COMPARISON OF TC-99M Q12 AND TL-201 FOR DETECTION OF ANGIOGRAPHICALLY DOCUMENTED CORONARY-ARTERY DISEASE IN HUMANS

Background. 99mTc-labeled Q12 (99mTc-Q12) is a new imaging agent that produces myocardial visualization in humans. This study examined the hypothesis that a 100-minute rest-exercise tomographic imaging protocol after injection of 99mTc-Q12 can be used to detect the presence or absence of coronary artery stenoses. Methods and Results. Imaging with Tl-201 and 99mTc-Q12 was performed in 20 patients with angiographically documented coronary artery disease and 10 ''normal'' subjects including two patients with chest pain and normal coronary arteriograms and eight subjects with a very low likelihood of occlusive coronary disease. 99mTc-Q12 was imaged beginning 15 minutes after injection at rest and with exercise. In the 20 patients, a corresponding myocardial defect was detected in blinded fashion in 18 with Tl-201 and 17 with 99mTc-Q12 (difference not significant). Of 10 patients without evidence of coronary disease, nine had a normal Tl-201 scan and eight had a normal 99mTc-Q12 scan (difference not significant). Agreement of 99mTc-Q12 and Tl-201 imaging for detection of regional myocardial perfusion defects was excellent (kappa = 0.88). Identification of the presence or absence of angiographically documented coronary disease in individual coronary artery distributions was 80% and 82% for Tl-201 imaging and 73% and 87% for 99mTc-Q12 (difference not significant). Conclusion. 99mTc-Q12, used in a rest-exercise sequence that can be completed in 100 minutes, provided identification of regional myocardial perfusion defects similar to that of Tl-201.