Ultrasound vibro-elastography for assessing water content in a lung sponge phantom model

Abstract

Pulmonary edema is common in patients with congestive heart failure. Extravascular lung water (EVLW) correlates to the disease prognosis but the assessment is challenging. The current standard method, computed tomography (CT), poses a significant logistic burden and exposes patents to ionizing radiation. Non-invasive lung ultrasound (LUS) is introduced to subjectively evaluate B-lines for EVLW but results in significant inter-observer variability. We have developed ultrasound vibro-elastography (USVE) to safely measure lung surface wave speed quantitatively. In this abstract, we presented the technique for analyzing water content in a lung phantom model. A sponge is used as the lung phantom. Twelve water contents were injected in the phantom for different EVLW values. The mass density of the phantom was measured for each water content. Wave propagation was generated at five frequencies between 100 Hz and 300 Hz in the phantom, and the surface wave speeds were collected. The viscoelasticity was derived from the wave speed dispersion with frequency. The obtained surface wave speeds showed no clear correlation with different water content. The elasticity and viscosity, however, were found increased with water content. This research pinpoints the likelihood and possible direction for USVE to assess EVLW for patients with pulmonary edema.