Published online before print March 29, 2002, 10.1148/radiol.2232010665
(Radiology 2002;223:501.)
A more recent version of this article appeared on May 1, 2002
Dynamic MR Imaging of the Pelvic Floor Performed with Patient Sitting in an Open-Magnet Unit versus with Patient Supine in a Closed-Magnet Unit1
Katharina M. Bertschinger, MD,
Frank H. Hetzer, MD,
Justus E. Roos, MD,
Karl Treiber, RT,
Borut Marincek, MD and
Paul R. Hilfiker, MD
1 From the Institute of Diagnostic Radiology (K.M.B., J.E.R., K.T., B.M., P.R.H.) and Department of Visceral and Transplant Surgery (F.H.H.), University Hospital Zurich, Rämistrasse 100, CH-8091 Zurich, Switzerland. Received March 26, 2001; revision requested April 25; revision received August 1; accepted September 17. Address correspondence to P.R.H. (e-mail: paul.hilfiker@mri-roentgen.ch).
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ABSTRACT
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PURPOSE: To compare open-magnet magnetic resonance (MR) imaging performed with the patient sitting with dynamic closed-magnet MR imaging of the pelvic floor performed with the patient supine.
MATERIALS AND METHODS: Thirty-eight patients underwent dynamic 1.5-T closed-magnet pelvic floor MR imaging while in the supine position. Midsagittal T2-weighted single-shot fast spin-echo and T1-weighted multiphase spoiled gradient-recalled-echo (SPGR) MR images were obtained before and after rectal contrast agent administration, respectively, with the patient at rest, straining, and maximally contracting the sphincter. Subsequently, the patient was transferred to an open 0.5-T system. Midsagittal multiphase T1-weighted SPGR MR images were then obtained every 2 seconds with the patient sitting while at rest, maximally contracting the sphincter, straining, and defecating. Images were analyzed with regard to presence of enteroceles, anterior rectoceles, intussusceptions, rectal descents, bladder descents, and vaginal vault descents.
RESULTS: All intussusceptions were missed at supine MR imaging. With sitting MR imaging as the reference standard, the sensitivity of supine MR imaging was 79% for depiction of bladder descents. When MR findings were graded and clinically irrelevant MR findings were excluded, sensitivity increased to 100% for depiction of bladder descents and anterior rectoceles and to 96% for depiction of rectal descents.
CONCLUSION: Dynamic supine MR imaging performed with a closed-configuration unit before and after rectal contrast agent administration appears to be an alternative to sitting MR defecography performed with an open-configuration unit for diagnosis of clinically relevant pelvic floor abnormalities.
© RSNA, 2002
Index terms: Pelvic organs, MR, 757.121411, 757.121412, 757.121416, 757.12143 • Pelvic organs, prolapse, 757.159, 80.1499 • Rectum, abnormalities, 757.159, 757.73
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INTRODUCTION
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Functional disorders of the pelvic floor are a common clinical problem. The diagnosis and treatment of these disorders, which frequently manifest with nonspecific symptoms such as constipation or incontinence, are difficult. Incontinence, descensus, and organ prolapse occur in varying combinations.
The evaluation of defecation with magnetic resonance (MR) imaging has been hampered by the closed architecture of conventional MR systems, which limits patient positioning to the horizontal plane. With the advent of open-configuration MR systems, the acquisition of images with the patient in an upright position during defecation became possible (1,2). However, the availability of vertical open-configuration systems is limited. Dynamic pelvic floor MR imaging with a closed magnet has been used recently to evaluate pelvic floor movement. This examination enables a global view of the pelvic viscera and pelvic floor muscles (3–5). Changes in pelvic floor laxity that are related to urinary incontinence can be seen at MR imaging performed with the patient either supine or sitting, but visibility of these changes is increased at sitting MR imaging (6).
The purpose of this study was to compare open-magnet pelvic floor MR imaging performed with the patient sitting with dynamic closed-magnet pelvic floor MR imaging performed with the patient supine.
