July 7 (HealthDay News) -- MRI can successfully diagnose deep endometriosis and offers surgeons a better map to finding wayward uterine tissue that needs to be removed, a new study suggests.

All but one of 27 cases of deep endometriosis -- in which uterine tissue (endometrium) grows and attaches to areas such as the cervix, vagina or colon -- were detected via MRI, with the location of deep lesions being accurately indicated on the images, according to the study published online in Radiology.

Endometriosis, which affects about 5 million women in the United States, can cause chronic pain in the pelvis and lower back, lead to painful sexual intercourse and menstrual cramps, and result in fatigue and infertility. Minimally invasive laparoscopy can treat superficial endometriosis, but deeper lesions, known as subperitoneal endometriosis, require more extensive surgery.

MRI was able to distinguish between all cases of superficial and deep endometriosis, the study found, and even differentiated between affected colon wall layers in the 32 percent of the study participants who had endometriosis in that area of their body.

"MRI findings accurately ruled out deep endometriosis in patients with superficial endometriosis, allowing the surgeon to perform the less-invasive laparoscopic procedure," the study's lead author, Dr. Nathalie Hottat, from the radiology department of Erasme Hospital in Brussels, Belgium, said in a news release from the Radiological Society of North America.

SOURCE: Radiological Society of North America, news release, July 7, 2009