PDF-843.pdf 397 ??? Vol. 9 | No. 1 | Winter 2012 |U R O LO G Y J O U R N A L MRI in Stress Urinary Incontinence Endovaginal MRI With an Intracavitary Coil and Dynamic Pelvic MRI Nuri Tasali,1 Rahmi Cubuk,1 Orhun Sinanoğlu,2 Kemal Sahin,1 Bulent Saydam3 Purpose: To evaluate both morphology of the urethra and its supporting struc- Materials and Methods: - cording to the different layers of the urethra, the degree of distortion in the pe- riurethral, paraurethral, and pubourethral ligaments, the vesicourethral angle, the also evaluated according to the number of deliveries and degree of the bladder neck prolapsus. Results: the urethra between the two groups (P - ourethral ligament distortion (P P the number of deliveries and the degree of the bladder neck prolapsus (P Conclusion: - dysfunction, such as vesicourethral angle increase and pubourethral ligament dis- Keywords: urethra, stress urinary incontinence, magnetic resonance imaging, women Corresponding Author: Orhun Sinanoglu, MD Department of Urol- ogy, Maltepe University, Feyzullah Caddesi, No.39, Maltepe, 34843, Istanbul, Turkey Tel: +90 533 658 6922 Fax: +90 216 383 0270 E-mail: orhundr@hotmail. com Received January 2011 Accepted July 2011 1 Department of Radiol- ogy, Maltepe University, Istanbul, Turkey 2 Department of Urology, Maltepe University, Istan- bul, Turkey 3 Department of Radiol- ogy, Fatih Sultan Mehmet Teaching Hospital, Istan- bul, Turkey Female Urology 398 | Female Urology INTRODUCTION Sinvoluntary voiding, which results in social and hygienic problems.(1) obesity, pregnancy, and vaginal delivery can lead to urinary incontinence by weakening the support on the urethra.(2-4) stability and restoring the functions of urethral sup- porting structures. The treatment options vary from - niques, depending on the severity of structural ab- normalities. Stress urinary incontinence has been linked to unequal urethral walls mobility, urethral instability,(5) and weakness in the pelvic supporting structures.(6,7) The comprehension of the normal disposition of the ligaments and anatomic defects in the suspensory system is essential because these are the surgically treatable factors in patients with (8) the urethra in women remains unclear as this area - mists and surgeons. continence mechanism considered the urethra and underlying structures to function as a combined mechanism.(6,7) Furthermore, precise imaging of the urethra and its supporting structures is very im- portant for treatment selection.(6) - both diagnosis and treatment decision.(11) Among imaging modalities, with its soft tissue resolution - alization of the pelvic structural alteration. Moreo- ver, endoluminal coils provide higher resolution and signal to noise ratio and can assess very small anatomical structures in detail.(6,12-15) Several studies have reported that endovaginal structures at rest and during Valsalva maneuver us- ing ultrafast sequences.(7,14,16-18) The aim of this study was to assess the convenience identify certain structural and functional abnormal- ities, such as vesicourethral angle increase and pu- MATERIALS AND METHODS Study Population - tinent controls who had never undergone surgery - cruited through urology and gynecology clinics. Study patients who met the above criteria were se- lected in a consecutive manner. Patients who were not married or did not accept the procedure were excluded. Stress urinary incontinence was diagnosed by a - - ments during cough and Valsalva maneuver. The caused by a sudden increase in intra-abdominal pressure during measurement with multi-channel urodynamic testing through an 8F micro-tip dual The control group were sent to department of radi- ology with suspicion of other gynecological benign diseases, including Bartholin cyst, diffuse vaginal The number of vaginal deliveries was documented - informed consent was obtained from each partici- 399Vol. 9 | No. 1 | Winter 2012 |U R O LO G Y J O U R N A L MRI in Stress Urinary Incontinence | Sinanoğlu et al MRI Technique Magnetic resonance imaging was performed fol- lowing at least four hours of fasting. The subjects were requested not to void at least for two hours by 1.5 Tesla magnet (25 mT/m: Magnetom Vi- sion Plus; Siemens, Erlangen, Germany) using connection between the urethra and coil, the coil - nal imaging planes using T2-weighted turbo spin- the bladder neck and extended to the external mea- tus level in planes perpendicular and parallel to the long axis of the urethra. Therefore, it was possible to visualize the entire length of the urethra. sagittal and coronal planes with true fast imaging - ed both at rest and during Valsalva maneuver. Ex- aminations were performed in supine position us- ing body coil and water resistant padding. Prior to the procedure, the subjects were informed about participants who were unable to produce enough strain, the sessions were repeated several times in order to achieve similar level of strain among sub- jects. During the sessions with 9-second duration, we obtained 6 slices in each plane. Measurements performed the assessments based on predetermined levels. These levels were determined based on the reference points reported by Kim and colleagues.