Figure 1: Sagittal T2-weighted image with the patient at rest demonstrates no bladder or uterine prolapse. The rectum demonstrates a bulbous appearance and there is a bulging of the levator ani complex.

Movie 1: Sagittal T2-weighted dynamic images of the patient during different degrees of the Valsalva maneuver demonstrate substantial prolapse of all three compartments. The uterus shows complete descent below the level of the symphysis pubis. Upon second incremental drop in the position of the uterus, the rectum undergoes a re-ascent with an anterior translation such that it returns to a more superior level after the final descent of the uterus. There are some small bowel components that herniated as well with small bowel extending down to the level of the symphysis pubis, in close proximity to the acquired position of the uterine fundus. The uterus did not spontaneously return to the rest position.

Three compartment pelvic floor prolapse.

Pelvic floor weakness is an important and common women's health problem. Pelvic floor weakness primarily affects middle-aged and elderly parous women over 50 years of age, with up to 50% of such women demonstrating some degree of pelvic prolapse. In addition to age, the risk factors for pelvic floor weakness include multiparity, menopause, and obesity. The clinical manifestations of pelvic floor weakness may include abnormal descent of the bladder (cystocele), uterus or vagina (uterine or vaginal vault prolapse), small bowel (enterocele), or rectum (rectocele). Symptoms and signs are present in 10-20% patients and include pelvic pain and pressure, protrusion of tissue through the pelvic floor, urinary and fecal incontinence, constipation, urinary retention, and incomplete defecation.

The mainstay of diagnosis and staging of symptomatic pelvic floor weakness is physical exam, which may involve a complex set of measurements. Physical examination findings are correlated with the patient symptoms to determine treatment. However, in more complex cases with multicompartment involvement or if the physical findings are equivocal or do not explain the patient's symptoms , physical examination alone has low specificity. Inaccuracy in physical diagnosis necessitated the use of radiographic imaging, such as voiding cystourethrography, evacuation proctography, cystocolporectography, and peritoneography. However, patient discomfort, complexity, invasiveness, radiation exposure, and relative lack of understanding of detailed anatomy and pathophysiology of pelvic prolapse and relaxation have resulted in relatively sparse use of these procedures. MRI , especially with the advent of rapid T2-weighted MR imaging sequences, has emerged as the imaging modality of choice for the evaluation and staging of pelvic floor dysfunction and preoperative planning. MRI allows for very quick, efficient, detailed, three-dimensional conceptualization, and reproducible evaluation of pelvic organ prolapse and pelvic floor relaxation. Rapid T2-weighted MR sequences allow images to be obtained in two ways, either by obtaining a series of images covering the entire pelvis (static imaging) or repetitively in one plane while the patient is straining (dynamic imaging). Dynamic imaging is usually necessary to demonstrate pelvic organ prolapse, which may be obvious only when abdominal pressure is increased. In addition, postoperative MR imaging can be done to assess pelvic floor integrity in the postoperative patient with persistent or recurrent symptoms.

Treatment of pelvic floor weakness depends on the patient's symptoms and the stage and compartments involved in the prolapse. Despite excellent operative treatment, symptoms recur in 10-30% of patients, and the cause of the problem often involves compartments of the pelvic floor that were not repaired initially.

References:

1. Pannu HK. Dynamic MR Imaging of Female Organ Prolapse. Radiologic Clinics of North America . 2003; 41(2): 409-23.
2. JR Fielding. Practical MR Imaging of Female Pelvic Floor Weakness. RadioGraphics . 2002; 22: 295-304.
3. De Almeida FG, Rodriguez LV , and S Raz . Magnetic Resonance Imaging in the Diagnosis of Pelvic floor Disorders. International Brazilian Journal of Urology. 2002; 28: 553-9.
4. Barbaric ZL, Marumoto AK , S Raz . Magnetic Resonance Imaging of the Perineum and Pelvic Floor. Topics in Magnetic Resonance Imaging. 2001; 12(2) 83-92.
5. Pannu HK, Kaufman HS, et al. Dynamic MR Imaging of Pelvic Organ Prolapse: Spectrum of Abnormalities . RadioGraphics . 2000; 20:1567–1582.