A Functional Region-Based Approach for the Numerical Simulation of Patient-Specific Cerebral Blood Flows With...

Area of Science:

• Medical Imaging
• Computational Fluid Dynamics
• Biomedical Engineering

Background:

• Accurate outflow boundary conditions are crucial for 3D computational fluid dynamics (CFD) simulations of patient-specific cerebral blood flow.
• Traditional Windkessel models often use simplified geometric factors, leading to inaccuracies due to medical image quality and vessel representation limitations.

Purpose of the Study:

• To introduce and validate a novel functional region-based approach for enhancing the accuracy of cerebral blood flow simulations.
• To improve the reliability of patient-specific CFD models by addressing limitations of conventional methods.

Main Methods:

• Cerebral vessels were segmented into functional regions by integrating population-based flow data with patient-specific arterial geometries from medical images.
• Windkessel model parameters for individual outlets were calculated within each region, considering both functional and geometric characteristics.
• Validation involved a single-subject case comparing the functional region-based approach against a conventional area-based method using Transcranial Doppler ultrasound data.

Main Results:

• The functional region-based approach showed superior alignment with clinical measurements compared to the area-based method.
• Velocity profiles were more accurate at 5 out of 7 monitored locations.
• Blood flow distribution agreement improved, with a maximum percentage difference of -4.5%.

Conclusions:

• Integrating vascular geometry and functional perfusion data offers a physiologically informed strategy for setting outlet boundary conditions in cerebral blood flow simulations.
• This approach has the potential to significantly improve the reliability of patient-specific simulations by mitigating errors from imaging artifacts and geometric simplifications.