Note: This copy is for your personal non-commercial use only. To order presentation-ready copies for distribution to your colleagues or clients, contact us at www.rsna.org/rsnarights. WOMEN’S IMAGING 1417 MR Imaging–based Assessment of the Female Pelvic Floor1 Laura García del Salto, MD Jaime de Miguel Criado, MD Pelvic floor weakness is a functional condition that affects the ana- Luis Felipe Aguilera del Hoyo, MD tomic structures supporting the pelvic organs: fasciae, ligaments, Leticia Gutiérrez Velasco, MD and muscles. It is a prevalent disorder among people older than Patricia Fraga Rivas, MD 50 years, especially women, and may substantially diminish their Marcos Manzano Paradela, MD quality of life. Many complex causes of pelvic floor weakness have María Isabel Díez Pérez de las Vacas, been described, but the greatest risk factors are aging and female MD sex. Pelvic floor weakness can provoke a wide range of symptoms, Ana Gloria Marco Sanz, MD including pain, urinary and fecal incontinence, constipation, dif- Eduardo Fraile Moreno, MD, PhD ficulty in voiding, a sense of pressure, and sexual dysfunction. When the condition is diagnosed solely on the basis of physical and clini- Abbreviations: FIESTA = fast imaging em- cal examination, the compartments involved and the site of pro- ploying steady-state acquisition, MPL = midpu- bic line, PCL = pubococcygeal line lapse are frequently misidentified. Such errors contribute to a high number of failed interventions. Magnetic resonance (MR) imaging, RadioGraphics 2014; 34:1417–1439 which allows visualization of all three compartments, has proved a Published online 10.1148/rg.345140137 reliable technique for accurate diagnosis, especially when involve- Content Codes: ment of multiple compartments is suspected. MR imaging allows 1From the Department of Radiology, Central Ra- precise evaluation of ligaments, muscles, and pelvic organs and diodiagnostic Unit, Hospital del Henares, c/Ma- provides accurate information for appropriate surgical treatment. rie Curie s/n, 28822 Coslada, Spain (L.G.d.S., J.d.M.C., L.F.A.d.H., L.G.V., P.F.R., M.M.P., Moreover, dynamic MR imaging with steady-state sequences en- M.I.D.P.d.l.V., A.G.M.S.); and Central Radiodi- ables the evaluation of functional disorders of the pelvic floor. The agnostic Unit, Hospital Infanta Sofía, San Sebas- tián de los Reyes, Spain (E.F.M.). Presented as authors review the pelvic floor anatomy, describe the MR imaging an education exhibit at the 2011 RSNA Annual protocol used in their institutions, survey common MR imaging Meeting. Received February 2, 2012; revision findings in the presence of pelvic floor weakness, and highlight key requested March 6; final revision received April 3, 2014; accepted May 1. For this journal-based details that radiologists should provide surgeons to ensure effective SA-CME activity, the authors, editor, and re- treatment and improved outcomes. Online supplemental material is viewers have disclosed no relevant relationships. Address correspondence to L.G.d.S. (e-mail: available for this article. [email protected]). ©RSNA, 2014 • radiographics.rsna.org SA-CME LEARNING OBJECTIVES After completing this journal-based SA- CME activity, participants will be able to: Introduction ■■Describe the normal anatomy of the Pelvic floor weakness refers to a spectrum of functional disorders female pelvic floor and recognize the main MR imaging features of pelvic floor caused by impairment of the ligaments, fasciae, and muscles that sup- weakness. port the pelvic organs. Such disorders include urinary and fecal incon- ■■Discuss the role of MR imaging, espe- tinence, obstructed defecation, and pelvic organ prolapse. cially dynamic sequences, in the evalu- Pelvic floor weakness is prevalent and debilitating, substantially ation and management of pelvic floor diminishing the quality of life of those whom it affects. Approxi- weakness. mately 50% of women older than 50 years are affected by this condi- ■■Describe the MR imaging protocols tion worldwide, with a direct annual cost of $12 billion (1–3). In the used in evaluating pelvic floor weakness and in MR defecography. United States, disorders of the pelvic floor affect 23.7% of women See www.rsna.org/education/search/RG. (4), and prolapse is one of the most common indications for gyne- cologic surgery (5). In developing countries, the prevalence of pelvic organ prolapse is 19.7%, that of urinary incontinence is 28.7%, and that of fecal incontinence is 7% (6). Scan this code for access to supple- mental material on our website. 