Citations

Zebrafish are being increasingly used as animal models for human diseases such as cardiomyopathy and neuroblastoma because zebrafish have a nearly fully sequenced genome to humans. One pilot study is to develop zebrafish echocardiography. Because the heart of a zebrafish is small, a high frequency ultrasound system (50–80 MHz) is used for imaging. B-Mode imaging is analyzed for quantification of ejection fraction (EF), end-systolic volume (ESV), and end-diastolic volume (EDV). Pulse-wave Doppler (PWD) is used to calculate the E/A ratio (the peak velocities of E and A waves) and myocardial performance index (MPI). Techniques for improving image quality and repeatability of zebrafish echocardiography are discussed. Another pilot study is to develop zebrafish ultrasound vibro-elastography (ZUVE) for measuring the elastic properties of zebrafish. An adult female zebrafish is anesthetized for 3 min. A 0.1-s gentle harmonic vibration is generated on the tail of a zebrafish using a sphere tip indenter with a 3 mm diameter. Shear wave propagation in the zebrafish is measured using a high frequency 18 MHz ultrasound linear array probe. We conclude that ZUVE is safe, fast, and noninvasive and feasible for testing the elastic properties of zebrafish.

Lung edema is a common symptom of congestive heart failure and inflammatory conditions, such as acute respiratory distress syndrome. Currently, computed tomography (CT) is considered the standard to assess lung edema, but it requires ionizing radiation and poses a significant logistic burden. Lung ultrasound (LUS) has previously been used to assess lung edema using ultrasound B-line artifacts, but analysis of the B-line artifacts relies on visual interpretation. We developed lung ultrasound surface wave elastography (LUSWE) to measure lung surface wave speed safely. This project aims to evaluate LUSWE to quantify lung surface wave speed in an ex vivo water-filled swine lung. The lung surface wave speeds were measured at baseline and at frequencies of 100 Hz, 200 Hz, 300 Hz, and 400 Hz. Then, an amount of water was 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. An additional 120 ml of water was then filled into the lung. The lung surface wave speeds were measured again. The results demonstrated that the lung surface wave speed decreased with respect to water content.

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.