Shifting gears from oncology, there are 2 FDA-approved PET tracers for myocardial perfusion PET, 82-rubidium chloride and 13-N-ammonia. Resting images and stress images are obtained and the 2 sets of images are compared for perfusion defects. Matched defects indicate infarct, and mismatched defects (seen on stress only) indicate ischemia. The myocardium can be stressed by adenosine, regadenoson, dipyridamole, or dobutamine (cannot do exercise stress with PET agents). Myocardial perfusion PET also quantifies coronary flow reserve (CFR), or the ratio of stress flow to rest flow.
Case depicts a myocardial perfusion PET performed with Rb-82. Top row shows the stress images with a perfusion defect in the inferolateral wall (yellow arrows) that is not seen at rest (middle row). CFR was abnormal throughout the myocardium, most severe in the inferolateral wall (red arrow). The patient was referred for cardiac catheterization; left circumflex artery stent was placed and ischemia resolved at repeat PET (images not shown). Case courtesy of Dr. Thomas Anderson.