E5106. Intraabdominal Air: Peritoneal Anatomy is the Key to Enter the Pandora Box
  1. Charanjeet Singh; Yale University
Knowledge of peritoneal anatomy is the key for radiologists to accurately identify the spread of gas, tumors, and fluid collections across the peritoneal spaces at cross-sectional imaging. The peritoneal gas, infectious, inflammatory, neoplastic, and traumatic processes frequently seen within peritoneal cavity, involving its reflections; thus, it is important to identify the affected peritoneal spaces and the ligaments. Knowledge of these structures is important for accurate reporting and helps elucidate the sites of perforation to the surgeon. It is important for the radiologist to endeavor to locate the site of potential perforation to allow the surgeon to determine the site of incision, especially if laparoscopic surgery is planned.

Educational Goals / Teaching Points
Understand peritoneal anatomy and how this affects the distribution of air within the peritoneal and extraperitoneal regions and use this to determine the most likely site of perforation. Know the most common sites and causes of perforation and their imaging appearances. Identify specific imaging signs that allow accurate localization of the site of perforation.

Key Anatomic/Physiologic Issues and Imaging Findings/Techniques
Peritoneal anatomy: from embryo to adult. Peritoneal reflections including attachments of different visceral mesentery, peritoneal ligaments, cavities/sacs, and retroperitoneal organs. Intraabdominal gas: Location of gas, secondary signs, and localization of the site of the perforation. Causes (cases): perforated gastric or duodenal ulcer, perforated diverticulitis, perforated appendix, perforated a small bowel, esophageal perforation, pneumatosis intestinalis, portal venous gas, pneumobilia, retroperitoneal gas. Potential punctate pitfalls in the diagnosis of free intraabdominal gas.

By completing this presentation, readers will better understand the peritoneal anatomy, various spaces and ligaments of the peritoneal reflection, spectrum of intraabdominal gas at various locations and, consequently, be better equipped to identify them, as well to prevent or to timely initiate aggressive intervention/surgery.