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The viscoelasticity of arterial walls is an important parameter to use when diagnosing cardiovascular disease. Recently, the index of arteriosclerosis has been clinically evaluated by looking at factors such as pulse transit time and ankle branchial pressure index. However, the indirect method does not reflect the actual real properties of arterial walls, which may lead to misdiagnosis. Therefore, just looking at pulse transit time is not a satisfactory parameter to evaluate arterial viscoelasticity. In this research, we used a Lamb wave velocity dispersion model to estimate the viscoelastic material properties of arterial phantoms. The arterial walls were composed of a thin layer plate merged in a water fluid in which the vibrations are induced by an external vibrator excitation such as a Lamb wave. A mechanical actuator was used to create a repetitive 50Hz to 200Hz low-frequency air-puff excitation to excite the harmonic mechanical waves in the latex pipe wall. The velocity of the traveling waves was measured by a fiber-based laser doppler vibrometer. The laser doppler vibrometer was the incorporation of a circulator which allowed for uni-directional transmission of electromagnetic waves, so that only the probe could achieve the purpose of emitting and receiving light. Moreover, the system was mounted on a linear translation stage and the traveling waves velocity were measured at multiple points. Then, the wave velocities were calculated by calculating the signal phase difference between the different measured positions. The viscoelastic property of the latex pipe was used to calculate the Lamb wave velocity by using a Lamb wave dispersion model. In conclusion, we propose a novel method to measure the viscoelastic properties of arterial walls in-vitro with high accuracy. Simulated experiments were performed to validate the proposed method. Our new proposed method has the potential to more accurately diagnose cardiovascular diseases for both home health care and for clinical medicine.
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