The Value and Limitation of Thallium Scintigraphy in the Detection of Individual Coronary Artery Disease

Abstract

INTRODUCTION:

Exercise Thallium Scintigraphy is being used increasingly to evaluate patients with suspected or known coronary artery disease. Although several studies have now shown stress thallium scanning to be more sensitive than exercise tolerance test (E.T.T) for detecting patients with ischaemic heart disease, (1,2) much less is known about the value of the technique for identifying narrowings in the individual coronary arteries (3,4). The sensitivity of S.T.I in the identification of individual coronary arterial lesions (Table WIT) in our series of 35 patients (10 patients had single vessel disease only) showed a relatively higher value for R. C. A lesions which is in contradist inction to previous reports (3,4). The probable reason is the inclusion of relatively more cases of inferior infarcts. The sensitivity of localizat ion of lesions for LAD and left circumflex is in close correlation to the earlier studies. (5,6).

DISCUSSION:

In our patients with significant coronary artery disease the frequency of abnormal rest or post-exercise scintigrams was 100% a figure slightly higher than previous reports. The high value undoubtedly reflects our patient populat ion, which included a large number of patients with previous infarcts and with severe arterial lesions. In single vessel lesions the sensitivity of TL2O1 Scan is much higher in the localization of individual coronary artery lesions as compared to multiple vessel disease. The sensitivity for localization improves as the number of diseased vessels decreases (10, 11, 13).