[Computed tomography-based virtual colonoscopy: an examination useful for the choice of the surgical management of colorectal endometriosis]

OBJECTIVE: To evaluate the use of computed tomography-based virtual colonoscopy in the preoperative assessment of colorectal endometriosis. PATIENTS AND METHODS: We included in the study consecutive women undergoing surgical management of deep infiltrating endometriosis from August 2009 to April 2010, whose colorectal involvement had been assessed by magnetic resonance imaging (MRI) and rectal endoscopic sonography (RES). Prior to surgical procedure, a computed tomography-based virtual coloscopy was performed. Computed tomography was performed by insufflating air into the distal rectum, along with an intravenous injection of contrast agent. Then, 3D reconstruction of pictures was carried out, to allow visualization of the lumen of the rectum and the colon. Data provided by virtual colonoscopy were compared to those given by other imaging techniques and surgical exploration. RESULTS: Twenty-seven patients were included in the study: 7 women underwent colorectal segmental resection, 2 full thickness excision, 15 shaving, while in 3 of them no digestive surgical step was performed. Virtual colonoscopy provided the measurement of the length and the diameter of colorectal stenosis due to infiltrating nodule through rectal and sigmoid wall, which was presenting as an endoluminal indentation. The number of patients presenting with endometriotic nodules arising on the rectum, sigmoid colon, or both of them, were respectively 13, 7 and 7. Ovarian endometriomas were responsible for extrinsic compression leading to digestive tract stenosis in nine cases. The number of lesions and their height reported to the anus were accurately assessed in 24 women out of 27 (sensitivity of 88%). The origin of the digestive tract stenosis, i.e. either infiltrating endometriotic nodules or extrinsic compression due to ovarian endometriomas, was accurately assessed in all cases, by combining information provided by virtual colonoscopy, IRM, RES and transvaginal ultrasonography. CONCLUSION: Computed tomography-based virtual colonoscopy provides useful information about the degree and the height of digestive tract stenosis due to colorectal endometriosis. In our opinion, this information is of major interest to argue the choice of shaving or full thickness excision of nodules in a majority of women presenting with colorectal endometriosis.