The role of99Tcm-tetrofosmin myocardial perfusion scintigraphy in the assessment of patients with previous myocardial infarction: A comparative study with201T1

The aim of this study was to determine the utility of 99Tcm-tetrofosmin cardiac imaging in patients with previous myocardial infarction and with significant coronary artery disease (CAD) compared with that of 201T1 cardiac imaging. Sixteen patients (14 males, 2 females) were studied by same-day exercise-rest 99Tcm-tetrofosmin imaging and exercise, rest and reinjection 201T1 cardiac imaging. For each study, semiquantitative visual analysis was performed in 20 segments using a 4-point scale. The regional distribution and defect reversibility with the two tracers were compared with the results of coronary angiography. A total of 320 segments were analysed. There was a statistically significant concordance between the numbers of fixed and reversible segments in both studies in myocardial segments supplied by totally occluded coronary arteries (Group 1), as well as in segments supplied by significantly stenosed coronary vessels (Group 2). The exercise and rest uptake of both 99Tcm-tetrofosmin and 201T1 in myocardial segments supplied by totally occluded coronary arteries with poor collateral flow was significantly lower compared with segments supplied by totally occluded coronary arteries with efficient collateral flow (P < 0.05). When the uptake of both tracers was analysed according to each major vascular territory, the mean exercise and rest uptake grades of 99Tcmtetrofosmin and 201T1 were similar. There was also no significant difference in defect reversibility between the two tracers. Discordant results were observed in the territory of the right coronary artery in Group 1 (mean exercise grade of 99Tcm-tetrofosmin = 2.26 ± 0.7 and of 201T1 = 1.92 ± 0.8; P 0.001) and in Group 2 (mean grade of 99Tcm-tetrofosmin = 0.79 ± 0.65 and of 201T1 = 0.95 ± 0.65; P 0.05). The results of the present study indicate that the overall diagnostic utility of 99Tcm-tetrofosmin in the identification of individual stenosed vessels is comparable with 201T1 in both patients with totally occluded coronary arteries and those with significantly stenosed vessels. The regional distribution of both tracers was lower in myocardial segments supplied by totally occluded coronary arteries with poor collateral flow. © 1998 Chapman and Hall Ltd.