Assessment of extracranial carotid artery disease using digital twins - A pilot study

Area of Science:

• Biomedical Engineering
• Medical Imaging
• Fluid Dynamics

Background:

• Accurate risk stratification is crucial for patients with extracranial internal carotid artery disease (CAD).
• Fractional flow reserve (FFR) is a gold standard in coronary artery disease, but noninvasive methods are needed for carotid arteries.
• Computational fluid dynamics (CFD) offers a potential noninvasive approach for functional assessment.

Purpose of the Study:

• To develop and validate a CFD-based workflow for noninvasive functional assessment of extracranial internal carotid artery disease (CAD).
• To utilize patient-specific digital twins derived from computed tomography angiography (CTA).
• To establish a foundation for CFD-derived metrics analogous to FFR in carotid artery disease.

Main Methods:

• Reconstruction of 37 patient-specific digital twins of carotid bifurcations from CTA data.
• Implementation of a CFD model with Doppler ultrasound (DUS) peak systolic velocity (PSV) as inlet and Windkessel model as outlet boundary conditions.
• Comparison of CFD-derived PSV with DUS measurements in the internal carotid artery (ICA).

Main Results:

• A relative error of 9% ± 20% and an intraclass correlation coefficient of 0.88 were found between DUS and CFD for PSV.
• Hyperemic CFD simulations demonstrated significant differences in pressure drops across stenoses with similar anatomical narrowing.
• The method successfully identified varying hemodynamic significance in stenoses.

Conclusions:

• A validated CFD workflow using digital twins enables noninvasive functional assessment of internal carotid artery disease (CAD).
• This approach provides a basis for developing noninvasive hemodynamic indices similar to FFR for carotid artery stenosis.
• The findings support improved risk stratification and patient selection for revascularization procedures.