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MATERIALS AND METHODS
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Patient Population
For 1 year, March 1999 to February 2000, 38 consecutive patients participated in the study. All patients were women aged 23–78 years (mean age, 56.2 years). In accordance with the guidelines of our institution, written informed consent was obtained from all patients. At the time this study was performed, Swiss law did not require institutional review board approval for this type of study. However, our study was performed in compliance with the Declaration of Helsinki guidelines. All patients had clinical symptoms and were referred for sitting MR defecography by their physicians. All clinical examinations, including those performed to document the patients’ symptoms (Table 1), were conducted by the referring physician. Patients were included in the study only if they were willing to participate and if the time allowed for imaging included the additional time that was necessary to perform closed-magnet MR imaging. Nineteen patients had a clinical history of hysterectomy.
Imaging Technique
MR imaging was performed with 1.5-T closed-configuration (Signa LX; GE Medical Systems, Milwaukee, Wis) and 0.5-T superconducting open-configuration (Signa SP; GE Medical Systems) systems. Before undergoing imaging, the patients were asked to void. Patients first underwent closed-magnet MR imaging while in the supine position. With use of a pelvic phased-array coil, a T2-weighted single-shot fast spin-echo sequence (1,000/20 [repetition time msec/echo time msec], 90° flip angle, 32-mm rectangular field of view, 128 x 256 matrix, 5.0-mm section thickness, 0.5 signal acquired) was performed in the midsagittal plane. During imaging, the patient was asked to relax the pelvic floor muscles, contract the anal sphincter to a maximum, and then relax again. The patient was also asked to increase the intraabdominal pressure by straining and then relaxing. This exercise was repeated four times, and the patient’s performance was directly followed up on the workstation connected to the MR imaging unit.
Afterward, the patient’s rectum was filled with 300 mL of a suspension agent (mashed potatoes) mixed with 1.5 mL of gadopentetate dimeglumine (377 mg/mL) (Magnevist; Schering, Berlin, Germany), which yielded a gadolinium concentration of 2.5 mmol/L (4). Midsagittal MR imaging was then repeated during relaxation, maximal sphincter contraction, and straining with a T1-weighted multiphase spoiled gradient-recalled-echo sequence (14/3, 90° flip angle, 32-mm rectangular field of view, 128 x 256 matrix, 15-mm section thickness, one signal acquired). An image update was provided every 2 seconds. The overall time for supine MR imaging varied between 25 and 35 minutes.
Subsequently, the patient was transferred to the open-configuration MR system, which is in a room next door to the room in which the closed-magnet system is located. The patient was placed upright in the seat of the unit. A flexible transmit-receive radio-frequency coil was strapped around the pelvis. On the basis of transverse localizing image findings, 15-mm-thick multiphase T1-weighted spoiled gradient-recalled-echo images of the region across the rectal canal were obtained in a midsagittal plane. For this sequence, the following parameters were used: 23.9/11.3, 90° flip angle, 32-cm field of view, 256 x 128 matrix, and one signal acquired. Image updates were provided every 2 seconds. After imaging during relaxation, maximal sphincter contraction, and straining, the patient was asked to defecate while imaging was performed. The overall time for sitting MR imaging varied between 9 and 16 minutes.
Image Analysis
Image analysis was based on all sagittal source image and cine loop (before and after enema administration) findings. Prospective image interpretation was performed independently by two radiologists (K.M.B., P.R.H.) who were blinded to the results of the physical examination and surgery performed before MR defecography. The observers were experienced in the assessment of all three compartments of the pelvic floor. In cases in which there was no agreement regarding the classification of the abnormalities initially, a second consensus reading was performed. To reduce recognition bias, the interpretations of images obtained with the closed magnet and of those obtained with the open magnet were performed 2 weeks apart.
