Pelvic floor descent in women: dynamic evaluation with fast MR imaging and cinematic display

The authors present a new method for assessing pelvic prolapse with dynamic fast magnetic resonance (MR) imaging. Twenty-six women with signs and symptoms suggesting pelvic prolapse and 16 control subjects were studied with a series of fast (6-12-second) MR images. Sagittal and coronal images were obtained with graded increase in voluntary pelvic strain, allowing for dynamic display and quantification of the pelvic prolapse process. The distance from the pubococcygeal line was used as an internal reference for measurement of descent in the maximal strain position. With use of control results for normal limit values, prolapse involving the anterior pelvic compartment (cystocele), the middle compartment (vaginal prolapse, uterine prolapse, and enterocele), and the posterior compartment (rectocele) was easily demonstrated. Significant differences between control subjects and patients with prolapse were seen at maximal strain but not in the relaxed state. Quantification of the pelvic descent process with use of fast MR imaging may be of value in surgical planning and postsurgical follow-up.     

Diagnostic radiology of the pelvis. Prostate cancer, bladder cancer, and incontinence

Prostate cancer, bladder cancer, and pelvic floor weakness are among the most common diseases of the pelvis. Cardinal symptoms include painless macrohematuria in bladder cancer and urinary and fecal incontinence in pelvic floor weakness. Suspicion of prostate cancer currently is most frequently raised when the serum concentration of prostate-specific antigen is pathologically elevated. Besides extensive clinical and invasive diagnosis, clinical imaging is frequently applied for the localization, locoregional staging, and diagnosis of recurrence of prostate cancer and invasive bladder cancer, and in clinically difficult cases of cystocele, enterocele, rectocele, descensus or prolapse of vagina, uterus, and rectum, and rectal intussusception. Magnetic resonance imaging with T2-weighted TSE or FSE images in several planes combined with either axial, T1-weighted images and MR spectroscopy for the prostate, dynamic contrast-enhanced T1-weighted images for the urinary bladder, or dynamic T2-weighted functional images for pelvic floor incontinence are particularly well suited as clinical imaging methods.     

Radiologische Beckendiagnostik

Prostate cancer, bladder cancer, and pelvic floor weakness are among the most common diseases of the pelvis. Cardinal symptoms include painless macrohematuria in bladder cancer and urinary and fecal incontinence in pelvic floor weakness. Suspicion of prostate cancer currently is most frequently raised when the serum concentration of prostate-specific antigen is pathologically elevated. Besides extensive clinical and invasive diagnosis, clinical imaging is frequently applied for the localization, locoregional staging, and diagnosis of recurrence of prostate cancer and invasive bladder cancer, and in clinically difficult cases of cystocele, enterocele, rectocele, descensus or prolapse of vagina, uterus, and rectum, and rectal intussusception. Magnetic resonance imaging with T2-weighted TSE or FSE images in several planes combined with either axial, T1-weighted images and MR spectroscopy for the prostate, dynamic contrast-enhanced T1-weighted images for the urinary bladder, or dynamic T2-weighted functional images for pelvic floor incontinence are particularly well suited as clinical imaging methods.     

Ultrafast MR imaging of the pelvic floor

OBJECTIVE: The aim of this study was to compare pelvic floor anatomy and laxity at rest and on straining (Valsalva's maneuver) using dynamic ultrafast MR imaging in women who were continent versus those with stress incontinence differing in obstetric history. MATERIALS AND METHODS: Thirty continent women were divided into three equal groups (nulliparous, previous cesarean delivery, previous vaginal delivery) and compared with 10 women with stress-incontinence with a history of at least one vaginal delivery. MR imaging of the pelvic floor at rest and on maximal strain was performed, using axial T2-weighted fast spin-echo images followed by sagittal ultrafast T2-weighted single-shot fast spin-echo sequences. Mean population age (age range, 22-45 years; mean +/- SD, 36 +/- 5.4 years), was similar in the four groups, as was parity in the three parous groups. RESULTS: Mean distances between the bladder floor and pubococcygeal line at rest did not differ between the four groups. On straining, bladder floor descent was 1.1 +/- 0.9, 1.0 +/- 1.1, and 1.9 +/- 0.9 cm in continent nulliparous, cesarean delivery, and vaginal delivery women, respectively, versus 3.2 +/- 1.0 cm in incontinent women (p = 0.0005). Cervical descent was greater in incontinent versus nulliparous women (p = 0.0019). Bladder floor descent was greater in the continent vaginal delivery group than in continent cesarean delivery control patients (p = 0.04). In patients with stress incontinence, symptoms did not correlate with amplitude of descent. The right levator muscle was thinner overall than the left, regardless of frequency direction (p = 0.001). CONCLUSION: Ultrafast MR imaging using the T2-weighted single-shot fast spin-echo sequence allows dynamic evaluation of the pelvic compartments at maximal strain with no need for contrast medium. Pelvic floor laxity and supporting fascia abnormalities were most common in patients with stress incontinence followed by continent women with a history of vaginal delivery. The results are therefore compatible with the hypothesis of vaginal delivery as a contributory factor to stress incontinence in older parous women.     

