TECHNETIUM-99M-TETROFOSMIN REGIONAL MYOCARDIAL UPTAKE AT REST - RELATION TO SEVERITY OF CORONARY-ARTERY STENOSIS IN PREVIOUS MYOCARDIAL-INFARCTION

The aim of this study was to assess the potential role of Tc-99m-tetro fosmin cardiac tomography in detecting totally occluded or severely st enosed coronary arteries. Methods: Thirty-three patients (32 men, 1 wo man; mean age, 52 +/- 9 yr) with chronic coronary artery disease (CAD) and left ventricular dysfunction (ejection fraction 40% +/- 12%) unde rwent resting Tc-99m-tetrofosmin SPECT and coronary arteriography with in 2 wk. Regional distribution of Tc-99m-tetrofosmin activity was comp ared with the coronary anatomy. Tracer uptake was quantitatively analy zed in 22 segments for each patient. The activity in each segment was expressed as a percent of the peak activity. Results: A significant re lationship between the degree of coronary artery stenosis and Tc-99m-t etrofosmin uptake was observed (rho = -0.64, p < 0.001). Technetium-99 m-tetrofosmin uptake was lower (p < 0.001) in segments with 100% coron ary occlusion with poor collateral flow (53% +/- 17%) compared to segm ents supplied by a vessel with 50%-99% coronary stenosis (75% +/- 20%) or a normal noncritically stenosed artery (85% +/- 10%). Furthermore, Tc-99m-tetrofosmin uptake was lower (p < 0.01) in segments with 100% coronary occlusion with poor (53% +/- 17%) compared to those with good collateral flow (70% +/- 20%). Conclusion: These results demonstrate that quantitative analysis Of resting Tc-99m-tetrofosmin regional upta ke detects the majority of segments supplied by occluded coronary arte ries with poor collateral flow and suggest that this tracer may be hel pful in the diagnosis of acute myocardial infarction.