Objective: To retrospectively determine the accuracy of MRI rectal and pararectal signs in predicting the necessity for segmental resection in the case of lesions located in the rectum.
Methods: MR images of consecutive patients treated for rectal endometriosis over a 5-year period were reviewed in consensus by two blinded readers. A systematic analysis of 7 rectal (lesion length, transverse axis, thickness and circumference, and presence of a convex base, submucosal oedema and hyperintense cystic areas) and 4 pararectal (posterior vaginal fornix, parametrial, ureteral and sacro-recto-genital septum involvements) signs was performed for each lesion. MRI results were compared to the surgical procedure performed (shaving versus segmental resection).
Results: Among 61 patients studied, 32 received a segmental resection and 29, a shaving. Receiver operating characteristic curve analysis allowed determining cut-off values for length (≥ 32 mm), transverse axis (≥ 22 mm), thickness (≥ 14 mm) and circumference (≥ 3/8 radii). The 7 rectal signs, and only the sacro-recto-genital septum pararectal sign, were significantly associated with segmental resection in univariate analysis, nodular thickness ≥ 14 mm and circumference ≥ 3/8 radii being the most predictive signs (odds ratio 94.5 and 60.4, respectively). These 2 signs remained positively associated with segmental resection in multivariate analysis and, when combined, were predictive of segmental resection with an accuracy of 90.2%.
Conclusion: Assessing MRI rectal and pararectal signs may accurately predict the need for segmental resection versus a more conservative approach such as shaving for rectal lesion management.
Key points: • MRI analysis of rectal endometriosis, taking into account rectal and pararectal signs, may assist surgeons in the decision-making process, in counselling patients regarding the surgical procedure and in adequately allocating resources. • Among rectal signs, nodular thickness ≥ 14 mm and a circumference ≥ 38% were the most predictive signs of segmental resection. • Among pararectal signs, only the sacro-recto-genital septum involvement was significantly associated with segmental resection.
Keywords: Digestive system surgical procedures; Endometriosis; Magnetic resonance imaging; Rectum.