The perihepatic spaces: computed tomographic and ultrasound imaging.

The appearance of perihepatic fluid collections on sectional imaging is discussed. The coronary ligamentous attachments of the right lobe of the liver to the diaphragm delineate a bare area that separates the right subphrenic and posterior subhepatic spaces. These attachments explain the configuration of right perihepatic fluid collections on sectional images and allow differentiation of subphrenic, posterior subhepatic, and pleural fluid with ultrasound and computed tomography. More medially, the caudate lobe of the liver invaginates the superior recess of the lesser sac, so that fluid collections within this recess may mimic intrahepatic masses on sectional images. This is illustrated with anatomic sections, computed tomographic scans, and ultrasound images.