CLINICAL-SIGNIFICANCE OF REVERSE REDISTRIBUTION ON 24-HOUR DELAYED IMAGING OF EXERCISE TL-201 MYOCARDIAL SPECT - COMPARISON WITH MYOCARDIALFLUORINE-18-FDG-PET IMAGING AND LEFT-VENTRICULAR WALL-MOTION

Clinical significance of reverse redistribution on 24-hr delayed image s after exercise Tl-201 myocardial SPECT was investigated in 16 patien ts with recent myocardial infarction. Methods: Findings of 24-hr delay ed Tl-201 SPECT imaging were compared with those of glucose-loaded F-1 8-fluorodeoxyglucose (FDG) imaging by myocardial PET and with left ven tricular wall motion obtained by bi-plane contrast left ventriculograp hy. In each patient, transaxial thallium images and corresponding F-18 -FDG images were divided into five ROIs. Results: Reverse redistributi on was found in 15 of 80 regions, The mean FDG activity score in regio ns with reverse redistribution was significantly lower than that in re gions having normal or slightly decreased thallium activity on 24-hr d elayed imaging; it was significantly higher than that in regions havin g severely decreased or no thallium activity on 24-hr delayed imaging. The mean wall motion score in regions with reverse redistribution was significantly lower than in regions with normal or slightly decreased thallium activity, however, it was significantly higher than that in regions with moderately or more decreased thallium activity. Conclusio n: These findings demonstrate that in regions showing reverse redistri bution on 24-hr delayed Tl-201 imaging, myocardial exogenous glucose u tilization and left ventricular wall motion had deteriorated, but were not on a level with the scar.