MR imaging of the female pelvic floor in the supine and upright positions

The goal of this study was to determine whether a .5-T open configuration magnet system could be used to evaluate the female pelvic floor support structures and their functional changes in the upright and supine positions. We evaluated five normal volunteers with full bladders in the supine and sitting positions. Multiple measurements were obtained, including distance between symphysis and urethra, bladder neck to fixed pubococcygeal line, and posterior urethrovesical angle. The pelvic floor was evaluated for integrity of the urethra, vagina, and supporting ligaments. High quality, interpretable images were obtained for all five patients in both positions. Most of the pelvic floor structures were stable, with the exception of the posterior urethrovesical angle, which increased in the sitting position. We conclude that the vertically open configuration magnet system shows promise for evaluation of the female pelvic floor, including urinary stress incontinence and prolapse.     

盆底功能性疾病的动态MRI研究

目的　评价盆底动态MRI形态学表现与盆底功能性疾病的相关性。资料与方法　采用Siemens 1.0T超导磁共振成像仪对 6 0例妇女进行MRI检查 ,将这些受试者分为两组 :30例为无症状健康志愿者和 30例为盆底功能性疾病患者。采用仰卧位使用梯度回波二维FLASHT1WI快速扫描序列获得屏气期间盆底横断面、冠状面和矢状面的静息和最大盆腔用力时MR影像。所有影像用于观测盆腔器官脱垂和盆底形态 ,比较两组间盆腔器官脱垂和盆底形态变化的程度。结果　盆腔器官脱垂常发生于多个部位 ,盆底功能性疾病患者发生频率较高 ,与健康受试者比较相差显著 :膀胱膨出 (P <0 .0 1) ,子宫颈脱垂 (P <0 .0 1) ,盆底疝 (P <0 .0 1) ,直肠连接异常下降 (P <0 .0 1) ,直肠膨出 (P <0 .0 1)和盆隔裂孔膨胀 (P <0 .0 1)。结论　盆底动态MRI可用于准确评价盆腔器官脱垂和盆底形态 ,盆底功能性疾病患者常出现整个盆底软弱 ,盆腔器官脱垂频繁发生于多个部位并伴随盆隔裂孔的显著膨胀     

静动态MRI在盆腔器官脱垂术前与术后中的应用

目的：探讨静动态 MRI 在盆腔器官脱垂(POP)术前诊断、术后疗效评价中的价值。方法经盆腔器官脱垂量化分度法(POP-Q)诊断为 POP 的患者29例,对照组为年龄、产次和体质量与之匹配的无症状志愿者12例,行静态和动态盆底 MRI 检查,观察盆底结构形态学变化,测量 POP 患者术前、术后及对照组动态 MRI 图像上各指标：膀胱下缘到耻尾线(PCL)的垂直距离(B-PCL)、子宫颈到 PCL 的垂直距离(U-PCL)、Douglas 窝到 PCL 的垂直距离(D-PCL)、耻骨直肠肌裂孔线(H 线)、盆底肌下降距离(M 线)、肛提肌裂孔面积(LHS)、肛提肌板角度(LPA)、髂尾肌角度(ICA)、尿道倾斜角(UA)。结果POP 患者术前 MRI 上诊断膀胱膨出19例,子宫脱垂28例,直肠膨出4例,Douglas 窝疝14例,盆底松弛29例,发现肛提肌缺陷27例,耻骨宫颈筋膜缺陷24例。POP 患者术前 B-PCL、U-PCL、D-PCL、H 线、M 线、LHS、LPA、ICA 及 UA 等测量值均大于对照组,其差异均有非常显著意义(P <0.01);21例 POP 术后患者中,MRI 发现9例盆腔器官位置恢复正常,12例仍有脱垂;8例网片植入患者术后 MRI 显示网片无移位;POP患者术后 B-PCL、U-PCL、D-PCL、UA 测量值较术前缩小,其差异有统计学意义(P <0.05)。结论静动态 MRI 可全面评价 POP术前、术后盆底形态和功能改变,检出隐匿的脱垂和术后残存。     

