Prospective Comparison between two different magnetic resonance defecography techniques for evaluating pelvic floor disorders: air-balloon versus gel for rectal filling.

Purpose: to prospectively compare two rectal filling techniques for dynamic MRI of pelvic floor disorders (PFD).

Methods And Materials: Twenty-six patients with PFD underwent the two techniques during the same procedure, one based on rectal placement of a balloon-catheter filled with saline and air insufflation (air-balloon technique or AB); another based on rectal filling with 180 cc of gel (gel-filling technique or GF). The examinations were compared for assessment and staging of PFD, including rectal-descent, rectocele, cystocele, colpocele, enterocele, rectal invagination. Surgery and clinical examinations were the gold standard.

Results: AB showed sensitivity of 96 % for rectal descent, 100 % for both rectocele and colpocele, 86 % for rectal invagination and 100 % for enterocele; understaged 11 % of rectal descents and 19 % of rectoceles. GF showed sensitivity of 100 % for rectal descent, 91 % for rectocele, 83 % for colpocele, 100 % for rectal invagination and 73 % for enterocele; understaged 3.8 % of rectal descent and 11.5 % of rectoceles. Both techniques showed 100 % of specificity. Agreement between air-balloon and gel filling was 84 % for rectal descent, 69 % for rectocele, 88 % for rectal invagination, 84 % for enterocele, 88 % for cystocele and 92 % for colpocele.

Conclusion: Both techniques allowed a satisfactory evaluation of PFD. The gel filling was superior for rectal invagination, the air-balloon for rectocele and anterior/middle compartment disorders.

Key Points: • A standardized MRI technique for assessing pelvic floor disorders is not yet established. • This study compares two MRI techniques based on different rectal filling: air-balloon versus gel. • Both MRI techniques proved to be valuable in assessing PFD, with good agreement. • Air-balloon technique is more hygienic and better tolerated than the gel-filling technique. • Gel was superior for rectal invagination, air-balloon for rectocele and uro-genital prolapses.