ABSTRACT
The advantages of ultrasound (US) over standard chest radiography and computed tomography (CT) include the absence of radiation, portability, real-time imaging, and the ability to perform dynamic evaluations. Diaphragmatic movement can also be visualized in real time, and is a key reference point when starting to perform US examination of the pleural space. The ability of US to dynamically image the chest has proved beneficial in differentiating subpulmonic effusions from an elevated hemidiaphragm, and US is also nearly as sensitive as CT scanning in distinguishing atelectasis from effusion when the chest X-ray reveals opacification of the hemithorax. The volume of fluid in the pleural space can also be sonographically estimated, and when examining patients who are in the supine position, the volume of fluid seen on US correlates better with actual fluid volume than the amount of fluid estimated from a lateral decubitus chest X-ray.
