STRESS AND REST MYOCARDIAL SPET QUANTIFICATION WITH TL-201 AND TC-99(M)-TETROFOSMIN - A COMPARISON

Tc-99(m)-tetrofosmin is a new myocardial perfusion agent that has exce llent physical and pharmacokinetic characteristics for performing tomo graphic myocardial perfusion studies. The aim of this study was to com pare the behaviour of Tc-99(m)-tetrofosmin and Tl-201 in the assessmen t of ischaemia and viability in patients with previous myocardial infa rction. Twenty consecutive patients who had suffered infarction and be en referred for assessment of ischaemia and myocardial viability were enrolled into the study. Each patient underwent two stress tests perfo rmed no more than 10 days apart, one with a Tl-201 exercise-reinjectio n-redistribution method and one with a Tc-99(m)-tetrofosmin short prot ocol (exercise-rest). The results were quantified using polar maps to represent images for stress, rest and reversibility. The poststress im ages showed there was a slight tendency to overestimate defect size wi th 99Tcm-tetrofosmin in the lateral region (P < 0.006). We found no si gnificant differences between the two tracers when comparing reversibi lity. The same defect sizes at rest were obtained when the maps for Tl -201 with uptake of 50% were compared with those for Tc-99(m)-tetrofos min with uptake of 45%. Agreement between the two agents for assessmen t of viability was 93%. We conclude that the quantitative assessment o f myocardial ischaemia and uptake of Tc-99(m)-tetrofosmin at rest are comparable to those obtained with Tl-201 in patients who have suffered myocardial infarction. ((C) 1998 Lippincott-Raven Publishers).