Inferior vena caval occlusion: characteristic radiographic changes on excretory urography and barium enema examination.

Acute occlusion of the inferior vena cava produces characteristic radiographic findings on intravenous urogram and barium enema examination. The urinary bladder is compressed anteriorly and superiorly giving an inverted pear-shaped appearance, and the distal ureters are medially displaced. Barium enema examinations demonstrate narrowing and elevation of the rectosigmoid region along with an increase in the presacral space. Four cases are described to illustrate the usefulness of these findings in suggesting the correct diagnosis.