On the clinical value of thallium 201 myocardial scintigraphy with special consideration of Bayes' theorem

304 patients (263 men, 41 women) at ages 21-69 years were studied by means of thallium 201 myocardial scintigraphy as well as by coronary angiography and laevography between the years 1978 and 1982. As a result of the coronal angiographic findings alone 146 patients (48%) were found to have coronary heart disease with lumen constrictions of 75%, and 194 patients (64%) with over 50% constriction. The thallium scintigraphy delivered quite positive results (96%) with patients with stenoses of greater than 75% and with patients with stenoses of greater than 50% it was still high (92%). The observation of individual vessels shows that LM-, RIVA- and RCA-constrictions can be diagnosed with an approximately similar sensitivity (83-89%), whereas for the RCX-constrictions, as by other authors, a clearly poorer value is found (54,1%). The view expressed by several authors, that 3-vessel diseases as a result of nonhomogeneous reduced deposition are not comprehensible by thallium scintigraphy, could be refuted. The relatively poor specificity we believe for one thing was as a result of the high disease prevalence in our group of patients. For another, the somewhat rigid limit definitions between hemodynamic effectiveness and non-effectiveness seemed to negatively influence the specificity. With the inclusion of patients with less stenosis in combination with pathological laevographs the value increased to 80,0%. (orig./MG)