Lung Ultrasonography Phantom for Lung-Pulse Sign Simulation

Lung ultrasonography (LUS) is a diagnostic tool increasingly utilized in intensive care. Impedance difference between alveoli air and chest wall tissues impairs deep penetration of ultrasound signal, generating a horizontal hyperechoic artifact pattern, called A-lines. Atelectasis is air absence in a lung, making ultrasound signal easier to identify a heart rate pulsation in pleural line, so-called lung-pulse sign. M-mode allows objectification of this pattern. The aim of this study is to propose a LUS phantom that simulates both lung-pulse sign and A-lines artifacts. Polyvinyl chloride plasticizer (PVCP) was the base of thoracic wall phantom confection. A thin-walled silicone tube was inserted through the phantom and connected to a peristaltic pump, offering 84 cycles per minute rate to simulate heart activity. A commercial latex condom coated a polyurethane foam to simulate the pleura and lung parenchyma, respectively. Images were obtained on commercial clinical ultrasound equipment with the linear transducer, which was fixed with an articulated vise in a vertical position in contact with thoracic wall phantom. Lung phantom without air (withdrawal by syringe) was introduced into the thoracic phantom next to the silicone tube and to the wall where the transducer was positioned. A peristaltic pump was turned on and images started to be acquired. Subsequently, an experimental setup was reorganized for new images acquisition with lung phantom completely opened and motionless. In the results, first images replicated collapsed lung, with visible lung-pulse sign; and second setup mimicked opened lung A-lines, with suppression of lung-pulse.