ccurate detection of dysfunctional but viable myocardium has become an important component of the clinical assessment of patients with ischemic left ventricular dysfunction. Several noninvasive modalities, including positron emission tomography (PET) with fluorine-18 fluorodeoxyglucose 1,2 thallium-201 (Tl) singlephoton emission computed tomography (SPECT) and dobutamine echocardiography, [3][4][5][6][7][8] have been developed during the past decade to detect myocardial viability, but recent studies have suggested that stress-redistribution-reinjection imaging, 7-10 rest-redistribution imaging, 6,11-14 rest technetium-99m sestamibi 12 and tetrofosmin SPECT 13 identify viable myocardium better than stress redistribution imaging. PET is still recognized as a more reliable method to evaluate myocardial viability than SPECT, but because PET is not commonly available, it is necessary to develop a more accurate and convenient method for detecting viable myocardium using SPECT. In 1993, Tartagni et al found that continuous infusion of Tl with a low dose of insulin in a glucose -potassium solution enhanced the cellular uptake Japanese Circulation Journal Vol.65, December 2001 of the radiotracer in severely ischemic regions, 15 but little is known about the usefulness of this method in predicting functional recovery. The present study was designed to (1) compare the regional Tl uptake between glucose -insulinTl (GI-Tl) infusion SPECT and reinjection imaging; and (2) compare the accuracy of predicting of functional recovery by GI-Tl SPECT, reinjection imaging and low-dose dobutamine echocardiography in the same patients.
Methods
PatientsPatients with coronary artery disease and resting regional left ventricular dysfunction were screened for enrolment in the study. Patients with unstable angina, uncontrolled heart failure, atrial fibrillation, and technically inadequate echocardiographic images were excluded. Twenty patients (17 men, 3 women; mean age, 66 years; Table 1) constituted the final study group. All patients had regional wall motion abnormalities on rest echocardiography: 14 patients had acute myocardial infarction (AMI <4 weeks before the study), 6 had stable angina pectoris with (n=3) or without (n=3) a previous (>6 months) MI. Of the 14 patients with AMI, 10 underwent primary percutaneous transluminal coronary angioplasty within 12 h of the onset of symptoms. Repeat angiography in the chronic phase revealed significant (≥75%) restenosis in 1 of the 10 patients, who then The usefulness of glucose -insulin -thallium-201 (GI-Tl) infusion single photon emission computed tomography (SPECT) in predicting reversible dysfunction has not been evaluated, so the present study recruited 20 patients with regional ischemic dysfunction for investigation. All patients underwent GI-Tl SPECT, post-stress Tl reinjection imaging and low dose dobutamine echocardiography. The diagnostic accuracy of these 3 techniques in predicting functional recovery was evaluated by receiver operating characteristic (ROC) analysis. In segments ...