical and exercise electrocardiographic data were taken into consideration, scintigraphy added diagnostic accuracy both in the diagnosis of CAD and of multivessel disease. The diagnostic yield of the scintigraphy in terms of sensitivity and specificity was, however, not significant. In 79% (121/153) of the patients, the diagnosis of the presence, or exclusion, of CAD was highly probable (P > 0.80 or P < 0.20) when considering clinical and exercise data. The diagnosis was, however, not significantly improved by the scintigraphic result. Twenty-seven per cent (20/73) returned a negative scintigraphic results with a high (P > 0.80) prescintigraphic probability for CAD and a positive arteriogram. It was concluded that 201Tl scintigraphy has additional diagnostic value after clinical and exercise parameters were taken into consideration in the diagnosis of coronary artery and multiple vessel disease. It is not recommended to refer patients with either a low or high probability of CAD for screening and diagnosis as in a high proportion of patients the diagnosis of CAD could have been made using clinical or exercise data alone.