Interpretation of reverse redistribution of 99mTc-tetrofosmin in patients with acute myocardial infarction

Reverse redistribution (RR) of technetium-99m tetrofosmin (TF) in patients with acute myocardial infarction (AMI) has been considered a sign of salvaged myocardium. We examined the time evolution of the RR pattern during a 6-month period and the clinical implications of RR. TF myocardial SPET was performed in 22 patients 1 week, 1 month and 3-6 months after AMI. Myocardial images were obtained 30 min and 180 min after the injection of TF. Regional uptake of TF was rated using a four-point scoring system. RR was defined as an increase of more than 1 point in the regional score on images obtained at 180 min. Echocardiography was performed to assess regional wall motion at the same time as TF imaging. RR observed at 1 week tended to disappear after 1 month and 3-6 months. The incidence of regional wall motion abnormality was reduced in patients with RR compared with that in patients with fixed defects. Recovery of abnormal regional wall motion occurred earlier in segments with disappearance of RR than in those without disappearance of RR. It is concluded that RR may reflect salvaged myocardium and that disappearance of RR may indicate earlier recovery of salvaged myocardium.