(7) The straight and smooth muscle of the mucosa and submucosa layers were separately measured using predetermined levels. The supporting ligaments of the urethra were considered normal if they preserved their continuity throughout their entire length. The bending of the ligaments, the changes in signal intensity, and focal defects were consid- ered as the distortion of the ligament. The vesicourethral angle was assessed using sag- through the long axis of the urethra and one paral- lel to the bladder base, and the intersection of these lines determined the vesicourethral angle. We also used the sagittal images to measure the dimension of the retropubic space from the posterior wall of the symphysis pubis to the anterior urethral wall. The thickness of the two branches of the puborec- images. The mean muscle thickness was calculated from the thickness of the branches of the puborec- tal muscle measured at 4 and 8 o’clock radiuses using axial images. The degree of the bladder neck prolapsus in cases diagnosis of the bladder neck prolapsus was made - bis. The pubococcygeal line that determines the - nects the lower corner of symphysis pubis and left obtained during rest (Figure 1). The degree of pro- distance between the pubococcygeal line and infe- riorly extending bladder neck (mild to moderate: 1 - pendent radiologists (N.T. and K.S.), who were - gists had different interpretations of an image, the 400 | Statistical Analysis group, we used student’s t test to assess the differ- ences in the thickness of each layer of the urethra, vesicourethral angle, dimension of the retropubic space, and thickness of the puborectal muscle. - tion in periurethral, paraurethral, and pubourethral between the number of deliveries and degree of the bladder neck prolapsus was determined by Fis- cher’s Exact’s test. P - RESULTS was 49 years (range, 33 to 66 years) and 43.5 years (range, 38 to 53 years), respectively. The mean number of vaginal deliveries was 3.5 in patients Table 1 shows the mean thickness of each layer of group. The thickness of three layers of the urethra particularly in the striated muscle layer of patients P Table 1; Figure 2). More distortion of the pubourethral ligament was - trol group (P differences in the distortion of the periurethral and paraurethral ligaments between the two groups (P P = - garding the dimension of the retropubic space and thickness of the puborectal muscle (P 3; Figure 4). Bladder prolapsus was observed in all the subjects - Female Urology Figure 1. The bladder neck is visualized on top of the pubocoxy- geal line in a patient with stress urinary incontinence at rest. Figure 2. Thinning of the striated muscle of the urethra in a pa- tient with stress urinary incontinence at T2-weighted image in axial plane, which was obtained by using endovaginal coil. Figure 3. Normal urethral supporting ligaments. 401Vol. 9 | No. 1 | Winter 2012 |U R O LO G Y J O U R N A L in 19 patients and advanced in 6 patients (Figure the degree of the bladder prolapsus and number of P Table 4). DISCUSSION - - lection.(15) patient management.(19) Magnetic resonance imag- - changed clinical management in 41.6% of patients - bles visualization of the urethra and its supporting during Valsalva maneuver using fast sequences. (6,7,14,16,18) - sic muscles and supporting ligaments between pa- (7,12,17) These studies also reported that in patients with layers could be thin. The endovaginal coil was not only able to visualize the urethra throughout its whole length, but to evaluate the striated, smooth muscle, mucosa, and submucosa as well.(7,12,17) our study, the striated urethral muscles were sig- control group. association between the urethral sphincter anato- reported that a smaller striated urogenital sphincter (21) thickness of the urethral smooth muscle, mucosa, and submucosa layers between the two groups. urethra participate in the mechanism of inconti- nence. position or location of the urethral suporting liga- as detailed understanding of the normal continence MRI in Stress Urinary Incontinence | Sinanoğlu et al Figure 4. Asymmetrical thinning of the left puborectal sling in a patient with stress urinary incontinence. Figure 5. During Valsalva maneuver, the bladder neck can be identified below the puborectal line and the urethra becomes horizontally oriented distal to the pubic bone in a patient with stress urinary incontinence (T2-weighted sagittal image). 