Reverse redistribution of technetium-99m-tetrofosmin after acute coronary revascularization in patients with myocardial infarction

This study qualified the severity and localization of reverse redistribution of technetium-99m(Tc)-tetrofosmin rest imaging. Both Tc-tetrofosmin and thallium-201 (Tl) rest imaging with early images and delayed images were obtained in the subacute phase of myocardial infarction in 21 patients with first anterior myocardial infarction and with successful transluminal angioplasty (including stenting). Relative myocardial uptake (%uptake), degree of reverse redistribution (%), and washout rate (%) were evaluated quantitatively in 6 left ventricular segments (inferoseptal, anteroseptal, anterior, anterolateral, lateral, inferolateral and inferior) by circumferential profile analysis. The percentage reverse redistribution in the infarct area was larger in Tc-tetrofosmin imaging than in Tl imaging (p=0.013). Reverse redistribution was most prominent in the anterior wall (anterior>anteroseptal>inferoseptal, p=0.020). This suggests that infradiaphragmatic scatter is unlikely as the mechanism of reverse redistribution. The washout rate of Tc-tetrofosmin in the infarct area (reverse redistribution area) was higher than that in the normal area (non-reverse redistribution area), and was also higher than the washout rate of Tl imaging in the infarct area. The %uptake of delayed images in the infarct area was larger in Tc-tetrofosmin than that in Tl imaging, whereas %uptake of early images did not differ. The percentage reverse redistribution did not correlate with the degree of collateral circulation and the residual stenosis. In conclusion, reverse redistribution of Tc-tetrofosmin was more prominent in the infarct area, and this was due to the relatively lower uptake of reverse redistribution of Tc-tetrofosmin than delayed Tl images. (author)