Simulation-based Parameter Estimation using a viscoelastic Material Model on artificial Vocal Folds to validate Ultrasound Elastography

The material properties of the vocal folds play an important role in phonation, but are also of interest for basic research. In the diagnosis of e.g. vocal fold palsy ultrasound is still an emerging technology. Ultrasound elastography, a technique measuring the tissue stiffness, is widely employed in the diagnosis of e.g. liver fibrosis and thyroid nodules. Using a quasi-static approach, this technique can also be applied to the vocal folds, improving the understanding of their biomechanical properties and, in the future, the diagnosis of pathological changes in the vocal folds. We use a gelatin phantom of the vocal folds, modeled after the well-known M5 model of the true vocal folds and augmented with additional material that mimics the surrounding tissue. The phantom is compressed with an ultrasound transducer in the inferior direction, with the image plane in the frontal plane. Ultrasound images of the compression process and the acting force are recorded. Based on this information, a developed elastography algorithm evaluates the data. The results of the experimental setup are compared with simulation results generated using FEBio, a software specialized in tissue simulation.