Usefulness of Dual SPECT With Tc-99m Pyrophosphate and Tl-201 To Predict Further Events After Acute Myocardial Infarction With Single-Vessel Coronary Artery Disease

PURPOSE: This study was undertaken to determine whether the findings of dual SPECT with Tc-99m pyrophosphate (PYP) and Tl-201 were predictive of further cardiac events after acute myocardial infarction. METHODS: The authors evaluated 88 patients with acute myocardial infarction who underwent dual SPECT for single-vessel coronary artery disease. RESULTS: Twenty-nine patients showed overlapping of Tc-99m PYP and Tl-201 in the same location (overlap-positive group), and 59 patients had no overlap (overlap-negative group). In patients in the overlap-positive group, the incidence of subsequent events was significantly higher than in patients in the overlap-negative group (P < 0.001). In the overlap-positive group, the number of overlap segments in patients with further events was significantly greater than that in patients without further events (P < 0.005). CONCLUSIONS: Areas with overlapping of Tc-99m PYP and Tl-201 may contain jeopardized myocardium. These results suggest that patients who have a Tc-99m PYP and Tl-201 overlap-negative scan are a low risk group, whereas patients who have more overlapping segments may require catheterization and revascularization. Thus simultaneous SPECT imaging with Tc-99m PYP and Tl-201 might be useful to identify patients with greater ischemic risk after acute myocardial infarction.