Flow phantom for contrast enhanced ultrasound research, device validation, and clinical training

Abstract

Phantoms are an important part of ultrasound research, instrument development, and clinical training. There are, however, no standardized phantoms for contrast enhanced ultrasound. Phantoms typically include either tubes to mimic flow in larger vessels or dialysis tubing to mimic perfusion in the capillary bed. These approaches fail to mimic the full range of flow regimes and tissue scattering observed in the body during imaging. To address some of these limitations, we designed a phantom that integrates flow in both the macro- and microcirculation with physiological tissue backscatter, attenuation, and sound speed and that can be customized to simultaneously mimic flow in normal and malignant tissues. A variety of sponges and foams were considered. Acceptable materials were fit in a custom-built flow chamber and imaged with a commercially available ultrasound system. A polyvinyl alcohol (PVA) sponge was deemed to be a suitable phantom material. PVA has a sound speed of 1490 m/s and attenuation coefficient of 0.6 dB/cm/MHz. After introducing a contrast agent into the flow system, the agent could be visualized rapidly entering the flow inlets, perfusing slowly through the sponge, and rapidly exiting through the flow outlets. [Funded by Philips Ultrasound and the Life Sciences Discovery Fund No. 3292512.]Phantoms are an important part of ultrasound research, instrument development, and clinical training. There are, however, no standardized phantoms for contrast enhanced ultrasound. Phantoms typically include either tubes to mimic flow in larger vessels or dialysis tubing to mimic perfusion in the capillary bed. These approaches fail to mimic the full range of flow regimes and tissue scattering observed in the body during imaging. To address some of these limitations, we designed a phantom that integrates flow in both the macro- and microcirculation with physiological tissue backscatter, attenuation, and sound speed and that can be customized to simultaneously mimic flow in normal and malignant tissues. A variety of sponges and foams were considered. Acceptable materials were fit in a custom-built flow chamber and imaged with a commercially available ultrasound system. A polyvinyl alcohol (PVA) sponge was deemed to be a suitable phantom material. PVA has a sound speed of 1490 m/s and attenuation coefficien...