The Canadian exercise technetium 99m-labeled teboroxime single-photon emission computed tomographic study

Background: ^99mTc-labeled teboroxime undergoes rapid washout from the myocardium. For this reason, its use has been favored in conjunction with pharmacologic stress, which enables patient positioning before tracer administration, and multidetector single-photon emission computed tomography (SPECT), which enables rapid acquisition. We evaluated treadmill exercise ^99mTc-labeled teboroxime SPECT with single-detector systems for the detection of coronary artery disease. Methods and Results: Treadmill exercise ^99mTc-labeled teboroxime SPECT was compared with analogous ²⁰¹TI-labeled imaging in 108 patients. Teboroxime was injected first during exercise and then at rest. Nine myocardial segments per study were scored with respect to uptake of activity during stress and at rest (teboroxime) or after redistribution (²⁰¹TI). Perfusion was defined as normal, reversible, or fixed. Overall agreement of ²⁰¹TI versus teboroxime segmental perfusion (normal vs abnormal) was 772/961 (80.3%; \gc² = 258; p<0.001; κ=0.51) or (normal vs reversible vs fixed) 711/961 (74.0%; \gc² = 296; p<0.001; κ=0.42). Fifty-six patients also underwent selective coronary angiography. Stenoses greater than 50% of lumenal diameter were drawn on individualized coronary artery diagrams applied to polar plots of scintigraphic segments to compare detection of coronary artery disease. Sensitivity and accuracy of teboroxime were 0.80 and 0.79, respectively, compared with 0.84 and 0.82 for ²⁰¹TI (difference not significant). Mean imaging procedure time was 113.6 minutes for teboroxime and 240.5 minutes for ²⁰¹TI (p<0.001). Conclusions: ^99mTc-labeled teboroxime is amenable to simple modifications of routine treadmill exercise SPECT myocardial perfusion imaging protocols with widely available single-detector SPECT systems. This modality provides results similar to those of exercise ²⁰¹TI SPECT and is significantly faster.