Dynamic MR imaging compared with evacuation proctography when evaluating anorectal configuration and pelvic floor movement.

Abstract

The aim of this study was to determine the agreement between measurements of the anorectal configuration made with dynamic MR imaging and with evacuation proctography. Ten women with constipation were examined sequentially using both standard evacuation proctography and dynamic MR imaging. Correlation and agreement between standard measurements of anorectal configuration at rest and during straining or evacuation of the rectum were evaluated. Significant correlation existed for anorectal junction descent (r = .7, p = .023), change in the anorectal angle (r = .78, p = .008), the position of the rectal axis on straining (r = .62, p = .032), and rectocele depth (r = .82, p = .004). The mean of the measurement differences for anorectal junction descent as measured using the two techniques was -0.23 cm (SD, 1.40 cm). The mean of the measurement differences for change of the anorectal angle was +15.3 degrees (SD, 27.92 degrees). Standard measurements of anorectal configuration made using evacuation proctography and dynamic MR imaging show significant correlation. However, in our study statistical agreement was poor for measurement of anorectal junction descent and anorectal angle change as seen on imaging obtained with the two techniques.