Aortic strain, flow pattern and wall shear stress in a patient-specific compliant aorta replica using Shake-the-Box

Medical Engineering & Physics, vol. 135, pp. 104263

Abstract

• A low-cost, high-fidelity manufacture of a patient-specific compliant thoracic aorta. • Aortic flow measurements were carried out using the state-of-art Lagrangian particle tracking scheme – Shake-the-Box. • The velocity and wall shear stress at peak systole were in good agreement with in vivo MRI measurements. • The aortic distensibility and strain were estimated based on the flow measurements. • The relatively large lumen dimension change (42 %) in a cardiac cycle suggests the necessity of considering wall deformation in aortic flow studies. • Turbulent kinetic energy was calculated and visualized at peak systole. High-fidelity in vitro flow simulator in combination with high-dimensional flow visualization techniques can offer precise and comprehensive evaluation of aortic hemodynamics. However, it is particularly challenging to create a fully transparent aorta replica that faithfully mimics the aortic curvature and stiffness. In this study, we successfully manufactured a patient-specific compliant aorta phantom with a dilated ascending aorta that can be used in vitro hemodynamic study. We conducted pulsatile flow measurement on the deformable aorta replica using advanced 4D particle tracking velocimetry – Shake-the-Box. The aortic distensibility, circumferential strain, flow pattern, wall shear stress (WSS), and turbulent kinetic energy were assessed. Furthermore, the peak velocity field and WSS distribution were compared to in vivo MRI measurements. We found that the distensibility and circumferential strain of our aortic replica fell within the physiological range of young patients. The aortic diameter changed as much as 5.4 mm (42 %) in a cardiac cycle and the aortic distensibility was 9.9 × 10 –3 mmHg -1 . In addition, the obtained flow pattern and WSS distribution were found in a good agreement with in vivo MRI measurement. In conclusion, the compliant aorta phantom replicated the aortic wall material well. It also faithfully simulated the aortic flow and near-wall hemodynamics. The relatively large lumen dimension change (5.4 mm) in a cardiac cycle suggests the necessity of considering wall deformation in aortic flow simulations. We propose employing this approach for future studies, such as medical treatment training, validation of in silico fluid-structure interaction models, or as a complement to in vivo measurements.

Authors 5

1. Xiaolin Wu corresponding

   J.M. Burgerscentrum · Delft University of Technology

   Affiliation as printed

   Department of Chemical Engineering, Faculty of Applied Sciences, Delft University of Technology, Delft, the Netherlands; J. M. Burgerscentrum Research School for Fluid Mechanics, Delft, the Netherlands. Electronic address: X.Wu-5@tudelft.nl

2. Kaspar M. B. Jansen

   Delft University of Technology

   Affiliation as printed

   Department of Sustainable Design Engineering, Delft University of Technology, Delft, the Netherlands

3. Jos J.M. Westenberg Aachen Department of Radiology, Leiden University Medical Center

   Leiden University Medical Center

   Affiliation as printed

   Department of Radiology, Leiden University Medical Center, Leiden, the Netherlands

4. Hildo J. Lamb Aachen Department of Radiology, Leiden University Medical Center

   Leiden University Medical Center

   Affiliation as printed

   Department of Radiology, Leiden University Medical Center, Leiden, the Netherlands

5. Saša Kenjereš

   J.M. Burgerscentrum · Delft University of Technology

   Affiliation as printed

   Department of Chemical Engineering, Faculty of Applied Sciences, Delft University of Technology, Delft, the Netherlands; J. M. Burgerscentrum Research School for Fluid Mechanics, Delft, the Netherlands. Electronic address: S.Kenjeres@tudelft.nl