P2.06 A NOVEL INFLATION TEST TECHNIQUE AND OPTICAL FLOW ESTIMATION FOR IN VITRO DETERMINATION OF THE CROSS-SECTIONAL DEFORMATION OF ARTERY

Abstract

Objectives: Determination of the cross-sectional mechanical properties of artery is crucial for correlating regional arterial stiffness with the biological components such as collagen, elastin, and deposited calcium. While ultrasound imaging has been used to determine these properties from the arterial deformation, the accuracy of the measurements is limited due to non-direct imaging on the arterial cross-section. Therefore, we designed a novel inflation test technique allowing this direct imaging. Methods: The test system provides internal pressures to an artery ring using a pump connected to a pressure transducer and a balloon tube (Figure 1). The cross-sectional deformation of the artery is captured using a camera. The images are then analysed using optical flow estimation which determines the deformations from pixel motions. This optical flow technique has been validated with images of a ring structure undergoing known deformations. Results: This test system has been tested with pig aortas. The regional strains of an aortic ring sample are shown in Figure 2. Conclusions: This inflation test design and the optical flow estimation allow in vitro determination of arterial regional strains at physiological pressures. A finite element model will be developed to correlate the deformations between the experiments and models to determine the regional mechanical properties of the artery. This approach will be used to investigate the associations of ageing-induced arterial stiffening with regional structural changes such as calcium deposition and elastin fragmentation, promoting the determination of target biological components for drugs. Figure 1Inflation test system. Figure 2Calculated arterial strains.