Dynamic MR imaging of pelvic organ prolapse: spectrum of abnormalities.

Pelvic organ prolapse is a relatively common condition in women that can have a significant impact on quality of life. Pelvic organ prolapse typically demonstrates multiple abnormalities and may involve the urethra, bladder, vaginal vault, rectum, and small bowel. Patients may present with pain, pressure, urinary and fecal incontinence, constipation, urinary retention, and defecatory dysfunction. Diagnosis is made primarily on the basis of findings at physical pelvic examination. Imaging is useful in patients in whom findings at physical examination are equivocal. Fluoroscopy, ultrasonography, and magnetic resonance (MR) imaging can be useful in evaluating pelvic organ prolapse. Advantages of MR imaging include lack of ionizing radiation, depiction of the soft tissues of the pelvic floor, and multiplanar imaging capability. Dynamic imaging is usually necessary to demonstrate pelvic organ prolapse, which may be obvious only when abdominal pressure is increased. Treatment is more likely to be successful if a survey of the entire pelvis is performed prior to therapy. Therapy is usually undertaken only in symptomatic patients. In all patients, imaging findings must be interpreted in conjunction with physical examination findings and the patient's symptoms.     

MR排便造影在后盆腔障碍性疾病中的评估价值

后盆腔障碍疾病是以肛直肠解剖和功能异常为主的一类盆底功能障碍性疾病,伴有便秘、便失禁等临床症状。MR排便造影是一种动态MR成像方法,可对后盆腔结构形态和运动功能异常情况直观显示,能够鉴别后盆腔障碍性疾病的类型并认识其发病原因,如直肠膨出、肠疝、盆腔器官脱垂和直肠套叠、脱垂等,同时对便失禁早期的肛直肠形态学和功能学异常改变的诊断有重要提示价值。     

Pelvic floor descent in females: comparative study of colpocystodefecography and dynamic fast MR imaging

The purpose of this study was to compare fast dynamic magnetic resonance imaging (MRI) with colpocystodefecography (CCD) in the evaluation of pelvic floor descent in women. Thirty-five women with clinical evidence of pelvic floor descent were studied. A fast single-shot MR sequence was performed in the supine position during pelvic floor relaxation and during maximal pelvic strain. On the same day, a dynamic CCD was performed with the patient seated on a stool-chair. The degree of descent of the bladder, vagina, and anorectal junction was evaluated as the vertical distance between the pubococcygeal line and the bladder base, the vaginal vault, and the anorectal junction, respectively. A bulge of more than 3 cm measured as the distance between the extended line of the anterior border of the anal canal and the tip of the rectocele was interpreted as a rectocele. MRI was compared with CCD during maximal pelvic strain (CCD 1) and during voiding and defecation (CCD II). CCD was considered as the gold standard. Compared with clinical examination, CCD I showed a larger number of involved compartments, except for the middle compartment. CCD II was superior to clinical examination in all cases. In comparison with CCD I and especially CCD II, MRI had a lower sensitivity, especially for the anterior and middle compartment. Even four enteroceles seen on CCD II were not detected by MRI. When CCD I and CCD II were compared, a cystocele, a vaginal vault prolapse, an enterocele, and a rectocele were more readily seen on CCD II than with CCD I. When compared with CCD, supine dynamic MRI is unreliable, especially in the anterior and middle compartment. Even in the detection of enteroceles CCD was superior to MRI. In general, the best results with MRI can be expected for evaluation of the rectum.     

