Coronary computed tomography angiography (CTA) is well known to have high sensitivity and negative predictive value to rule out anatomic coronary artery disease, but can have a relatively low specificity to detect obstructive coronary disease and ischemia (1). Accurate predictions of physiologic myocardial blood flow determined on the basis of anatomic coronary artery stenosis, be it from coronary CTA or from invasive coronary angiography, have been in a quandary for decades. Numerous previous studies have shown only an average correlation between angiographic stenosis and measures of ischemia such as myocardial perfusion imaging (MPI) assessments with positron emission tomography (PET), cardiac magnetic resonance (CMR), or invasive fractional flow reserve (FFR) 2, 3, 4. Despite this finding, angiographic stenosis evaluation remains the most common decision point for whether a patient receives further study or treatment. Thus, contrast dye does not lie with regard to the presence of coronary stenosis, but it is then challenged to identify myocardial ischemia.