Characterizing the viscoelastic properties of a tissue mimicking phantom for ultrasound elasticity imaging studies

With the increased use of ultrasound (US) imaging in biomedical fields, the ability to provide phantoms that are capable of mimicking desired properties of soft tissues is important. Polyvinyl alcohol (PVA) is a polymer of great interest because of its relatively simple chemical structure, ease of processing, and satisfactory acoustic and durability properties. PVA may be useful as a phantom material in the study of ultrasound elasticity imaging (UEI) for liver fibrosis. A PVA-based US phantom was constructed through a freeze–thaw process, and measurements of mechanical properties of PVA were carried out with a rotational rheometer. The storage modulus and the loss modulus of PVA were obtained, and the elasticity and viscosity of PVA phantom were estimated by using Voigt viscoelastic model. The obtained viscoelastic results were compared with those of liver at fibrosis stage. Our study suggests that it is possible to construct a PVA based phantom that mimics fibrous liver for the purpose of UEI imaging studies.