Quantitative Thallium-201 Exercise Scintigraphy for Detection of Coronary Artery Disease

In 140 patients with chest pain quantitation of regional myocardial TI-201 activity was performed by serial scintigraphic images after treadmill exercise. Criteria for an abnormal thallium scintigram included: (a) greater than or equal to 25% persisted reduction in TI-201 uptake in anterolateral, anteroseptal, posterolateral, and inferoapical segments, or greater than or equal to 35% reduction in the inferior segment; (b) an initial defect with delayed redistribution; and (c) abnormal TI-201 washout. Of 110 patients with significant coronary artery disease (CAD), 100 had abnormal TI-201 scintigrams, while 27 of 30 patients with angiographically normal coronary arteries had normal scintigrams; 91% sensitivity, 90% specificity, and 97% predictive accuracy. Sensitivity and specificity were not significantly different when the 95 patients with diagnostic (greater than or equal to 85% maximum heart rate) and 45 with inconclusive (less than or equal to 85% maximum HR) Ex tests were compared. Comparison of qualitative and quantitative image analyses in a subset of these patients showed that both specificity and multivessel disease prediction were greater when the quantitative approach was used (90 against 73% and 78 against 39%, respectively). Sensitivity for CAD detection was reduced by 10% with visual interpretation alone. Thus, quantitative exercise TI-201 scintigraphy appears highly sensitive and specific for CAD detection in patients with chest pain.