Images and cine loops were analyzed with regard to the presence of enteroceles, anterior rectoceles, intussusceptions, rectal descents, bladder descents, and vaginal vault descents. An enterocele was defined as a peritoneal sac that has herniated downward along the ventral rectal wall (7). The size of an anterior rectocele was expressed as the depth of wall protrusion extending beyond the expected margin of the normal rectal wall. Intussusception was defined as rectal wall invagination of varied thickness that descends toward the anal canal. Rectal, bladder, and vaginal vault descents were measured with respect to the inferior pubococcygeal line (Fig 1). Abnormalities were graded as small, moderate, and large (Table 2). The pubococcygeal line was defined as the line joining the inferior border of the symphysis pubis to the last coccygeal joint.
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Figure 1. Rectal contrast agent-enhanced midsagittal T1-weighted 0.5-T open-magnet MR image (23.9/11.3) obtained in a patient sitting at rest. At a separate workstation, descent of the bladder base (white arrow), vaginal vault (black single-headed arrow), and anorectal junction (double-headed arrow) was measured with respect to the inferior pubococcygeal line (line) between the inferior aspect of the symphysis and the last coccygeal joint.
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Sitting MR imaging was considered the reference standard. Therefore, the sensitivity of supine MR imaging for the depiction of abnormalities was calculated as the number of abnormalities depicted at supine MR imaging divided by the number of abnormalities depicted at sitting MR imaging.
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RESULTS
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With both sitting and supine MR imaging methods, evaluation of all three compartments of the pelvic floor was possible. In three cases, disagreement regarding classification of the size of the abnormalities made a second consensus reading necessary: With the 1.5-T MR system, a rectal descent was considered finally as moderate; with the 0.5-T MR system, an enterocele and anterior rectocele were considered finally as moderate. Rectal descents and anterior rectoceles were detected with both methods and were the most common findings (Fig 2). However, at comparison of the sitting and supine MR imaging findings (Table 3), one moderate and three small rectal descents and one moderate and one small enterocele were missed at supine MR imaging (Fig 3). Four small bladder descents and four small anterior rectoceles also were missed at supine MR imaging.
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Figure 2a. Midsagittal MR images obtained in a 72-year-old woman with fecal incontinence and a history of hysterectomy. (a) T2-weighted single-shot fast spin-echo MR image (988/29) obtained before rectal contrast agent administration with the patient supine while straining shows bladder base descent (arrow) of 4.5 cm below the pubococcygeal line (line). (b) T1-weighted multiphase spoiled gradient-recalled-echo MR image (14/3) obtained after rectal contrast agent administration with the patient supine while straining shows that the descent of the bladder base is blocked during straining. Note the excellent delineation of the rectoanal wall, which allows identification of a small anterior rectocele (white arrow) and of the descent of the anorectal junction (black arrow) below the pubococcygeal line (line). (c) T1-weighted multiphase spoiled gradient-recalled-echo MR image (22/11) obtained after rectal contrast agent administration with the patient sitting while straining shows a small anterior rectocele (arrow). The line is the pubococcygeal line. (d) T1-weighted multiphase spoiled gradient-recalled-echo MR image (22/11) obtained after rectal contrast agent administration with the patient sitting while defecating shows moderate descent of the bladder base (white arrow) and anorectal junction (black arrow) below the pubococcygeal line (line).
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Figure 2b. Midsagittal MR images obtained in a 72-year-old woman with fecal incontinence and a history of hysterectomy. (a) T2-weighted single-shot fast spin-echo MR image (988/29) obtained before rectal contrast agent administration with the patient supine while straining shows bladder base descent (arrow) of 4.5 cm below the pubococcygeal line (line). (b) T1-weighted multiphase spoiled gradient-recalled-echo MR image (14/3) obtained after rectal contrast agent administration with the patient supine while straining shows that the descent of the bladder base is blocked during straining. Note the excellent delineation of the rectoanal wall, which allows identification of a small anterior rectocele (white arrow) and of the descent of the anorectal junction (black arrow) below the pubococcygeal line (line). (c) T1-weighted multiphase spoiled gradient-recalled-echo MR image (22/11) obtained after rectal contrast agent administration with the patient sitting while straining shows a small anterior rectocele (arrow). The line is the pubococcygeal line. (d) T1-weighted multiphase spoiled gradient-recalled-echo MR image (22/11) obtained after rectal contrast agent administration with the patient sitting while defecating shows moderate descent of the bladder base (white arrow) and anorectal junction (black arrow) below the pubococcygeal line (line).
