A Pilot Study of Wet Lung Using Lung Ultrasound Surface Wave Elastography in an Ex Vivo Swine Lung Model

Abstract

Extravascular lung water (EVLW) is a basic symptom of congestive heart failure and other conditions. Computed tomography (CT) is standard method used to assess EVLW, but it requires ionizing radiation and radiology facilities. Lung ultrasound reverberation artifacts called B-lines have been used to assess EVLW. However, analysis of B-line artifacts depends on expert interpretation and is subjective. Lung ultrasound surface wave elastography (LUSWE) was developed to measure lung surface wave speed. This pilot study aimed at measureing lung surface wave speed due to lung water in an ex vivo swine lung model. The surface wave speeds of a fresh ex vivo swine lung were measured at 100 Hz, 200 Hz, 300 Hz, and 400 Hz. An amount of water was then filled into the lung through its trachea. Ultrasound imaging was used to guide the water filling until significant changes were visible on the imaging. The lung surface wave speeds were measured again. It was found that the lung surface wave speed increases with frequency and decreases with water volume. These findings are confirmed by experimental results on an additional ex vivo swine lung sample.

Ultrasound Elastography for Lung Disease Assessment

“…Water was injected into the lung through the trachea. The surface wave propagation was generated using a small vibrator and measured using an ultrasound probe (adapted from [53]). a variety of chemical or mechanical means, after complete drainage of the effusion that allows parietal-to-visceral pleural apposition.…”

“…Zhang et al [53], [54] performed LUSWE on an ex vivo porcine lung model to assess the effects of pulmonary edema on the mechanical properties of lung tissue. Various amounts (0, 120, and 240 mL) of water were poured into the lung through the trachea with ultrasound imaging used to guide the water filling until the water overflowed the lung surface (Fig.…”