Comparison of glucose-insulin-thallium-201 infusion single photon emissioncomputed tomography (SPECT), stress-redistribution-reinjection thallium-201 SPECT and low dose dobutamine echocardiography for prediction of reversible dysfunction

The usefulness of glucose-insulin-thallium-201 (GI-T1) infusion single phot on emission computed tomography (SPECT) in predicting reversible dysfunctio n has not been evaluated, so the present study recruited 20 patients with r egional ischemic dysfunction for investigation. All patients underwent GI-T 1 SPECT, post-stress T1 reinjection imaging and low dose dobutamine echocar diography. The diagnostic accuracy of these 3 techniques in predicting func tional recovery was evaluated by receiver operating characteristic (ROC) an alysis. In segments with functional recovery, regional T1 activities of GI- T1 SPECT were significantly higher than those of reinjection imaging (p <0. 05), although there were no significant differences in segments without rec overy. The area under the ROC curve for GI-T1 SPECT (0.75 +/-0.06) was grea ter than that for reinjection imaging (0.68 +/-0.07). The optimal cutoff va lues to identify viable myocardium were considered to be 55% of peak activi ty for GI-T1 SPECT and 50% for reinjection imaging. At this cutoff point, t he sensitivity and specificity for detection of functional recovery were, r espectively, 85% and 61% for GI-T1 SPECT, and 73% and 61% for reinjection i maging. Dobutamine echocardiography had the same sensitivity (85%), but low er specificity (48%) than GI-T1 SPECT. Continuous infusion of GI-T1 solutio n enhances regional TI uptake compared with conventional post-stress reinje ction imaging. This study suggests that GI-T1 SPECT is superior to reinject ion imaging and dobutamine echocardiography in predicting functional recove ry after ischemic left ventricular dysfunction.