Magnetic Resonance Defecography: typical and atypical findings.
Type:Educational Electronic Presentation
Authors: Eduardo Negrão, Beatriz Flor de Lima, Daniela Pinto, António J. Madureira
Keywords:MRI, Defecography, Pelvic Floor
Educational objective

Review the most common functional disorders of the pelvic floor, such as organ prolapse and obstructed defecation syndrome.

Discuss the proper magnetic resonance imaging technique, adding some tips and tricks in optimizing the appropriate protocol.

Review uncommon findings, such as posterior rectoceles and partial organ prolapses that change throughout the dynamic study.

Topic Review

The pelvic floor comprises all the structures supporting the abdominal and pelvic cavity, mostly muscles and ligaments. A musculofascial diaphragm provides static support for pelvic visceral organs, and its major components are: the endopelvic fascia, which supports the pelvic organs at different levels; the levator ani and its most important muscles – the puborectalis and iliooccygeus; the perineal body, in which the perineal muscles and external anal sphincter insert.

Pelvic floor disorders occur more commonly in women, including a spectrum of functional disorders, such as urinary incontinence, pelvic organ prolapse and defecatory dysfunction. General symptoms range from pelvic pain and discomfort to incomplete bowel voiding. Around 50% of women over 50 years of age are affected, and many will require surgery.


Magnetic resonance imaging (MRI) has... more

Fig.1: (A) Coronal T2-weighted MR image showing normal anatomy of the iliococcygeous muscle (yellow arrows) and the puborectalis muscle (red arrows); (B) Sagital T2-weighted MR image shows the differente pelvic compartments: anterior with bladder and urethra (red); middle with uterus and vagina (green); cul-de-sac (peritoneum), posterior with rectum and anal canal (blue).
Fig. 2: T2-weighted MR image on axial plane showing a posterior sagging of the right posterior side of the bladder, reflecting an endopelvic fascia defect (“saddlebag bladder”).


MRI is the preferred technique for pelvic floor assessment, particularly when it involves multiple compartments.

Learning the basic anatomic and dynamic assessment of the pelvic floor is of the utmost importance to aid the clinician in obtaining an accurate diagnosis.

Basic measurements such as the pubo-coccygeal line, M and H lines, and ano-rectal angle are the staple of MRI defecography assessment, and attention should be paid to the common and uncommon findings.



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