Impact of cardiac phase selection on computational fluid dynamics analysis.

Area of Science:

• Cardiovascular Imaging
• Biomedical Engineering
• Computational Fluid Dynamics

Background:

• Cardiac phase selection in coronary computed tomography angiography (CCTA) can influence computational fluid dynamics (CFD)-derived hemodynamic metrics.
• This influence is not well-quantified, particularly in patients with anomalous coronary arteries.

Purpose of the Study:

• To evaluate the impact of cardiac phase selection on CFD outcomes in both normal and anomalous coronary arteries.
• To quantify phase-dependency of hemodynamic metrics in different coronary anatomies.

Main Methods:

• Analysis of multiphase CCTA datasets from 40 patients (including normal, anomalous right coronary artery [ARCA], and myocardial bridging [MB] anatomies).
• Calculation of CFD-derived parameters: time-averaged wall shear stress (TAWSS), oscillatory shear index (OSI), relative residence time (RRT), and CCTA-derived fractional flow reserve (CT-FFR).
• Assessment of phase-dependency by comparing measurements across different cardiac phases and patient groups.

Main Results:

• Luminal area differences showed significant group-distance interactions across phases.
• Oscillatory shear index (OSI) differences were smaller in myocardial bridging (MB) patients compared to normal controls.
• While TAWSS, OSI, and RRT exhibited phase-dependency, CCTA-derived fractional flow reserve (CT-FFR) showed lower variation, with no significant differences observed for any parameter relative to zero.

Conclusions:

• Coronary geometry demonstrates clear phase-dependency, impacting hemodynamic analysis.
• The phase-dependency of TAWSS, OSI, and RRT necessitates careful consideration during CCTA-based CFD analysis.
• Standardizing cardiac phase selection is essential for enhancing the accuracy and clinical consistency of CCTA-derived CFD results.