The frequency of ischemic stress/rest myocardial perfusion imaging (MPI) studies according to baseline coronary calcium scores among patients divided according to post-test likelihood (LKHD) of obstructive coronary artery disease (CAD), incorporating the results of age, gender, CAD risk factors, chest pain, and exercise ECG results. Both among patients with low and intermediate CAD likelihood, the frequency of ischemia was low for patients with CAC scores <400. By contrast, the CAC “threshold” for ischemia was substantially lower among patients with a high likelihood of CAD. Reproduced from Rozanski et al19, with permission of the publisher.©Springer 2007.