MR defecography is a specialized type of dynamic MRI of the pelvic floor that is typically performed with rectal contrast but without IV contrast and includes MRI acquisition during active defecation of rectal contrast. Multiple Pelvic Floor Dysfunction in Females studies have demonstrated the added benefit of MRI with rectal contrast and the defecation phase for assessment of POP compared with dynamic straining MRI without rectal contrast or defecation [15,26-29]. Although MR defecography can be performed in upright or supine positions, most centers lack an open magnet to allow imaging in the upright position. Studies comparing MR defecography in supine position to that in upright position have shown variable results depending on site of prolapse. Some authors have reported that MR defecography in supine positioning may underestimate detection and size of rectal intussusception and rectocele [30,31], whereas other authors [32] demonstrated no significant difference in prevalence of cystocele or anorectal descent during defecation when comparing the two positions. Regardless of positioning, patients should be asked to perform repeated strain/defecation maneuvers to maximize the size of organ prolapse seen on MRI [33]. MR defecography has moderate correlation with surgical findings for diagnosis of full thickness rectal prolapse, internal rectal prolapse, posterior colopocele, rectocele, and peritoneocele; however, agreement between imaging and surgical findings is lower for MR defecography than CCP for full-thickness rectal prolapse, internal rectal prolapse, and peritoneocele. MR defecography sensitivity for internal rectal prolapse and peritoneocele was not significantly lower than that of CCP in one study [23]. MR defecography agreement with physical examination is best for prolapse in the anterior compartment (85%) compared with middle compartment (63%) and posterior compartment (79%).
Pelvic Floor Dysfunction in Females. MR defecography is a specialized type of dynamic MRI of the pelvic floor that is typically performed with rectal contrast but without IV contrast and includes MRI acquisition during active defecation of rectal contrast. Multiple Pelvic Floor Dysfunction in Females studies have demonstrated the added benefit of MRI with rectal contrast and the defecation phase for assessment of POP compared with dynamic straining MRI without rectal contrast or defecation [15,26-29]. Although MR defecography can be performed in upright or supine positions, most centers lack an open magnet to allow imaging in the upright position. Studies comparing MR defecography in supine position to that in upright position have shown variable results depending on site of prolapse. Some authors have reported that MR defecography in supine positioning may underestimate detection and size of rectal intussusception and rectocele [30,31], whereas other authors [32] demonstrated no significant difference in prevalence of cystocele or anorectal descent during defecation when comparing the two positions. Regardless of positioning, patients should be asked to perform repeated strain/defecation maneuvers to maximize the size of organ prolapse seen on MRI [33]. MR defecography has moderate correlation with surgical findings for diagnosis of full thickness rectal prolapse, internal rectal prolapse, posterior colopocele, rectocele, and peritoneocele; however, agreement between imaging and surgical findings is lower for MR defecography than CCP for full-thickness rectal prolapse, internal rectal prolapse, and peritoneocele. MR defecography sensitivity for internal rectal prolapse and peritoneocele was not significantly lower than that of CCP in one study [23]. MR defecography agreement with physical examination is best for prolapse in the anterior compartment (85%) compared with middle compartment (63%) and posterior compartment (79%).