MYOCARDIAL PERFUSION IMAGING WITH TECHNETIUM-99M-TC NOET - COMPARISONWITH TL-201 AND CORONARY ANGIOGRAPHY

We compared TcN-NOET [bis(N-ethoxy, N-ethyl dithiocarbamato)nitrido (T C)-T-99m] and Tl-201 images to estimate the utility of this compound i n the detection of coronary artery disease (CAD). Methods: Twenty-five patients undergoing cardiac catheterization had stress-redistribution -reinjection Tl-201 SPECT imaging, stress-delayed (2, 4 and 6 hr posti njection) and rest-delayed (4 hr postinjection) TcN-NOET SPECT imaging . Results: Nineteen patients had coronary stenosis greater than or equ al to 50% and six were normal. Stress TcN-NOET and Tl-201 imaging were concordant for the presence of CAD in 22/25 patients (88%, kappa = 0. 76 +/- 0.20). The overall sensitivity of TcN-NOET SPECT imaging was 74 % (14/19 patients) and 68% (13/19 patients) for Tl-201 SPECT imaging. The specificity was 100% (6/6 patients) for both techniques. The overa ll agreement of TcN-NOET and Tl-201 for the presence of disease in ind ividual coronary arteries was 96% (72/75 arteries, kappa = 0.92 +/- 0. 16). Segmental analysis of stress images showed a concordance in 211/2 25 segments (94%, kappa = 0.82 +/- 0.09). Comparison of the 4-hr image s showed a concordance between Tl-201 and TcN-NOET in 21/23 patients. Following TcN-NOET injection at rest, seven patients had a defect on t he initial images, which had normalized 4 hr postinjection in four pat ients (57%). Conclusion: Perfusion imaging with TcN-NOET and Tl-201 gi ves comparable diagnostic information in patients undergoing exercise testing for assessment of CAD. Because of the normalization of myocard ial activity 4 hr after injection in some patients, we conclude that T cN-NOET is a potential technetium compound equivalent to Tl-201.