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Figure 2c. Midsagittal MR images obtained in a 72-year-old woman with fecal incontinence and a history of hysterectomy. (a) T2-weighted single-shot fast spin-echo MR image (988/29) obtained before rectal contrast agent administration with the patient supine while straining shows bladder base descent (arrow) of 4.5 cm below the pubococcygeal line (line). (b) T1-weighted multiphase spoiled gradient-recalled-echo MR image (14/3) obtained after rectal contrast agent administration with the patient supine while straining shows that the descent of the bladder base is blocked during straining. Note the excellent delineation of the rectoanal wall, which allows identification of a small anterior rectocele (white arrow) and of the descent of the anorectal junction (black arrow) below the pubococcygeal line (line). (c) T1-weighted multiphase spoiled gradient-recalled-echo MR image (22/11) obtained after rectal contrast agent administration with the patient sitting while straining shows a small anterior rectocele (arrow). The line is the pubococcygeal line. (d) T1-weighted multiphase spoiled gradient-recalled-echo MR image (22/11) obtained after rectal contrast agent administration with the patient sitting while defecating shows moderate descent of the bladder base (white arrow) and anorectal junction (black arrow) below the pubococcygeal line (line).
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Figure 2d. Midsagittal MR images obtained in a 72-year-old woman with fecal incontinence and a history of hysterectomy. (a) T2-weighted single-shot fast spin-echo MR image (988/29) obtained before rectal contrast agent administration with the patient supine while straining shows bladder base descent (arrow) of 4.5 cm below the pubococcygeal line (line). (b) T1-weighted multiphase spoiled gradient-recalled-echo MR image (14/3) obtained after rectal contrast agent administration with the patient supine while straining shows that the descent of the bladder base is blocked during straining. Note the excellent delineation of the rectoanal wall, which allows identification of a small anterior rectocele (white arrow) and of the descent of the anorectal junction (black arrow) below the pubococcygeal line (line). (c) T1-weighted multiphase spoiled gradient-recalled-echo MR image (22/11) obtained after rectal contrast agent administration with the patient sitting while straining shows a small anterior rectocele (arrow). The line is the pubococcygeal line. (d) T1-weighted multiphase spoiled gradient-recalled-echo MR image (22/11) obtained after rectal contrast agent administration with the patient sitting while defecating shows moderate descent of the bladder base (white arrow) and anorectal junction (black arrow) below the pubococcygeal line (line).
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Figure 3a. Midsagittal MR images obtained after hysterectomy in a 45-year-old four-parous woman who had a feeling of a foreign body during defecation. At clinical examination, an anterior rectocele was suspected. (a) On the T2-weighted single-shot fast spin-echo MR image (935/29) obtained before rectal contrast agent administration with the patient supine while straining, an enterocele is not evident. (b) T1-weighted multiphase spoiled gradient-recalled-echo MR image (14.0/2.9) obtained after rectal contrast agent administration with the patient supine while straining shows only a partly stool-filled small anterior rectocele (arrow). (c) T1-weighted multiphase spoiled gradient-recalled-echo MR image (22.5/10.8) obtained after rectal contrast agent administration with the patient sitting while straining shows an anterior rectocele (white arrow) and a moderate hernia of the sigmoid colon (black arrow).
