CT demonstration of preferential routes of the spread of pelvic disease.

Specific anatomical pathways, both extraperitoneal and intraperitoneal, exist which result in the spread of disease into or out of the pelvis. Often, the full extent of the disease is not appreciated clinically and may be uncovered first by computed tomography (CT). This review discusses the pertinent normal anatomy as shown by CT and magnetic resonance (MR) and then illustrates each route with examples. An awareness of these preferential routes of disease spread permits the radiologist monitoring the examination to decide when areas adjacent to the pelvis should be included in the study. This will provide a complete assessment of the extent of disease and guide appropriate therapy.