402 | underlying incontinence process.(19) Our study shows that distortion of pubourethral the urethral supporting ligaments, the pubourethral ligament distortion plays an important role in the - tion of the periurethral and paraurethral ligaments between two groups. The vesicourethral angle and dimension of ret- ropubic space are closely related to the urethral (22) The mean dimension of the retropubic space was larger in our might be the expansion of endovaginal coil balloon with air that caused smaller measurements for the dimension of retropubic space. A defect in ham- mock structure consisting of anterior vaginal wall and pubourethral ligaments was shown in several studies. reports, as the grade of distortion in the puboure- - mean thickness of the puborectal muscle and num- the control group. The two groups did not differ for the degree of the bladder prolapsus determined by the number of vaginal deliveries and thickness of puborectal muscle are not individual determinants demonstrate that the most determining parameter layers, particularly in the striated muscle layer. One of the limitations of our study is the fact that the assessments were performed in the supine po- Female Urology Table 1. The thickness of the urethral layers in patients with stress urinary incontinence compared to controls Urethral layers thickness (mean ± SD)†, mm Patients with stress urinary incontinence (n = 25) Control group (n = 8) 95% Confidence interval p* Striated muscle 1.7 ± 0.2 2.3 + 0.2 - 0.80 to - 0.40 .000 Smooth muscle 3.1 ± 0.2 3.3 + 0.2 - 0.56 to - 0.06 .024 Mucosa and Submucosa 2.5 ± 0.2 2.7 + 0.1 - 0.31 to - 0.05 .009 †SD indicates standard deviation. *P < .05 is significant. Table 2. Distribution of the distortion in the urethral supporting ligaments; comparison of patients with urinary inconti- nence and asymptomatic controls. Distortion in the supporting ligaments of the urethra, n (%) Patients with stress urinary incontinence (n = 25) Control group (n = 8) p* Periurethral ligaments 14 (56.0) 3 (37.5) > .05 Paraurethral ligaments 25 (100) 6 (75.0) > .05 Pubourethral ligaments 15 (60.0) 1 (12.5) .024 *P < .05 is significant. 403Vol. 9 | No. 1 | Winter 2012 |U R O LO G Y J O U R N A L sition. As compared to normal anatomical posi- tion, the investigations performed in supine posi- tion do not allow to assess the dynamic changes in the urethra and its supporting structures result- ing from the changes of intra-abdominal pressure. due to gravity and increased intra-abdominal pressure in vertical or standing positions during - - cept posterior urethrovesical angle were reported to be stable between supine and sitting positions. (24) Other investigators showed that assessments in supine position after maximum strain were more reliable.(25) Another limitation of our study comes from the use of endovaginal coil technique, which sup- ports the anterior wall of the vagina. The use of this coil technique can displace the vaginal walls laterally and visualize rather small defects in these assess the fascia and muscle structures accurately with high spatial resolution still presents as an ad- vantage. CONCLUSION provides complementary information and allows - functions. However, we accept that the utility of - cordance with comprehensive studies, which may assess the structural abnormalities directly related CONFLICT OF INTEREST None declared. MRI in Stress Urinary Incontinence | Sinanoğlu et al Table 3. Comparison of the patients with urinary incontinence and asymptomatic controls regarding the mean values of vesicourethral angle, retropubic space, and puborectal muscle thickness Patients with stress urinary incontinence (n = 25) Control group (n = 8) 95% Confidence interval p* Vesicourethral angle (mean ± SD)† 146 ± 5.05 136 ± 3.84 5.26 to 13.23 .000 Retropubic space (mean ± SD), mm 4.46 ± 0.79 3.28 ± 0.83 0.43 to 1.909 > .05 Puborectal muscle thickness (mean ± SD), mm 3.676 ± 0.63 3.688 ± 0.65 - 0.53 to - 0.51 > .05 †SD indicates standard deviation. *P < .05 is significant. Table 4. Comparison of the degree of the bladder prolapsus and number of deliveries in patients with stress urinary incontinence. Number of deliveries Degree of the bladder prolapsus Mild to Moderate, n (%) Advanced, n (%) Total p* 1 to 3 11 (78.6) 3 (21.4) 14 (100) > .05≥ 4 8 (72.7) 3 (27.3) 11 (100) Total 19 (76.0) 6 (24.0) 25 (100) *P < .05 is significant. 