MR-based wall shear stress measurements in fully developed turbulent flow using the Clauser plot method.

Area of Science:

• Biomedical Engineering
• Fluid Dynamics
• Medical Imaging

Background:

• Wall shear stress (WSS) quantifies blood flow friction on vessel walls and is a potential biomarker for cardiovascular diseases.
• Phase-contrast (PC) Magnetic Resonance (MR) imaging allows direct estimation of WSS from velocity measurements.

Purpose of the Study:

• To investigate the Clauser plot method for estimating WSS in fully developed turbulent stationary flow using PC-MR velocity measurements.
• To evaluate the accuracy and resolution-independence of the Clauser plot method for WSS quantification.

Main Methods:

• The Clauser plot method was applied to 2D PC-MR phantom measurements at 3T across various Reynolds numbers and in-plane resolutions.
• WSS values were compared against Laser Doppler Velocimetry (LDV) measurements and theoretical friction factor calculations.
• MR-based WSS quantification was also performed using an in-house software tool for comparison.

Main Results:

• Clauser plot derived WSS values showed good agreement with LDV and theoretical results (∼5% deviation) across all tested Reynolds numbers.
• Clauser plot results were largely independent of spatial resolution, unlike the in-house software which showed >100% deviations.
• The method demonstrated high consistency in WSS estimation for fully developed turbulent flow.

Conclusions:

• The Clauser plot method is a valuable, resolution-independent approach for MR-based WSS estimation in controllable turbulent flow settings.
• It can serve as a validation tool for MR-based WSS quantification algorithms before clinical application, despite limitations in direct in vivo use.