This study will evaluate the level of agreement between noninvasive CCTA (coronary computed tomography angiography)-based quantification and characterization of coronary atherosclerosis and invasive IVUS (intravascular ultrasound).

This is a prospective, multi-center study. All patients who have a stenosis in at least one major epicardial vessel confirmed by CCTA, who have undergone FFRCT (Fractional flow reserve-computed tomography) analysis, and who are scheduled to undergo clinically indicated IVUS-guided invasive evaluation and/or treatment will be eligible for enrollment. Enrolling sites will have FFRCT analysis incorporated when indicated into their standard evaluation of CCTA scans. Data collected will include CCTA and FFRCT, full angiographic, and IVUS images, and if obtained, any other imaging or physiologic data including OCT (Optical coherence tomography), FFR (fractional flow reserve), any NHPR (non-hyperemic pressure ratios) (e.g., dPR (diastolic pressure ratio), RFR (resting full-cycle ratio), iFR (instantaneous wave-free ratio), etc.), and pre- and post-stent implantation invasive data. All non-invasive and invasive data collected will be obtained as clinical practice consistent with standard clinical care.

Inclusion criteria (all must be present):

1. Age ≥18 years
2. Clinically stable patient with known CAD
3. CCTA showing stenosis in at least one major epicardial vessel of stentable/graftable diameter, in whom clinically indicated IVUS is planned within 45 days of the CCTA and FFRct available
4. FFRct successfully processed
5. Willing to comply with all aspects of the protocol
6. Agrees to be included in the study and able to provide written informed consent.

Exclusion criteria (all must be absent):

1. 1. CCTA showing no stenosis
2. Uninterpretable CCTA by HeartFlow assessment, in which image quality prevents FFRCT from being processed.
3. Acute chest pain
4. CABG (coronary artery bypass graft) prior to CCTA acquisition
5. Prior history of PCI for 3 or more vessels
6. MI (myocardial infarction) less than 30 days prior to CCTA or between CCTA and ICA.
7. Suspicion of acute coronary syndrome (acute myocardial infarction or unstable angina)
8. Known complex congenital heart disease
9. Tachycardia or significant arrhythmia
10. Subject requires an emergent procedure
11. Evidence of ongoing or active clinical instability, including acute chest pain (sudden onset), cardiogenic shock, unstable blood pressure with systolic blood pressure <90 mmHg, and severe congestive heart failure (NYHA [New York Heart Association] III or IV) or acute pulmonary edema
12. Any active, serious, life-threatening disease with a life expectancy of less than 2 months
13. Currently enrolled in another study utilizing FFRCT or in an investigational trial that involves a non-approved cardiac drug or device
14. Persons under the protection of justice, guardianship, or curatorship

Clinically stable patients with known CAD who have a CCTA showing stenosis in at least one major epicardial vessel of stentable/graftable diameter and in whom clinically-indicated IVUS is planned.

Baseline participants is not the same as the Participant flow as 21 participants were excluded from analysis due to technical limitations and we were not able to process medical imaging data.

No adverse event data was collected. This was an observational study and all patients received standard clinical care, no intervention was given.

No adverse event data was collected. This was an observational study and all patients received standard clinical care, no intervention was given. The total number of participants at risk is "0" because there was no adverse event data collected.