Sectional depiction of the pelvic floor by CT, MR imaging and sheet plastination: computer-aided correlation and 3D model

The structures of the pelvic floor are clinically important but difficult to assess. To facilitate the understanding of the complicated pelvic floor anatomy on sectional images obtained by CT and MR imaging, and to make the representation more vivid, a computer-aided 3D model was created from a male and a female torso to develop a teaching tool. A male and a female cadaver torso were investigated by means of CT, MR imaging, and serial-section sheet plastination. A 3D reconstruction of the pelvic floor and adjacent structures was performed by fusion of CT and MR imaging data sets with sheet plastination sections. Corresponding sections from all three methods could be compared and visualized in their 3D context. Sheet plastination allows distinction of connective tissue, muscles, and pelvic organs down to a microscopic level. In combination with CT, MR imaging, and sheet plastination a 3D model of the pelvic floor offers a better understanding of the complex pelvic anatomy. This knowledge may be applied in the diagnostic imaging of urinary incontinence or prolapse and prior to prostate surgery. Received: 18 January 2000 Revised: 1 June 2000 Accepted: 6 June 2000     

MR defecography in patients with fecal incontinence: imaging findings and their effect on surgical management

PURPOSE: To retrospectively evaluate magnetic resonance (MR) defecography findings in patients with fecal incontinence who were evaluated for surgical treatment and to assess the influence of MR defecography on surgical therapy. MATERIALS AND METHODS: Institutional review board approval was obtained. Informed consent was waived; however, written informed consent for imaging was obtained. Fifty patients (44 women, six men; mean age, 61 years) with fecal incontinence were placed in a sitting position and underwent MR defecography performed with an open-configuration MR system. Midsagittal T1-weighted MR images were obtained at rest, at maximal contraction of the sphincter, and at defecation. Images were prospectively and retrospectively reviewed by two independent observers for a variety of findings. Interobserver agreement was analyzed by calculating kappa statistics. Prospective interpretation of MR defecography findings was used to influence surgical therapy, and retrospective interpretation was used for concomitant pelvic floor disorders. RESULTS: MR defecography revealed rectal descent of more than 6 cm (relative to the pubococcygeal line) in 47 (94%) of 50 patients. A bladder descent of more than 3 cm was present in 20 (40%) of 50 patients, and a vaginal vault descent of more than 3 cm was present in 19 (43%) of 44 women. Moreover, 17 (34%) anterior proctoceles, 16 (32%) enteroceles, and 10 (20%) rectal prolapses were noted. Interobserver agreement was good to excellent (kappa = 0.6-0.91) for image analysis results. MR defecography findings led to changes in the surgical approach in 22 (67%) of 33 patients who underwent surgery. CONCLUSION: MR defecography may demonstrate a variety of abnormal findings in patients who are considered candidates for surgical therapy for fecal incontinence, and the findings may influence the surgical treatment that is subsequently chosen. Supplemental material: http://radiology.rsnajnls.org/cgi/content/full/2402050648/DC1     

Dynamic MR imaging of the pelvic floor in asymptomatic subjects

OBJECTIVE: Dynamic MR imaging may be used as an alternative to dynamic cystoproctography for the evaluation of pelvic floor prolapse and configuration. MR criteria for normality are derived from proctographic studies because no large MR study of asymptomatic individuals has been performed. Our study aimed to define the normal range of dynamic pelvic MR appearances in a large group of asymptomatic individuals. SUBJECTS AND METHODS: Fifty healthy adult volunteers (25 men and 25 women; age range, 20-66 years; mean age, 34 years) were prospectively recruited and examined using dynamic MR imaging. All subjects were interviewed and established as healthy using a validated questionnaire. Axial, coronal, and sagittal MR imaging was performed at rest and during maximum pelvic strain using a static 1.0-T unit and a fast-field-echo sequence, providing 10 slices in 31 sec. Standardized measurements of pelvic configuration were taken, and rest and strain imaging were compared to determine the range of normal appearances. RESULTS: Three women developed a cystocele during maximum pelvic strain, two of whom also showed grade 1 uterocervical prolapse, which was also seen in another woman. Three men showed posterior pelvic floor descent in excess of 3 cm during straining. No rectocele, enterocele, rectal prolapse, or perineal hernia was seen in any subject. CONCLUSION: The normal range of pelvic organ descent in asymptomatic subjects seen on dynamic MR imaging included cystocele, uterocervical prolapse, and excessive anorectal junction descent. Although we encountered pelvic prolapse in seven volunteers, it was infrequent and low grade, suggesting that criteria for abnormality derived from proctography are generally applicable to MR imaging.     

