Radiologic Features of Extraperitoneal Effusions

Criteria for radiological diagnosis of specific compartmentalization of extraperitoneal fluid and its possible sources were developed by (a) determining pathways of extraperitoneal fluid flow and establishing preferential routes of spread from various sites; (b) establishing fascial boundaries which direct and compartmentalize extraperitoneal fluid collections; and (c) defining the role of peritoneal reflections in the passage of exudates. The correlation of the distribution of fluid with the extraperitoneal fascial planes is based on cross-sectional planes derived from frozen cadavers, postmortem injection studies, and selected clinical cases in various disease states.