Head-to-head comparison between technetium-99m-sestamibi and thallium-201 tomographic imaging for the detection of coronary artery disease using combined dipyridamole-exercise stress

Aim: The purpose of this study was a head-to-head comparison of tomographic imaging (SPECT) with technetium-99m (Tc-99m)-sestamibi and thallium-201 (TI-201) using dipyridamole-low-level bicycle exercise stress for the assessment of coronary artery disease. Methods: We studied 38 consecutive patients referred for the evaluation of chest pain who had undergone coronary angiography. The patients were randomly allocated to Tc- 99m-sestamibi SPECT followed by TI-201 SPECT or vice versa. The accuracy of both tracers in detecting significant coronary artery disease (>50% luminal stenosis) was 87% (95% confidence interval 72-96%). Only two patients were classified differently by the two methods. Results: On a segmental basis, good agreement was found between Tc-99m-sestamibi and TI-201 for both the localization and the nature of perfusion defects (reversible or persistent) identified (Cohen's kappa = 0.67). Conclusion: No clinically relevant differences in diagnostic accuracy were demonstrated between Tc-99m-sestamibi and TI-201 SPECT using combined dipyridamole-exercise stress for the evaluation of coronary artery disease.