404 | REFERENCES 1. Abrams P, Blaivas JG, Stanton SL, Andersen JT. The stand- ardisation of terminology of lower urinary tract function. The International Continence Society Committee on Stand- ardisation of Terminology. Scand J Urol Nephrol Suppl. 1988;114:5-19. 2. Herzog AR, Fultz NH. Prevalence and incidence of urinary incontinence in community-dwelling populations. J Am Geriatr Soc. 1990;38:273-81. 3. Diokno AC, Brock BM, Brown MB, Herzog AR. Prevalence of urinary incontinence and other urological symptoms in the noninstitutionalized elderly. J Urol. 1986;136:1022-5. 4. Herzog AR, Diokno AC, Fultz NH. Urinary incontinence: medical and psychosocial aspects. Annu Rev Gerontol Geri- atr. 1989;9:74-119. 5. Mostwin JL, Yang A, Sanders R, Genadry R. Radiography, sonography, and magnetic resonance imaging for stress incontinence. Contributions, uses, and limitations. Urol Clin North Am. 1995;22:539-49. 6. Stoker J, Rociu E, Bosch JL, et al. High-resolution endovagi- nal MR imaging in stress urinary incontinence. Eur Radiol. 2003;13:2031-7. 7. Kim JK, Kim YJ, Choo MS, Cho KS. The urethra and its sup- porting structures in women with stress urinary inconti- nence: MR imaging using an endovaginal coil. AJR Am J Roentgenol. 2003;180:1037-44. 8. Klutke C, Golomb J, Barbaric Z, Raz S. The anatomy of stress incontinence: magnetic resonance imaging of the female bladder neck and urethra. J Urol. 1990;143:563-6. 9. Vazzoler N, Soulie M, Escourrou G, et al. Pubourethral liga- ments in women: anatomical and clinical aspects. Surg Ra- diol Anat. 2002;24:33-7. 10. Fauconnier A, Delmas V, Lassau JP, Boccon-Gibod L. Ventral tethering of the vagina and its role in the kinetics of urethra and bladder-neck straining. Surg Radiol Anat. 1996;18:81-7. 11. DeLancey JO, Trowbridge ER, Miller JM, et al. Stress urinary incontinence: relative importance of urethral support and urethral closure pressure. J Urol. 2008;179:2286-90; discus- sion 90. 12. Tan IL, Stoker J, Zwamborn AW, Entius KA, Calame JJ, Lam- eris JS. Female pelvic floor: endovaginal MR imaging of nor- mal anatomy. Radiology. 1998;206:777-83. 13. Goh V, Halligan S, Kaplan G, Healy JC, Bartram CI. Dynamic MR imaging of the pelvic floor in asymptomatic subjects. AJR Am J Roentgenol. 2000;174:661-6. Female Urology 14. Macura KJ, Genadry RR. Female urinary incontinence: pathophysiology, methods of evaluation and role of MR im- aging. Abdom Imaging. 2008;33:371-80. 15. Tunn R, DeLancey JO, Quint EE. Visibility of pelvic organ support system structures in magnetic resonance im- ages without an endovaginal coil. Am J Obstet Gynecol. 2001;184:1156-63. 16. Prando A. The urethra and its supporting structures in wom- en with stress urinary incontinence: MR imaging using an endovaginal coil. Int Braz J Urol. 2003;29:174-5. 17. Aronson MP, Bates SM, Jacoby AF, Chelmow D, Sant GR. Periurethral and paravaginal anatomy: an endovaginal magnetic resonance imaging study. Am J Obstet Gynecol. 1995;173:1702-8; discussion 8-10. 18. Unterweger M, Marincek B, Gottstein-Aalame N, et al. Ultra- fast MR imaging of the pelvic floor. AJR Am J Roentgenol. 2001;176:959-63. 19. el-Sayed RF, Morsy MM, el-Mashed SM, Abdel-Azim MS. Anatomy of the urethral supporting ligaments defined by dissection, histology, and MRI of female cadavers and MRI of healthy nulliparous women. AJR Am J Roentgenol. 2007;189:1145-57. 20. El Sayed R, Fielding J, El Mashed S, Morsy M, El Azim M. Pre- operative and postoperative magnetic resonance imaging of female pelvic floor dysfunction: correlation with clinical findings. J Women’s Imaging 2005;7:163-80. 21. Morgan DM, Umek W, Guire K, Morgan HK, Garabrant A, DeLancey JO. Urethral sphincter morphology and function with and without stress incontinence. J Urol. 2009;182:203- 9. 22. Macura KJ, Genadry RR, Bluemke DA. MR imaging of the female urethra and supporting ligaments in assessment of urinary incontinence: spectrum of abnormalities. Radio- graphics. 2006;26:1135-49. 23. El Sayed RF, El Mashed S, Farag A, Morsy MM, Abdel Azim MS. Pelvic floor dysfunction: assessment with combined analysis of static and dynamic MR imaging findings. Radiol- ogy. 2008;248:518-30. 24. Fielding JR. Practical MR imaging of female pelvic floor weakness. Radiographics. 2002;22:295-304. 25. Bertschinger KM, Hetzer FH, Roos JE, Treiber K, Marincek B, Hilfiker PR. Dynamic MR imaging of the pelvic floor per- formed with patient sitting in an open-magnet unit versus with patient supine in a closed-magnet unit. Radiology. 2002;223:501-8.