The relationship between reverse redistribution of 99mTc-tetrofosmin in sub-acute phase and left ventricular functional recovery in chronic phase in patients with acute myocardial infarction

Objective The purpose of this study was to clarify the relationship between reverse redistribution (RRD) of 99m Tc-tetrofosmin ( 99m Tc-TF) and left ventricular functional recovery in patients with acute myocardial infarction (AMI). Methods We studied 21 patients with AMI who underwent direct percutaneous coronary intervention (PCI). 99m Tc-TF-gated single-photon emission computed tomography (SPECT) was performed at rest in the sub-acute and chronic phases. Imaging data were acquired at 30 min (early images) and 3 h (delayed images) after injection. Defect score, regional relative uptakes of 99m Tc-TF (%uptake), and regional wall thickening (WT) were calculated using the 20-segment model. We measured left ventricular ejection fraction (LVEF) and defined ΔLVEF as change in LVEF. Summed defect score was calculated by adding the scores of 20 segments on early and delayed images. Summed washout score (SWS) was derived as the difference between early and delayed scores. We defined that SWS was more than 1 point as individual RRD (I-RRD). In each segment, regional RRD (R-RRD) in the sub-acute phase was calculated as %uptake on early images minus %uptake on delayed images in the sub-acute phase. ΔWT was defined as change in WT from the sub-acute phase to chronic phase. We defined that R-RRD and ΔWT were higher than 1SD on the control map as R-RRD (+) and change of WT (+). Results All patients were divided into two groups according to the presence of I-RRD. ΔLVEF was significantly higher in I-RRD (+) than in I-RRD (−) (14.5 ± 12.1 vs. 0.0 ± 3.9%, p