Inclusion Criteria:  Patients' age ≥18 years; Has coronary CTA images acquired by ≥64 multidetector row CT scanner, no earlier than 2016 and within 60 days of the ICA-FFR procedure; Coronary CTA image shows at least one vessel segment (≥2mm diameter) with a diameter stenosis of 30%-90%;  Exclusion Criteria:  Patients with any of the following conditions at the time of CTA imaging:  Acute myocardial infarction; Unstable angina; Pulmonary edema; Heart function classification level III and IV (NYHA heart function classification); Implantable cardioverter defibrillator (ICD); Prior percutaneous coronary intervention (PCI) or pacemaker surgery; Prior coronary artery bypass grafting (CABG) surgery; Prior heart valve replacement; Prior history of complex congenital heart disease; Prior history of cardiomyopathy; BMI >35; Coronary total occlusion.