TVUS had better sensitivity, specificity, PPV, NPV and accuracy in cases of deep retrocervical and rectosigmoid endometriosis when compared with MRI and digital vaginal examination, confirming that it is an important preoperative examination for the definition of surgical strategies.

Endometriosis is a common multifocal gynecologic disease that manifests during the reproductive years, often causing chronic pelvic pain and infertility. It may occur as invasive peritoneal fibrotic nodules and adhesions or as ovarian cysts with hemorrhagic content. Although findings at physical examination may be suggestive, imaging is necessary for definitive diagnosis, patient counseling, and treatment planning. The imaging techniques that are most useful for preoperative disease mapping are transvaginal ultrasonography (US) after bowel preparation, and magnetic resonance (MR) imaging. Initial transvaginal US is a reliable technique for detecting rectosigmoid endometriotic lesions. MR imaging is indicated as a complementary examination in complex cases of endometriosis with extensive adhesions and ureteral involvement. Peritoneal endometriotic implants are typically hypoechoic on transvaginal US images and demonstrate low signal intensity on T2-weighted MR images. Endometriotic implants most commonly are found in retrocervical and rectosigmoid sites, followed by the vagina, bladder, and ureters. Cysts with low-level internal echoes and echogenic peripheral foci at transvaginal US are suggestive of endometriomas. MR imaging has high specificity for identifying endometriomas, which are characterized by high signal intensity on T1-weighted images and low signal intensity on T2-weighted images. Correlation of the radiologic imaging features of endometriotic lesions with their laparoscopic appearances may help improve individual proficiency in the radiologic diagnosis of endometriosis.

Endometriosis is defined as the presence of endometrial tissue that is located outside the uterine cavity and associated with fibrosis and inflammatory reaction. It is a polymorphic and multifocal disease with no known cure or preventive mechanisms. Patients may be asymptomatic or may experience chronic pelvic pain, dysmenorrhea, dyspareunia, or infertility. The pelvic cavity is the most common location for endometriotic implants, which usually affect the retrocervical space, ovaries, vagina, rectosigmoid colon, bladder dome, and round ligaments. Atypical endometriosis is rare and difficult to diagnose. The most common atypical locations are the gastrointestinal tract, urinary tract, lung, umbilicus, inguinal area, breast, and pelvic nerves, as well as abdominal surgical scars. Gastrointestinal lesions are the most common extragenital manifestation, and the diaphragm is the most frequent extrapelvic site. The catamenial nature of the symptoms (occurring between 24 hours before and 72 hours after the onset of menstruation) may help suggest the diagnosis, but imaging by specialists is fundamental to evaluation. Depending on the area affected, radiography, ultrasonography, thin-section computed tomography, or magnetic resonance imaging can be used to assess suspected lesions. Because isolated extragenital endometriosis is rare, concomitant evaluation of the pelvic cavity is mandatory. Surgical excision is the only therapeutic option for definitive treatment, and comprehensive disease mapping is necessary to avoid residual disease. The authors review atypical locations for endometriosis and emphasize the most appropriate imaging protocols for investigation of various clinical manifestations. Online supplemental material is available for this article. RSNA, 2018.

MRI demonstrates high accuracy in diagnosing DIE in the retrocervical region, rectosigmoid, bladder, ureters, and vagina.

Deeply infiltrating endometriosis (DIE) is a common gynecologic disease that is characterized by a difficult and delayed diagnosis. Radiologic mapping of the DIE lesion sites is crucial for case management, patient counseling, and surgical planning. Transvaginal ultrasonography (US) is the initial imaging modality for investigating DIE and has been the focus of several recent studies. DIE typically manifests at imaging as hypoechogenic nodules throughout the affected sites and thickening of the intestinal wall, with some lesions showing a mixed pattern due to cystic areas. Transvaginal US performed after bowel preparation improves the ability to diagnose intestinal lesions and provides invaluable details, including which layers of the intestine are affected and the distance between the lesion and the anal border. It is vital that radiologists be familiar with the technical aspects of this modality and with the US manifestations of DIE lesions. Transvaginal US performed after bowel preparation should be the first-line imaging modality for the evaluation of women with suspected endometriosis.