The Clinical Value Of Myocardial Perfusion Imaging With ～(99m)TcN-NOET In Diagnosis Of Coronary Artery Disease

Background: 99mTcN-NOET[bis(N-ethoxy, N-ethyl dithiocarbamato)nitrido technetium-99m( V)] is a new neutral lipophilic 99mTc-labeled myocardial perfusion agent with a high first-pass extraction fraction and delayed redistribution kinetics after transient ischemia comparable to what is observed with 201T1. Currently, this compound is in phase III clinical trials in Europe. The purpose of this study was to estimate the utility of this agent in the detection of coronary artery disease (CAD). Methods: 10 normal volunteers, 1 myocardial infarction patients and 39 suspected CAD patients underwent stress-delayed (2 and 4 hr postinjection) 99mTcN-NOET myocardial perfusion imaging, and the heart-lung ratio (HLR) at different time was calculated. 13 patients of them accepted the coronary angiography examination in 2 months post myocardial imaging. Result: According to the exercise heart-lung ratio (EXHLR), 50subjects were divided into 2 groups. G1 (n=36, EXHLR > 2) contained 10 normal volunteers and 5 patients with normal coronary arteries. The other 21 subjects had no relevant symptom and cardiac event (defined as sudden cardiac death, non-fatal myocardial infarction and angina) occurred during the follow-up period of 4 to 12 months. All images of Gl were normal and the quality of the images was good. In G2 (n=14, EXHLR<2), the image of the patient with inferior infarction (double-vessel disease) was fixed defect. Three patients with CAD had complete reversible perfusion defects and two of them were confirmed by coronary angiography (one was single-vessel disease the other was double-vessel disease) and the other one was stable angina patient. The image of the patient with critical stenosis in three vessels was partly reversible perfusion defect. There was significantdifference between the HLR of the two groups at different time, the HLR of G2 was lower than G1 . The quality of all images of G2 was worse than G1 . Nine patients of G2 had normal perfusion images, four of them had significant CAD by qualitative coronary angiography (stenosis 50%-70%), three had angina during the follow-up period. Conclusion: 1 . Stress-delayed myocardial perfusion imaging with 99mTcN-NOET can be used to diagnose CAD and distinguish ischemic myocardium from scar. 2. Exercise-induced increases in pulmonary uptake of 99mTcN-NOET and descent of the HLR are associated with exercise-induced myocardial dysfunction. 3. The HLR may be as an index of the patients with CAD.