Comparisons of Morphological Measurement Between Coronary Computed Tomography and Optical Coherence Tomography

The objective of this study is to evaluate the precision of semi-automated lumen boundary identification from coronary computed tomography angiography (cCTA) by current version of HeartFlow software and the impact on fractional flow reserve (FFRCT) by using optical coherence tomography (OCT) as reference standard.

Analysis of cCTA and OCT was conducted under blind in independent organizations.

After unblinding the cCTA and OCT case identification number, the OCT image was co-registered to cCTA data.

After co-registration of cCTA and OCT lesion locations, the minimal lumen area (MLA) was detected with both modalities. FFROCT was calculated using OCT-updated models in which cCTA-based lumen geometry was replaced by OCT-based lumen geometry.

Lesions were grouped according to their severity of calcification (using Agatston score) and minimum lumen diameter.

Inclusion Criteria:

- Patients who underwent cCTA prior to coronary angiography and OCT within 6 months.

Exclusion Criteria:

1. Prior coronary artery bypass graft (CABG) surgery
2. Contraindication to beta blocker agents or nitrates
3. Tachycardia or significant arrhythmia
4. Impaired chronic renal function (eGFR <30)
5. Subjects with known anaphylactic allergy to iodinated contrast material
6. Pregnancy or unknown pregnancy status in subject of childbearing potential
7. Cases with poor OCT or CCTA image for analyzing