Inclusion Criteria:  Patients undergoing invasive coronary angiography because of abnormalities found on CCTA in either the left or right coronary artery and no or minimal stenosis (CAD-RADS 0-1; 0-24% stenosis) in the contralateral coronary artery within 90 days.  Exclusion Criteria:  Refusal of informed consent Abnormalities in both coronary arteries on CCTA Prior PCI Prior coronary artery bypass grafting (CABG) Major allergy to iodinated contrast agent Inability to provide informed consent, and/or known pregnancy.