Comparison of teboroxime and thallium for the reversibility of exercise-induced myocardial perfusion defects.

To determine the optimal technique for the scintigraphic detection of exercise-induced myocardial perfusion defects, we compared teboroxime scanning to both stress/redistribution thallium imaging and the thallium reinjection method following exercise in 35 patients. The overall concordance for the presence of a perfusion defect between teboroxime and thallium scanning was 91% (p < 0.01) and 89% when teboroxime was compared with stress/reinjection thallium imaging (p < 0.01). More segments per scan with fixed defects were observed with redistribution imaging than with teboroxime or thallium reinjection (2.9 vs 2.0 vs 1.9; p < 0.02). Additionally, more transient defects were present with teboroxime than thallium, but less than with reinjection imaging. One half of the 52 fixed perfusion abnormalities on stress/redistribution thallium imaging demonstrated reversibility with both teboroxime imaging and thallium reinjection scanning, but less than 50% of these segments were concordant. Teboroxime allows for improved detection of reversible perfusion defects compared with stress/redistribution thallium scanning, but more ischemia is noted with thallium reinjection. The variation in the detection of segmental ischemic defects between teboroxime scintigraphy and thallium reinjection scanning probably reflects different physiologic properties and imaging protocols of these perfusion agents.