Knott KD, et al. - Given that cardiac MR stress perfusion is still a qualitative technique in clinical practice because of technical and postprocessing challenges, researchers examined the diagnostic performance of this technique in detecting occlusive coronary artery disease (CAD) in patients scheduled to have coronary angiography. Study participants were 50 patients with suspected CAD and 24 healthy volunteers. Investigators found that even in vessels with <50% stenosis, patients had lower stress myocardial blood flow (MBF) and myocardial perfusion reserve (MPR) vs volunteers. The results of this prospective, observational indicate that perfusion mapping is highly accurate for diagnosing occlusive CAD; high sensitivity and negative predictive value make it a potential "rule-out" test. The most accurate parameters were stress endocardial and transmyocardial MBF, but MPR was less accurate.