Reinjection as an alternative to rest imaging for detection of exercise-induced ischemia with thallium-201 emission tomography

Abstract

Exercise thallium-201 single photon emission computed tomography images were compared prospectively with 4-hour redistribution images, with 4-hour reinjection images, and with images obtained at rest on a separate day in 37 patients with documented coronary artery disease. Exercise images were abnormal in 35 patients (95%). On the basis of an improvement in thallium-201 distribution between exercise and nonexercise images, overall sensitivity for the detection of coronary artery stenosis was significantly higher with reinjection at 4 hours ( p < 0.05) or with a rest injection on a separate day ( p < 0.05) than with redistribution imaging (84%, 83%, and 70%, respectively). Reinjection and rest injection were positive more frequently in patients with a wall-motion abnormality (76% and 80%, respectively, vs 64% at redistribution; p < 0.05 for both) or with >90% stenosis (77% and 76%, respectively, vs 58% at redistribution; p < 0.05 for both). Among the 11 patients who had no evidence of redistribution at 4 hours, five (45%) demonstrated ischemia with reinjection and five demonstrated ischemia in the separate rest study; a total of seven patients showed improvement either at reinjection or rest. Among these 86% had a wall-motion abnormality associated with stenosis of >90%, whereas in the other 30 patients these two conditions were observed concomitantly in only 43%. This study demonstrates that the thallium-201 4-hour postexercise reinjection technique is as sensitive as the 2-day rest/exercise method for the detection of coronary artery stenosis and provides additional information when a severe stenosis is associated with a wall-motion abnormality.