Dynamic magnetic resonance imaging; reliability of assessment and correlation with clinical findings of pelvic organ prolapse

Introduction

Pelvic floor dysfunction and prolapse affect about 50% of women past middle age. Failure to recognize the complex set of pelvic floor defects in individuals leads to most postsurgical failures. Diagnosis and grading of pelvic floor dysfunction is primarily done by physical examination. Imaging does not have yet an established role in the investigation of prolapse, yet it is expected to play a role in preoperative planning identifying soft tissue abnormalities which will help avoiding recurrence.

Aim of the work

This is a prospective study targeted at defining the role of MRI in assessment of pelvic floor prolapse in females.

Methods

Dynamic and static MRI was performed in 40 female patients complaining of pelvic organ prolapse and/or stress urinary incontinence or fecal incontinence. Full history was taken and clinical examination performed and findings compared with MRI results.

Results

Good concordance was found between dynamic MRI and clinical examination in all three compartments, it was 82.5% in the anterior compartment, 80% in the posterior compartment, 85% in enteroceles and 65.0% in the middle compartment.

Conclusion

Dynamic MRI is expected to be a promising imaging tool and to play a larger role in the preoperative planning of pelvic organ prolapse in the near future.     

Imaging of the posterior pelvic floor

Disorders of the posterior pelvic floor are relatively common. The role of imaging in this field is increasing, especially in constipation, prolapse and anal incontinence, and currently imaging is an integral part of the investigation of these pelvic floor disorders. Evacuation proctography provides both structural and functional information for rectal voiding and prolapse. Dynamic MRI may be a valuable alternative as the pelvic floor muscles are visualised, and it is currently under evaluation. Endoluminal imaging is important in the management of anal incontinence. Both endosonography and endoanal MRI can be used for detection of anal sphincter defects. Endoanal MRI has the advantage of simultaneously evaluating external sphincter atrophy, which is an important predictive factor for the outcome of sphincter repair. Many aspects of constipation and prolapse remain incompletely understood and treatment is partly empirical; however, imaging has a central role in management to place patients into treatment-defined groups.     

Computed tomography evaluation of pelvic organ prolapse. Techniques and applications

OBJECTIVES: Pelvic organ prolapse is a common debilitating condition affecting women. Cross-sectional imaging with magnetic resonance imaging (MRI) depicts pelvic floor anatomy as well as organ prolapse and can complement or replace fluoroscopy. Occasionally, patients cannot tolerate MRI, but multiplanar visualization of pelvic floor soft tissue anatomy and organ prolapse is clinically desired. The objective of this study was to determine if computed tomography (CT) is a potential diagnostic technique in these specific situations for demonstrating organ prolapse and the pelvic floor. METHODS: Seven women (mean age: 63.5 years) with clinical pelvic organ prolapse were referred for CT of the pelvis from the gynecologic and surgical clinics from November 1998 to September 2001. The CT technique included the following: insufflation of rectal air, positive oral contrast, supine position with knees flexed, and imaging at rest and straining with a single-detector scan in 5 cases (slice thickness of 3 mm, table speed of 5 mm/s, 2-mm reconstruction interval) and a multidetector scan in 1 case (detector collimation of 1 mm, slice thickness of 1.25 mm, 1-mm reconstruction interval). Axial and 3-dimensional images were interpreted. RESULTS: Computed tomography demonstrated prolapse in 5 of 7 patients. At CT, cystocele was present in 2 of 7 patients, vault or cervical prolapse was present in 4 of 7, enterocele was present in 3 of 7, rectocele was present in 2 of 7, and levator abnormalities were present in 4 of 7. Surgery was performed in 3 of the 5 patients with positive CT findings, and prolapse was confirmed. Surgery was also performed in 1 patient with negative CT findings, and global prolapse was detected. CONCLUSIONS: Demonstration of pelvic organ prolapse and muscular pelvic floor abnormalities is feasible with CT if the patient strains adequately. In patients who cannot tolerate MRI, CT may be useful as an alternative diagnostic tool.     

