Computed tomography of the diaphragm: peridiaphragmatic fluid localization.

Fifty-eight consecutive cases of peridiaphragmatic fluid collections were correctly localized by computed tomography. The key to accurate localization of peridiaphragmatic fluid is identification of the hemidiaphragms. Pulmonary consolidation and pleural fluid collections lie adjacent and peripheral to the convexity of the hemidiaphragms. Free pleural fluid distends the posterior pleural recesses, important anatomic landmarks beneath the bases of the lungs. Intra-abdominal fluid collections lie adjacent and central to the convexity of the hemidiaphragms. On the right side intraperitoneal fluid is restricted from contact with the bare area of the liver by the coronary ligaments. It is concluded that peridiaphragmatic fluid collections can generally be readily identified if one is familiar with normal cross-sectional anatomy.