Dynamic CT Perfusion for Functional Assessment of Coronary Artery Disease

1. Subject Inclusion Criteria Patients need to meet all the following inclusion criteria to be enrolled in the study: 1. Symptomatic and hemodynamically stable 2. Acute coronary syndrome (ACS) ruled out based on absence of abnormal changes in ECG and cardiac enzymes 3. Referral for cardiac catheterization based on clinical history and non-invasive imaging test findings. Non-invasive imaging findings include one or more of the following: (i) Evidence of myocardial ischemia from radionuclide myocardial perfusion imaging; (ii) Evidence of myocardial ischemia from CMR myocardial perfusion imaging; (iii) Evidence of ≥ 50% stenosis in the left circumflex artery (LCx), left anterior descending artery (LAD) and/or right coronary artery (RCA) from CCTA. 4. Ability to undergo stress myocardial perfusion test (absence of contraindications for vasodilator) 5. Written informed consent 2. Subject Exclusion Criteria Patients meeting at least one of the following criteria will be excluded from the study: 1. Recent (\< 1 month) ACS 2. CCTA reveals ≥ 50% stenosis in the left main artery 3. Severe chronic kidney disease (CKD) with estimated glomerular filtration rate (eGFR) \< 30 mL/min/1.73m2 4. Contraindications to stress perfusion imaging, including: i) severe reactive airway disease; ii) high-grade atrioventricular block; iii) allergy to vasodilators; iv) caffeine within 12 hours; v) theophylline use within 48 hours. 5. History of CABG surgery 6. History of malignancy during the past 3 years prior to screening 7. History of alcohol and/or drug abuse within 3 years prior to screening 8. Sign of pregnancy 9. Pregnant or nursing 10. History of severe allergic or anaphylactic reaction to any allergen including drugs and contrast agents 11. Recent (\< 1 month) use of an investigational drug or device 12. Participation in any other investigational drug or device trial during the conduct of this study 13. Lack of ability or willingness to comply with the protocol requirements or deemed by the Site Investigator to be unfit for the study