MR Imaging Accurately Depicts Deep Endometriosis

Preoperative MR imaging may help radiologists diagnose deep endometriosis and more precisely characterize extent of disease, thereby aiding in treatment planning, according to a study published in Radiology online in July 2009 and in the October 2009 print edition.

Nathalie Hottat, M.D. Université Libre de Bruxelles’ Erasme Hospital

Neal C. Dalrymple, M.D. South Texas Radiology Group

Marco A. Amendola, M.D. Innovative Cancer Institute

Assessing the disease by physical examination alone is difficult, according to lead author Nathalie Hottat, M.D.

"3T pelvic MR imaging in the preoperative staging of endometriosis is a feasible routine technique that has significant correlation with histologic results and therefore has a positive impact on the management of patients," said Dr. Hottat, of the Department of Radiology at Université Libre de Bruxelles' Erasme Hospital in Brussels, Belgium. "This examination can orient the type of surgery—endoscopy versus laparotomy—and provide a roadmap to the surgeon in patients suffering from endometriosis."

More than 5 million American women suffer from endometriosis, a chronic and painful disease that results when endometrium grows outside of the uterus and attaches to other organs such as the ovaries, fallopian tubes, bowels and bladder, according to the U.S. Department of Health and Human Services.

"Endometriosis is present in 10 percent of women of childbearing age and in 25 to 35 percent of women with infertility," said Dr. Hottat. "Deep endometriosis is a more severe form of endometriosis because it can extend to pelvic organs—including 6 to 30 percent of the cases of endometriosis of the colon—and the bladder."

While superficial endometriosis can be treated with lasers during laparoscopy, deep endometriosis sometimes requires complete surgical excision of the lesions. Although some drugs can stabilize the disease, the only curative treatment is surgery, said Dr. Hottat.

The difference in intervention/treatment methods makes it imperative for the surgeon to evaluate the extent of the disease before planning surgery.

Study Shows High Sensitivity, Specificity

Between March 2007 and August 2008, researchers studied 41 women ages 20 to 46 with suspected endometriosis. MR imaging was performed on all patients prior to surgery.

Results showed that MR imaging accurately diagnosed 26 of 27 cases of deep endometriosis and that images accurately depicted specific locations of deep endometrial lesions.

The study found that 3T MR imaging demonstrated 96.3 percent sensitivity and 100 percent specificity for diagnosing deep endometriosis. It also showed that the colon wall was involved in 32 percent of the patients with deep endometriosis and MR imaging was effective in distinguishing different layers of the affected portion and accurately showed the degree of colon wall invasion.

Further Research Needed

Preoperative MR imaging may help radiologists diagnose deep endometriosis and more precisely characterize extent of disease, according to a new study in Radiology. Axial high-spatial-resolution turbo spin-echo T2-weighted flow-compensated T2-weighted MR images (repetition time, respiratory period; echo time, 135 msec) in a 21-year-old woman. There is deep endometriosis infiltrating the right ulterosacral ligaments (short arrow), pelvic muscle and colon wall (long arrow). Image shows circumferential rectosigmoid stenosis due to deep endometriosis (x) visualized after administration of intrarectal ultrasonographic gel (* = rectosigmoid lumen filled with gel). The different sublayers can be distinguished (arrowhead = mucosa, short straight arrow = submucosa, curved arrow = muscularis, long straight arrow = serosa). At MR imaging and pathologic examination, the colon wall infiltration was graded as involving the mucosa. Radiology 2009;253:126–134

Although research showed that MR imaging can accurately diagnose disease with minimal discomfort to patients, Dr. Hottat pointed out that the small sample size could be a limitation.

Dr. Hottat noted the mean time of 60 days between MR imaging examination and surgery as a potential limitation. "However, since deep endometriosis is a chronic disease, we don't expect this delay to dramatically bias our results," she said.

Although Neal C. Dalrymple, M.D., a radiologist at South Texas Radiology Group in San Antonio, said the study made him optimistic about better diagnosis of deep endometriosis, he agreed more research is required.

"The surgeons in the study were aware of the depth of the disease because they reviewed the MR findings before they went into surgery," said Dr. Dalrymple, a member of the genitourinary radiology subcommittee of the RSNA Scientific Program Committee and author of the book, "Problem Solving in Abdominal Imaging."

"I don't know how feasible it is, but I'd like to see a future study where surgeons not currently using MR for preoperative planning were given MR results after performing the initial surgical exploration but before the procedure was over. That might provide more insight into the value added by MR," he said.

MR Imaging Could Aid Up-Front Diagnosis

Marco A. Amendola, M.D., director of medical imaging at the Innovative Cancer Institute in Miami, and also a member of the genitourinary radiology subcommittee of the RSNA Scientific Program Committee, concurred with Dr. Dalrymple that preoperative diagnosis of deep endometriosis is challenging and has so far been more successful in academic centers than in community practice.

"Knowledge of the precise distribution and extension of endometriosis is essential for the surgeon," said Dr. Amendola. "Excision of deep endometriosis is technically very demanding and is associated with high surgical risk including the need for colostomy."

Because deep endometriosis is underdiagnosed, Dr. Dalrymple said he is hopeful that MR imaging will allow earlier more definitive diagnosis.

"We don't really know how many women have deep endometriosis," he said. "In my experience, we usually go searching for deep endometriosis in women who fail treatment for surface disease. MR imaging has the potential to let us diagnose deep endometriosis up front."

Additionally, preoperative MR imaging could help reduce anxiety in patients and physicians by eliminating some of the variables, Dr. Dalrymple added.

"I think it gives both the surgeon and the patient more confidence to go into a procedure with a plan, aware of the extent of disease preoperatively rather than discovering it during surgery."