A finite element viscoelastic model based on consecutive transverse ultrasound images of carotid artery

In the present study, a finite element model has been presented using both the in-vivo geometry of a healthy man carotid artery, which was extracted from consecutive transverse ultrasound images and the pulse pressure waveform and Kelvin viscoelastic model parameters that were obtained from processing the consecutive longitudinal ultrasound images. Extracting the internal diameter waveform from longitudinal ultrasonic image processing and calibrating it via an exponential equation, blood pressure waveform of the carotid artery was extracted. A Gaussian function was fitted to the blood pressure waveform. Differentiating the fitted Gaussian equation resulted in the pressure differentiation of the carotid artery over the cardiac cycle. Kelvin viscoelastic parameters were estimated using an optimization method. Finite element model of the carotid artery was reconstructed in ADINA software and implemented by loading over three cardiac cycles. To validate the model, radial displacement waveform resulted from finite element model and that resulted from image processing were compares in nearly the same spatial position. Percentage of the mean proportional differences between the radial displacement resulted from finite element model and that from consecutive ultrasound images was 9.3. Since the appropriate mechanical models can calculate true stress/strain distribution of the carotid artry wall and plaque and distinguish the location of the plaque areas prone to vulnireability; and because of the capability of the ultrasonic model proposed in this study for describing the pulsatile behavior of artery wall accurately, it is expected that the introduced dynamic model to be applied for accurate evaluation of the arterial disease.