Quantitative Rest Technetium-99m Tetrofosmin Imaging in Predicting Functional Recovery After Revascularization: Comparison With Rest–Redistribution Thallium-201

Objectives. This study was undertaken to 1) compare the regional myocardial tracer distributions between rest technetium (Tc)-99m tetrofosmin and rest–redistribution thallium (Tl)-201 images in patients with coronary artery disease and left ventricular dysfunction; and 2) assess the comparative values of these agents for predicting functional recovery after revascularization. Background. Tc-99m tetrofosmin is new myocardial perfusion imaging agent, but its role for detecting viable myocardium is still unclear. Methods. Thirty-six patients with coronary artery disease and left ventricular dysfunction underwent rest Tc-99m tetrofosmin, rest–redistribution Tl-201 and gated blood pool scintigraphy. In 21 patients with successful revascularization confirmed by follow-up angiography, gated blood pool scintigraphy was repeated after revascularization. Optimal threshold cutoffs to separate reversible from irreversible dysfunction were determined by receiver operating characteristic analysis. Results. Regional Tc-99m tetrofosmin activity highly correlated with redistribution Tl-201 activity (r = 0.93). The diagnostic performance for predicting functional recovery, as measured by the are under the receiver operating characteristic curves, measured 0.66 ± 0.07 (mean ± SD) for Tc-99m tetrofosmin and 0.67 ± 0.07 for Tl-201 (p = 0.60, 96.7% power to detect difference in are of 0.10). The optimal threshold cutoffs for viability were considered to be 50% of peak activity for Tc-99m tetrofosmin and 55% of peak activity for Tl-201. The positive and negative predictive values for reversible dysfunction were, respectively, 69% and 82% for Tc-99m tetrofosmin and 69% (p = 0.99 vs. Tc-99m tetrofosmin) and 71% (p = 0.66 vs. Tc-99m tetrofosmin) by Tl-201. Conclusions. The diagnostic performance of quantitative rest Tc-99m tetrofosmin imaging in predicting functional recovery after revascularization is comparable to that of rest–redistribution Tl-201.