Diaphragmatic discontinuity associated with perihepatic ascites: a sonographic refractive artifact

Apparent discontinuity in the diaphragm frequently is seen in sonograms of the right upper quadrant in patients with perihepatic ascites. Using a fresh cadaveric liver and a linear reflector to simulate the diaphragm, we performed in vitro analysis and confirmed that the appearance of the diaphragm was artifactual; this was due to refraction of the sound beam at the interface between the liver and ascites. Knowledge of the typical sonographic appearance and location of this artifact should prevent diagnostic errors.