MR-based three-dimensional modeling of the normal pelvic floor in women: quantification of muscle mass

OBJECTIVE: Our objective was to use a combination of axial MR source images and three-dimensional (3D) models to describe the anatomy of the normal pelvic floor in young nulliparous women and to measure the volume of the levator ani. SUBJECTS AND METHODS: Ten healthy nulliparous female volunteers (average age, 27 years) underwent T2-weighted MR imaging of the pelvis. Three-dimensional color-coded models of the pelvic bones and organs and the three major components of the levator ani--puborectalis, iliococcygeus, and coccygeus--were created. Source images were used to measure muscle width and signal intensity and to identify ligamentous structures. Using 3D models, we measured the volume of the levator ani, the angle of the levator plate, the posterior urethrovesical angle, and the distance of the bladder neck from the symphysis pubis and the pubococcygeal line. RESULTS: In all volunteers, the signal intensity of the puborectalis exceeded that of the obturator externus. The average volume of the levator ani was 46.6 ml, the average width of the levator hiatus was 41.7 mm, and the average posterior urethrovesical angle was 143.5 degrees. Vaginal shape in the volunteers followed no recognizable pattern. CONCLUSION: Muscle morphology, signal intensity, and volume is relatively uniform among healthy young women.     

Female pelvic organ prolapse: a comparison of triphasic dynamic MR imaging and triphasic fluoroscopic cystocolpoproctography

OBJECTIVE: This study compared dynamic MR imaging with fluoroscopic cystocolpoproctography for the detection and measurement of prolapse of pelvic organs. SUBJECTS AND METHODS: Ten patients underwent triphasic dynamic MR imaging and triphasic fluoroscopic cystocolpoproctography with identical amounts of contrast material to opacify the bladder, vagina, and rectum. The dynamic MR imaging procedure included cine-loop presentation. Each examination was analyzed to determine the presence and extent of prolapse of pelvic organs based on specific measurements. RESULTS: Both dynamic MR imaging and fluoroscopic cystocolpoproctography revealed 10 rectoceles (mean extents, 2.85 and 2.45 cm, respectively). Nine cystoceles were revealed by both dynamic MR imaging (mean extent, 4.05 cm) and fluoroscopy (mean extent, 4.55 cm). Seven enteroceles were revealed, one of which was initially not seen on dynamic MR imaging. Two sigmoidoceles were revealed, one of which was not seen on fluoroscopy. The mean extent of the enteroceles and sigmoidoceles on dynamic MR imaging was 3.50 cm, and the mean extent on fluoroscopy was 4.25 cm. Nine of the 10 patients were able to defecate in the supine position on the MR imaging table. Patients were divided equally in their preference for dynamic MR imaging or fluoroscopic cystocolpoproctography. CONCLUSION: Triphasic dynamic MR imaging and triphasic fluoroscopic cystocolpoproctograpy show similar detection rates for prolapse of pelvic organs. Although dynamic MR imaging underestimates the extent of cystoceles and enteroceles, it has the advantage of revealing all pelvic organs and the pelvic floor musculature in a multiplanar cine-loop presentation.     

Assessment of pelvic floor dysfunctions using dynamic magnetic resonance imaging

Purpose

The purpose of this study was to assess pelvic floor dysfunction using dynamic MRI.

Material and methods

A prospective study was carried out on 21 consecutive patients presented during February 2013 to June 2013 with pelvic pain, difficulty in defecation, constipation or organ prolapse. Pelvic floor was imaged using T2-weighted and fast imaging employing steady-state acquisition sequences. Pubococcygeal line was used as the line of reference which further allowed measurement of width and vertical descent of levator hiatus. Anorectal angle was measured to assess relaxation and contraction of puborectalis muscle. Grading of prolapse was classified as mild, moderate and severe. All data were recorded both in resting and during straining phase.

Results

A total of 21 patients were studied, with a mean age of 37.3 (9.4) years with 15 (71.4%) females and 6 (21%) males. Dynamic MR revealed cystocele and rectocele in 7 (33.3%) patients, each. Three (14.28%) patients had enteroceles and spastic pelvic syndrome, each. Only one patient (4.76%) had descending perineal syndrome. Intussusception was observed in 10 (47.6%) patients with commonest type being intra rectal seen in 7 (33.3%) patients.

Conclusion

Dynamic MRI is an ideal, non invasive technique which does not require patient preparation for evaluation of pelvic floor. It acts as one stop shop for diagnosing single or multiple pelvic compartment involvement in patients with pelvic floor dysfunction.