Abstract
Ultrasonography enables the examiner to detect very small amounts of fluid in the peritoneal cavity and to determine its location, amount, and sonographic features. The pathologic process responsible for the ascites, for example, ileus, hepatic fibrosis, thrombosis of the caudal vena cava, or traumatic reticuloperitonitis, often can be identified. Abdominocentesis and analysis of the aspirated fluid allow differentiation of inflammatory and noninflammatory ascites as well as the diagnosis of uroperitoneum, hemoperitoneum, chylous ascites, and bile peritonitis.