Clinical significance of reverse redistribution on 24-hour delayed imaging of exercise thallium-201 myocardial SPECT: comparison with myocardial fluorine-18-FDG-PET imaging and left ventricular wall motion.

UNLABELLED

Clinical significance of reverse redistribution on 24-hr delayed images after exercise 201Tl myocardial SPECT was investigated in 16 patients with recent myocardial infarction.

METHODS

Findings of 24-hr delayed 201Tl SPECT imaging were compared with those of glucose-loaded 18F-fluorodeoxyglucose (FDG) imaging by myocardial PET and with left ventricular wall motion obtained by bi-plane contrast left ventriculography. In each patient, transaxial thallium images and corresponding 18F-FDG images were divided into five ROIs.

RESULTS

Reverse redistribution was found in 15 of 80 regions. The mean FDG activity score in regions with reverse redistribution was significantly lower than that in regions having normal or slightly decreased thallium activity on 24-hr delayed imaging; it was significantly higher than that in regions having 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.

CONCLUSION

These findings demonstrate that in regions showing reverse redistribution on 24-hr delayed 201Tl imaging, myocardial exogenous glucose utilization and left ventricular wall motion had deteriorated, but were not on a level with the scar.