The objective of this multicenter study is to evaluate the diagnostic accuracy of dynamic cardiac CT perfusion (CTP) imaging for non-invasive functional assessment of coronary artery disease (CAD). The proposed CTP technique allows concomitant assessment of two imaging-derived cardiac biomarkers including fractional flow reserve (FFR) and myocardial perfusion from a single dynamic imaging sequence, which facilities simultaneous evaluation of the hemodynamics in epicardial coronary arteries and coronary microcirculation in patients with CAD. The CTP results will be compared with invasive coronary angiography / FFR assessment and non-invasive cardiac magnetic resonance imaging (CMR) / radionuclide perfusion assessment.

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

Eligible patients are those who have clinically indicated referral for cardiac catheterization based on clinical history and sign of ischemia or obstructive coronary lesion(s) from non-invasive imaging test (radionuclide myocardial perfusion imaging, CMR myocardial perfusion imaging, or CCTA).