1418 September-October 2014 radiographics.rsna.org Figure 1. Schematic in the midsag- ittal plane shows the three functional anatomic compartments of the fe- male pelvis and the most important pathologic conditions that may occur in each: the anterior compartment (red), containing the bladder (B) and urethra (U); the middle com- partment (blue), containing the uterus (Ut), cervix, and vagina (V); and the posterior compartment (green), containing the anus, anal canal, rectum (R), and sigmoid colon. A fourth “virtual” compart- ment called the cul-de-sac (violet) is also shown. Note that the puborec- talis muscle surrounds the bladder neck, vagina, and rectum. PS = pubic symphysis. Pelvic organ prolapse and pelvic floor relax- incontinence and 80% of patients with utero- ation are related and often coexistent compo- vaginal prolapse had symptoms of obstructed nents of pelvic floor weakness but must be dif- defecation. In another study of patients with ferentiated. Pelvic organ prolapse is the abnormal defecatory disorders, dynamic cystocolpoproc- descent of a pelvic organ through the hiatus tography showed a cystocele in 71% of the pa- beneath it. This condition may affect the blad- tients, hypermobility of the bladder neck in 65% der (cystocele), vagina (vaginal prolapse), uterus of the patients, and a vaginal vault prolapse of (uterine prolapse), mesenteric fat (peritoneocele), more than 50% in 35% of the patients (11). small intestine, or sigmoid colon (sigmoidocele). A standardized system for assessing and doc- In pelvic floor relaxation, active and passive sup- umenting pelvic organ prolapse with a physical porting structures within the pelvic floor become examination, the pelvic organ prolapse quanti- weakened and ineffective, with resultant exces- fication (POP-Q) system, was proposed by the sive descent and widening of the entire pelvic International Continence Society in 1996 (12). floor during rest and/or evacuation, regardless of In this system, the descent of each compart- whether prolapse is present (7). ment is measured by using the vaginal hymen Many causes of pelvic floor weakness have as a reference line while the patient is in the li- been described, including multiparity, advanced thotomy position and is performing the Valsalva age, pregnancy, obesity, menopause, connective maneuver (13). Although this clinical grading tissue disorders, smoking, chronic obstructive system is widely accepted, it often leads to un- pulmonary disease, and conditions resulting in derestimation of the number of compartments a chronic increase in intraabdominal pressure affected. Moreover, failure to recognize prolapse (8). The greatest risk factors are aging and fe- in a substantial number of patients by using this male sex. approach contributes to high rates of therapeu- Pelvic floor weakness can provoke a wide tic failure (11). Several imaging techniques may range of symptoms, including pain, urinary and be used as adjuncts to physical examination. fecal incontinence, constipation, difficulty in Traditional imaging procedures (eg, urody- voiding, a sense of pressure, and sexual dysfunc- namic study, voiding cystourethrography, and tion. Symptoms are observed in 10%–20% of fluoroscopic cystocolpodefecography) remain women with pelvic prolapse and depend on the practical and cost-effective methods for evaluat- compartment involved. Because pelvic weak- ing uncomplicated anorectal and pelvic dysfunc- ness often involves multiple compartments, tion. Over the past decade, magnetic resonance symptoms may occur in various combinations (MR) imaging with dynamic sequences has (9). According to study results reported by Rush been proven accurate and reliable for identifying et al (10), 50% of patients with urinary stress pelvic floor weakness, especially when multiple RG • Volume 34 Number 5 García del Salto et al 1419 Figure 2. Schematic in the coronal plane at the level of the vagina (V) depicts the three levels of pelvic floor support: the endopelvic fascia, the pelvic diaphragm (levator ani level), and the urogenital diaphragm. B = bladder, BC = bulbocaverno- sus muscle, F = femur, I = iliacus muscle, IOM = internal obturator muscle, Is = ischial ramus, PB = puborectalis muscle, PC = pubococ- cygeus muscle, UT = uterus. compartments are involved, because it allows all Endopelvic Fascia three compartments to be visualized simultane- The urethral ligaments and perineal body are ously. In addition, ultrasonography (US) has the only components of the endopelvic fascia emerged in the past several years as an impor- and ligaments that are directly depicted on MR tant diagnostic method. images obtained with standard sequences. Dam- The next section of this article provides an age to other supporting structures within the overview of the normal female pelvic floor anat- pelvic floor can only be inferred from the pres- omy, fundamental knowledge for the accurate ence of secondary signs and abnormal descent and comprehensive interpretation of