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Gastrointestinal Imaging

E2811. MR Defecography: Structuring a Report to Better Help the Surgeon

Perez L,  Yoon D,  Kagen A. Mt. Sinai West–St. Luke’s Hospital, New York, NY

Address correspondence to L. Perez (luiperez@chpnet.org)

Background Information: Pelvic floor dysfunction affects approximately 50% of women above the age of 50 and may have a significant impact on quality of life. It consists of multiple conditions, such as urinary incontinence, fecal incontinence, defecatory dysfunction, and pelvic organ prolapse. Female sex, menopause, and aging constitute the main risk factors. Weakness of the pelvic floor can involve the anterior, middle, and posterior compartments, causing abnormal descent of different pelvic structures simultaneously. Conditions in different compartments often coexist; therefore, adequate assessment should be performed to properly make a diagnosis and to provide the most optimal treatment. Dynamic MR defecography is an excellent diagnostic tool in evaluating pelvic dysfunction. Its superior soft-tissue contrast resolution allows detailed investigation of all the pelvic floor compartments and their supportive structures in a single examination, which is vital when communicating the findings to the surgeon with the uppermost precision.

Educational Goals/Teaching Points: The educational goals are to depict the role of MRI in pelvic floor dysfunction, review the proper terminology related to pelvic floor dysfunction, and demonstrate how to thoroughly evaluate functional abnormalities and effectively help surgeons in guiding and providing the most appropriate treatment with the purpose of avoiding disease recurrence. MR defecography has proven to be advantageous in the assessment of pelvic floor dysfunction by simultaneously evaluating multiple compartments of the pelvic floor. The pubococcygeal line (PCL) is drawn from the inferior border of the symphysis pubis to the last coccygeal joint in midsagittal plane. The H-line corresponds to the anteroposterior width of the levator hiatus, and the M-line is the perpendicular distance between the PCL and the anorectal junction. Multiple well-established grading systems using different combinations of measurements are used to determine which patients are surgical candidates.

Key Anatomic/Physiologic Issues and Imaging Findings/Techniques: The imaging technique consists of first, asking for the patient’s permission, then placing an enema to clear the bowel prior to the examination by rectal filling with 60 milliliters of warm ultrasound gel via a tapered tip 60-mL syringe through a Foley catheter. Next, T1-weighted large FOV sequences are acquired to identify a midline sagittal plane. Subsequently, T2-weighted sequences are obtained in axial, sagittal, and coronal planes to image the pelvic anatomy, and T2-weighted fast-spin-echo sequences are used to assess for muscle defects. Finally, the dynamic study using steady-state sequences is performed by acquiring cine images in the sagittal plane at rest, squeezing (Kegels), straining, and defecation.

Conclusion: Pelvic floor dysfunction may have a major impact on quality of life of those affected. Clinical examination is not always sufficient in diagnosing the extent of prolapse or assessing evacuation. MR defecography provides an accurate diagnosis for proper management and surgical intervention.