[Pelvic endometriosis]

Endometriosis is a common disease that affects about 20% of women of childbearing age. At transabdominal and endovaginal ultrasound, in 90% of cases, ovarian endometriosis appears as a homogeneous lesion with low level echoes most often associated with clots. However this modality is insufficient to detect associated lesions. MRI is as accurate as ultrasound to detect ovarian endometriosis which most often appears with a signal higher than that of adipose tissue on T1W images and a bright signal area on fat suppressed images. The main advantage of this examination is not only to detect small ovarian implants but to also detect associated subperitoneal implants. These lesions involving the bladder as well as posterior structures such as the uterosacral ligaments, rectovaginal septum, and rectum appear as fibromuscular masses containing hyperintense signal areas on T1W images, or as purely fibrotic lesions that can be quite difficult to diagnose. Laparoscopy remains the procedure of choice to detect peritoneal implants.