Thallium-201 scintigraphy in diagnosis of coronary stenosis. Comparison with electrocardiography and coronary arteriography.

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Abstract
The sensitivity of rest and exercise 201Tl scintigraphy for the detection of significant coronary artery disease and myocardial ischemia was compared with rest and exercise ECG in 46 patients with chest pain. Of 26 patients with greater than 70% coronary stenosis, 16 had abnormal rest 201Tl scintigrams and 13 had Q waves. Myocardial perfusion defects in the resting scintigram correlated with evidence of previous myocardial infarction (16 of 17 patients, 94%), significant Q waves were present in 13 of these 17 patients (76%). After exercise abnormal 201Tl scintigrams consistent with ischemia were found in 21 patients (81%). Abnormal exercise ECG were present in 15 patients (58%). The combination of abnormal exercise 201Tl scintigrams or exercise ECG (23/26, 88%) exceeded abnormal exercise ECG alone (15/26, 58%). The 2 procedures were complementary. Abnormal rest or exercise 201Tl scintigrams were obtained in 25/26 patients (96%) compared with abnormal rest or exercise ECG in 21/26 patients (84%). Patients (20) with < 50% coronary stenosis had normal rest 201Tl scintigrams and no Q waves. Two had abnormal exercise 201Tl scintigrams and 7 had abnormal exercise ECG. Exercise Tl scintigraphy has higher sensitivity than exercise ECG in detecting exercise induced ischemia and is more specific. Scintigraphy appears to have a higher sensitivity than ECG in detecting coronary artery disease. While each of the patients with triple vessel coronary disease had positive exercise perfusion scintigrams and positive exercise ECG, the 201Tl scintigram was more sensitive than the rest or exercise ECG in patients with single vessel disease. The correlation of Tl perfusion defects at rest and/or exercise with angiographically significant coronary stenosis was higher for the left anterior descending and right coronary arteries than for the circumflex coronary artery.