Radiological detection and diagnosis of pouch of Douglas lesions.

The pouch of Douglas (cul-de-sac) represents the caudal extension of the peritoneal cavity. It is the rectovaginal pouch in the female and the rectovesical pouch in the male. The cul-de-sac is in a dependent position when either upright or supine; it is, therefore, a frequent location for seeded lesions. Abnormalities in the cul-de-sac include metastases, abscesses, and endometriosis. These lesions may be detected by multiple modalities, including barium enema, computed tomography, and ultrasound. Examples of numerous cul-de-sac lesions are presented as they appear with different imaging modalities.