Assessing the Functional Severity of Carotid Artery Stenosis Using an Image-Based Hemodynamic Modeling Method

The distal-to-proximal pressure ratio (dpPR) has emerged as a superior indicator compared to the diameter stenosis rate (DSR) for assessing the functional severity of carotid artery stenosis (CAS). However, unlike DSR, dpPR cannot be directly determined by vascular imaging. In this study, we developed a hemodynamic modeling method to predict dpPR based on medical images available in clinical settings.

A multiscale modeling method was employed to integrate a three-dimensional (3D) hemodynamic model of CAS into a lumped-parameter model of systemic hemodynamics, while incorporating patient-specific geometric information of large cerebral arteries derived from computed tomography angiography (CTA) images. The 3D modeling method was validated through in vitro fluid dynamics experiments, while the accuracy of the resulting multiscale model in predicting dpPR was evaluated by comparing model predictions with invasive pressure wire measurements.

The model-predicted dpPR values for 27 carotid artery stenoses demonstrated strong agreement with invasive measurements, with a mean relative error of - 0.8% and a standard deviation of 2.5%. dpPR was only moderately correlated with DSR (r = - 0.55, p = 0.003). Further analysis revealed that the anatomical structure of the circle of Willis (CoW) is a major factor influencing the relationship between dpPR and DSR.

Constructing a multiscale model based on CTA images provides a practical approach for assessing the hemodynamic impact of CAS. The significant influence of CoW's anatomical structure on the relationship between dpPR and DSR underscores the importance of considering systemic cerebral hemodynamics when evaluating the functional severity of CAS.