Does a shortened hyperemia with regadenoson stress pose a concern for quantitative Rb-82 PET imaging? Optimization of regadenoson PET imaging.

A lthough regadenoson has nearly replaced other vasodilator stressors for single-photon emission computed tomography perfusion imaging, the benefits of regadenoson stress for positron emission tomography (PET) perfusion are less clearly established, particularly in the estimation of absolute stress flow with dynamic PET imaging. In the estimation of absolute flow with dynamic PET, the timing of radiotracer administration needs to be carefully matched to the time and duration of coronary hyperemia. In this issue of iJACC, Johnson and Gould (1) suggest the regadenoson stress Rb-82 may underestimate flow that can be achieved with dipyridamole stress, and this underestimation is critically dependent on the timing of Rb-82 administration relative to the administration of regadenoson.