ABSTRACT
This chapter discusses the embryology and anatomy of the peritoneal cavity, different imaging modalities used to image the region, and the imaging appearance of pathology within the peritoneal cavity. To visualize peritoneal pathology, a scan of the abdomen and pelvis is performed post intravenous contrast. The peritoneal recesses within peritoneal cavity are in anatomic continuity, punctuated by mesenteries, ligaments, and fasciae, which may confine pathology or provide routes for disease spread. The anatomic configuration of the peritoneal cavity and the dynamic flow of intraperitoneal fluid and cells produce pathology with characteristic radiological appearances. Some ulcers will seal off immediately; the only radiological sign of perforation may be a small locule of gas adjacent to the stomach or in the gastroduodenal ligament. Radiological features suspicious for malignancy include asymmetrical wall thickening, shouldering, and large local nodes, but these features are nonspecific and direct visualization will be required in these cases.
