Comparison of Erect Sitting and Supine MRI Proctography in Women with Pelvic Organ Prolapse and Defecatory Symptoms

INTRODUCTION AND HYPOTHESIS: The optimal position for MRI proctography in women suffering from pelvic organ prolapse (POP) and defecatory symptoms remains uncertain. Typically, MRI proctography is performed in the supine position to assess for POP. Utilising an open-configuration MRI to image the pelvic floor in an erect sitting position may provide a more physiological assessment than a supine MRI for the evaluation of pelvic floor dysfunction. The aim was to compare the findings of MRI proctography performed in the conventional supine position compared with the erect sitting position in women with POP and defecatory symptoms. METHODS: We performed a retrospective review of 333 women referred to a tertiary referral centre with POP and defecatory symptoms who underwent MRI proctography over a 4-year period. Of these, 144 women were imaged in the supine position and 189 women in the erect sitting position. Radiological findings of rectocele, rectal intussusception, enterocele, impaired defecation, and pelvic floor descent were compared. RESULTS: Pelvic floor descent was identified in significantly more women in the erect sitting position (37.0%) than in the supine position (12.5%; p < 0.001). Similarly, rectal intussusception during straining was detected in significantly more women imaged in the erect sitting position (49.7%) than in the supine group (33.3%; p = 0.003). Enterocele was identified more frequently in the erect sitting position group (4.8% versus 0.7%; p = 0.048). Impaired defecation was identified more frequently in the supine group (56.9% versus 45.0%; p = 0.030). There were no significant differences in the prevalence of anterior rectocele between the two groups of women. CONCLUSION: Erect sitting MRI proctography was associated with higher detection rates of pelvic floor descent, enterocele and rectal intussusception during straining. These findings suggest that patient positioning might influence the identification of certain pelvic floor abnormalities in the more physiological erect sitting position.