Functional Assessment of Coronary Artery Disease by CTA Flow Encoding

The purpose of this pilot study is to test the ability of Transluminal Flow Encoding (TAFE) to evaluate vessel specific ischemia in patients with a clinical indication for invasive coronary angiography (ICA) with fractional flow reserve (FFR) measurements for suspected coronary disease. TAFE is a novel method that derives coronary blood flow from easily obtainable non-invasive coronary CT angiograms. Participants will undergo a rest coronary CTA, a regadenoson stress CT, and a clinically indicated invasive coronary angiogram. The study aims to determine the accuracy of TAFE compared to invasive fractional flow reserve. We hypothesize that TAFE-derived coronary blood flow, coronary flow reserve, and myocardial CT perfusion imaging can accurately diagnose an abnormal FFR (\<0.80) measured in vessels in patients undergoing invasive coronary angiography.