Nils P. Johnson, and K. Lance Gould JIMG 2011;4:990-998 Examples of Clinical Categories of Patients Although quantitative data were obtained for all quadrants, the positron emission tomography (PET) images show only the significant single view for publication efficiency. (A) Definite ischemia. Rest–dipyridamole PET shows a severe, inferior, stress-induced perfusion defect with lowest stress flow of 0.3 ml/min/g and coronary flow reserve (CFR) of 0.6, indicating myocardial steal associated with collaterals to an occluded, dominant left circumflex coronary artery. In the basal inferior area, vasodilator stress flow of 2.1 ml/min/g and CFR of 3.9 are excellent. (B) No ischemia with dense coronary calcifications, a coronary arteriogram reportedly showing moderate 3-vessel disease for which bypass surgery was recommended, leading to PET for a second opinion. Rest–dipyridamole PET shows no clinically significant stress-induced perfusion defect with high stress perfusion of 3.4 ml/min/g and CFR of 4.1, indicating excellent flow capacity with diffuse, calcific, nonobstructive coronary atherosclerosis and no flow-limiting stenosis. (C) Indeterminate clinical features. Rest–dipyridamole PET shows a moderate, anterior, stress-induced perfusion defect in the distribution of a diagonal but with adequate stress perfusion of 1.6 ml/min/g and adequate CFR of 2.9 in the defect. Nils P. Johnson, and K. Lance Gould JIMG 2011;4:990-998 American College of Cardiology Foundation