The device involved in this trail is a diagnostic software with a Prospective, Multicenter, Self Controlled design. FFRCT diagnostic performance was calculated by CardioSimFFRct Analysis software, and the diagnostic accuracy, sensitivity, specificity, positive predictive value and negative predictive performance of FFRCT for myocardial ischemia were calculated per-patient level and per-vessel level with invasive FFR value as gold standard.

The present study is a single arm, open label, prospective trial. Measurement of FFR during invasive cardiac catheterization represents the "gold standard" for assessment of the hemodynamic significance of coronary artery lesions. As we know, the major disadvantage of FFR is that it has to be measured invasively. CardioSimFFRct Analysis software is a non-invasive method to determine FFR which computes the hemodynamic significance of Coronary Artery Disease (FFRCT) from coronary computed tomography angiography（CCTA）data of the subject by using computational fluid dynamics.The FFR derived from FFR-CT will be compared with invasive FFR as gold standard.Moreover CardioSimFFRct also simplifies the coronary artery into a one-dimensional piping model, omits grid engineering, and greatly reduces the complexity of pretreatment.Based on the pressure loss along the pipe flow and the local pressure loss, a fast method for FFR calculation in engineering is proposed. The calculation time can be reduced to several minutes.

FFRct from CardioSimFFRct Analysis software is mainly based on CCTA images to image the coronary arteries. Through three-dimensional reconstruction of the coronary arteries and computational fluid Dynamics (CFD) technology, the simulation of blood flow in the blood vessels is realized to extract the coronary blood flow reserve score (FFR).FFRct has the following characteristics such as the FFR value can be measured noninvasively, without additional damage to patients, avoiding the risks brought by invasive surgery, and the side effects brought by drugs during invasive surgery.FFRct can realize the examination quickly, save the time of doctors' coronary functional assessment, and simplify the process of coronary functional assessment.It also has the function of three-dimensional reconstruction of blood vessels, which makes it convenient for users to view the whole structure of coronary arteries and make artificial correction.The results of FFRct have high repeatability and are easy for users to evaluate.

Inclusion Criteria:

Subjects that participate in this study must fulfill all the following criteria:

General inclusion criteria:

• Age ≥18 years and ≤ 80 years;
• Subject providing written informed consent;
• After the researcher assessed the suspected presence of coronary artery stenosis, coronary angiography and CCTA examination were proposed.

Angiographic inclusion criteria:

• CCTA inspection should be performed on instruments with at least 64 multidetector rows;
• CCTA images are clear and readable;
• The diameter of coronary artery lesion stenosis was measured by CCTA image with 30%-90%;
• The reference vessel diameter of coronary stenosis was ≥2.5mm by CCTA imaging.

Exclusion Criteria:

If subjects fulfill any of below criteria, this subject shall be exclude from this study.

General exclusion criteria:

• Pregnant and breast-feeding women;
• Previous ST-segment elevation myocardial infarction 30 days before CCTA examination, and a history of non-ST-segment elevation myocardial infarction 7 days before CCTA examination;
• Prior Coronary Artery Bypass Graft（CABG）,Pacemaker, Implantable Cardioverter Defibrillator（ICD）, Artificial Valve Implantation;
• Hypertrophic obstructive cardiomyopathy;
• Heart failure(NYHA≥III or Left Ventricular Ejection Fraction（LVEF）< 40%);
• Atrial fibrillation, supraventricular tachycardia, ventricular tachycardia and other arrhythmias;
• Body mass index >35kg/m2;
• Serum creatinine >178µmol/L or 2mg/dl;
• Allergies or contraindications to contrast agents are known;
• Subject who received Nicorandil within 2 weeks prior to invasive FFR examination;
• Any other conditions that are not suitable for the study.

Angiographic exclusion criteria:

• The quality of CT imaging is not good enough to extract coronary blood vessel trees;
• Visual measurement of coronary lesion diameter stenosis > 90% by CCTA imaging;
• The target lesions were diffuse lesions, and the lesion length was ≥ 30mm (visual measurement);
• There were ≥ 2 stenosis lesions in the target vessel;
• Stent implantation in the target vessel;
• Lesions involving aneurysms or myocardial Bridges;
• The target vessel is very tortuous and it is difficult to predict the passage of the pressure guide wire.
• Left main disease;
• Patients with acute coronary syndrome after CCTA examination and before invasive FFR examination;
• Severe calcification(i.e Diffuse calcification ,Local or segmental calcification)