Decreased [99mTc]Sestamibi uptake with dobutamine versus dipyridamole stress

Aim. Animal studies suggest an interference of dobutamine on [ ^99mTc]sestamibi uptake. In this study dobutamine was compared to dipyridamole rest-stress [^99mTc]sestamibi uptake ratio (UR). Methods. Twenty-five patients with suspect coronary artery disease (CAD) underwent rest, dobutamine, and dipyridamole [^99mTc]sestamibi SPECT at 24-h intervals and coronary angiography. UR was calculated separately for each coronary territory considering injected dose and acquisition delay. Results. There were 38 CAD territories in 20 patients. On a patient basis, dipyridamole SPECT sensitivity was 85%, versus 70% for dobutamine. On a territory basis, sensitivity was 66% versus 42% (P99mTc]sestamibi uptake underestimates the blood flow heterogeneity induced by dobutamine more than that produced by dipyridamole.