The perihepatic space: comprehensive anatomy and CT features of pathologic conditions.

The liver is covered by visceral peritoneum except at the bare area, bed of the gallbladder, and porta hepatis. The investing peritoneum becomes contiguous with the adjacent structures such as the diaphragmatic peritoneum, lesser omentum, and ligamentum teres. An inflammatory process or tumors involving the perihepatic space are usually affected by intraperitoneal flow dynamics, which depend on the anatomy of the recess as well as gravity and negative subdiaphragmatic pressure. Pathologic conditions that occur in the perihepatic space include abnormal air, fatty masses, conditions producing fluid attenuation at computed tomography (CT), and soft-tissue masses. Enhancement of the hepatic capsule indicates inflammation, as is seen in Fitz-Hugh-Curtis syndrome. The perihepatic ligaments may be invaded by various conditions by means of direct invasion, subperitoneal extension, or extension along the lymphatic vessels. Knowledge of the normal anatomy of the perihepatic space together with the clinical history and characteristic features at CT can assist the radiologist in making the correct diagnosis.