Integral Parameter Analysis Using 4D Flow MRI Data for Carotid Artery Stenosis*

As cardiovascular and cerebrovascular diseases become more prevalent, the value of hemodynamic studies for predicting disease progression is increasingly recognized. These studies often use CFD and 4D-flow MRI to calculate critical parameters such as wall shear stress, oscillatory shear index, and relative residence time. However, these methods present challenges: CFD can yield inconsistent velocity information due to variable boundary conditions, while 4D-flow MRI suffers from low resolution, noise, and artifacts leading to inaccurate results, especially for differential parameters such as WSS and OSI. We propose a novel approach using integral hemodynamic parameters for more accurate disease analysis instead of relying solely on differential parameters. We prepared carotid artery phantoms and implemented patient-specific pulsatile flow to measure the phantom flows using 4D-flow MRI with relatively high spatial resolution. As a result, we computed integral hemodynamic parameters of stasis and recirculation and compared them against the conventional parameters of WSS, OSI, and RRT. Additionally, abnormal regions were redefined for the integral analysis, and the results were in good agreement with those obtained from the differential analysis. Our findings reveal that the integral analysis method demonstrates substantial alignment with the conventional approach, introducing a promising direction for enhanced, more reliable hemodynamic studies in carotid artery stenosis.