IMAGING

Pelvic floor dysfunction: assessment with combined analysis of static and dynamic MR imaging findings
El Sayed RF, El Mashed S, Farag A, Morsy MM, Abdel Azim MS
Department of Radiology, Faculty of Medicine, Cairo University, Kaser El Aini Street, Cairo, Egypt
Radiology. 2008; 248: 518-30

• Purpose: To prospectively analyze static and dynamic magnetic resonance (MR) images simultaneously to determine whether stress urinary incontinence (SUI), pelvic organ prolapse (POP), and anal incontinence are associated with specific pelvic floor abnormalities.
• Materials and Methods: This study had institutional review board approval, and informed consent was obtained from all participants. There were 59 women: 15 nulliparous study control women (mean age, 25.6 years) and 44 patients (mean age, 43.4 years), who were divided into four groups according to chief symptom. Static T2-weighted turbo spin-echo images were used in evaluating structural derangements; functional dynamic (cine) balanced fast-field echo images were used in detecting functional abnormalities and recording five measurements of supporting structures. Findings on both types of MR images were analyzed together to determine the predominant defect. Analysis of variance and the Bonferroni t test were used to compare groups.
• Results: In the four patient groups, POP was associated with levator muscle weakness in 16 (47%) of 34 patients, with level I and II fascial defects in seven (21%) of 34 patients, and with both defects in 11 (32%) of 34 patients. SUI was associated with defects of the urethral supporting structures in 25 (86%) of 29 patients but was not associated with bladder neck descent. Levator muscle weakness may lead to anal incontinence in the absence of anal sphincter defects. Measurements of supporting structures were significant (P < 0.05) in the identification of pelvic floor laxity.
• Conclusion: Combined analysis of static and dynamic MR images of patients with pelvic floor dysfunction allowed identification of certain structural abnormalities with specific dysfunctions.
  
  
• Editorial Comment
  Multifactorial dysfunction contributes to the etiology of pelvic organ prolapse: a) weakness, thinning and /or tearing of levator ani musculature; b) laxity and/or tearing of the endopelvic fascia and c) laxity and /or tearing of apical supporting ligaments of the vagina. Both static and dynamic magnetic resonance imaging studies have been shown to be useful for the evaluation of female pelvic floor dysfunction an entity that usually encompasses stress urinary incontinence, pelvic organ prolapse and anal incontinence. Although these techniques have been used more frequently in recent years, determination of precise anatomic causes of these clinical abnormalities are still not clear. The authors present the results of a prospective study performed in 59 women (15 volunteer nulliparous women-control group and in 44 women with a parity range of 0 to 7, and pelvic floor dysfunction). Combined analysis of static and dynamic MR images of the pelvic floor reveals that it is possible to differentiate whether prolapse is due to defects in the endopelvic fascia, to levator muscle weakness, or to abnormalities in both fascia and muscles. Another important conclusion: a) stress urinary incontinence is associated with structural defects in the urethral supporting structures rather than with bladder neck descent and b) in the absence of an anal sphincter defect, anal incontinence is associated with marked levator muscle weakness.

Dr. Adilson Prando
Chief, Department of Radiology and
Diagnostic Imaging, Vera Cruz Hospital
Campinas, São Paulo, Brazil
E-mail: adilson.prando@gmail.com