Sonography for pelvic endometriosis

The main diagnostic problems for endometriosis are detection of the disease, especially in the absence of ovarian endometriotic cysts, and evaluation of the extent of disease in the pelvis. Transvaginal ultrasonography (TVS) has been proposed as the first line-line imaging technique thanks to its wide availability and because it enables extensive exploration of the pelvis. The “typical” endometrioma is a unilocular cyst with homogeneous low-level echogenicity (ground-glass echogenicity) of the cyst fluid. The use of color Doppler helps to avoid the classification of malignancies as endometriomas by defining the presence or not of flow in papillations. Real-time dynamic TVS examination of adhesions and pouch of Douglas (POD) obliteration, using the sliding sign technique, may be useful in the identification of women at increased risk for bowel endometriosis. Utilizing TVS, an accurate assessment of the vagina—particularly the areas of the posterior and lateral vaginal fornices, the retrocervical area with torus uterinum and uterosacral ligaments as well as the rectovaginal septum—should be made. A slightly filled bladder facilitates evaluation of the structure of the bladder walls and the presence of endometriotic nodules, which appears as hypoechoic linear or spherical lesions bulging toward the lumen, involving the serosa, muscularis, and/or (sub)mucosa of the bladder. Deep nodes of the rectum appear as hypoechoic lesions, linear or nodular retroperitoneal thickening with irregular borders and a few vessels at power Doppler evaluation, penetrating into the intestinal wall distorting its normal structure. Sonographic evaluation of the pelvis also allows a noninvasive classification of the disease to be made, according the Enzian and the AAGL classification, in order to perform presurgical staging.