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Figure 3b. Midsagittal MR images obtained after hysterectomy in a 45-year-old four-parous woman who had a feeling of a foreign body during defecation. At clinical examination, an anterior rectocele was suspected. (a) On the T2-weighted single-shot fast spin-echo MR image (935/29) obtained before rectal contrast agent administration with the patient supine while straining, an enterocele is not evident. (b) T1-weighted multiphase spoiled gradient-recalled-echo MR image (14.0/2.9) obtained after rectal contrast agent administration with the patient supine while straining shows only a partly stool-filled small anterior rectocele (arrow). (c) T1-weighted multiphase spoiled gradient-recalled-echo MR image (22.5/10.8) obtained after rectal contrast agent administration with the patient sitting while straining shows an anterior rectocele (white arrow) and a moderate hernia of the sigmoid colon (black arrow).
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Figure 3c. Midsagittal MR images obtained after hysterectomy in a 45-year-old four-parous woman who had a feeling of a foreign body during defecation. At clinical examination, an anterior rectocele was suspected. (a) On the T2-weighted single-shot fast spin-echo MR image (935/29) obtained before rectal contrast agent administration with the patient supine while straining, an enterocele is not evident. (b) T1-weighted multiphase spoiled gradient-recalled-echo MR image (14.0/2.9) obtained after rectal contrast agent administration with the patient supine while straining shows only a partly stool-filled small anterior rectocele (arrow). (c) T1-weighted multiphase spoiled gradient-recalled-echo MR image (22.5/10.8) obtained after rectal contrast agent administration with the patient sitting while straining shows an anterior rectocele (white arrow) and a moderate hernia of the sigmoid colon (black arrow).
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No abnormalities that were seen at supine MR imaging were missed at sitting MR imaging. However, all of the patients with small findings of rectal descent, bladder descent, vaginal vault descent, and anterior rectoceles but without additional moderate or large findings at sitting MR imaging had no clinical findings at physical examination. All intussusceptions were depicted only at sitting MR defecography (Fig 4); these abnormalities were missed at supine MR imaging.
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Figure 4a. Midsagittal MR images obtained in a 40-year-old two-parous woman with symptoms of incomplete evacuation. Clinical examination revealed an anterior rectocele. (a) On the T2-weighted single-shot fast spin-echo MR image (1,075.0/30.5) obtained before rectal contrast agent administration with the patient supine while straining, an enterocele is not evident. (b) On the T1-weighted multiphase spoiled gradient-recalled-echo MR image (8.7/2.0) obtained after rectal contrast agent administration with the patient supine while straining, an enterocele is excluded and a moderately sized anterior rectocele (arrow) is seen. (c, d) T1-weighted multiphase spoiled gradient-recalled-echo MR images (22.1/10.6) obtained after rectal contrast agent administration. (c) During straining, a moderately sized anterior rectocele (arrow) is seen. (d) During defecation, an intussusception (white arrows) that caused incomplete evacuation is seen. The moderately sized anterior rectocele (black arrow) also is seen.
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Figure 4b. Midsagittal MR images obtained in a 40-year-old two-parous woman with symptoms of incomplete evacuation. Clinical examination revealed an anterior rectocele. (a) On the T2-weighted single-shot fast spin-echo MR image (1,075.0/30.5) obtained before rectal contrast agent administration with the patient supine while straining, an enterocele is not evident. (b) On the T1-weighted multiphase spoiled gradient-recalled-echo MR image (8.7/2.0) obtained after rectal contrast agent administration with the patient supine while straining, an enterocele is excluded and a moderately sized anterior rectocele (arrow) is seen. (c, d) T1-weighted multiphase spoiled gradient-recalled-echo MR images (22.1/10.6) obtained after rectal contrast agent administration. (c) During straining, a moderately sized anterior rectocele (arrow) is seen. (d) During defecation, an intussusception (white arrows) that caused incomplete evacuation is seen. The moderately sized anterior rectocele (black arrow) also is seen.
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Figure 4c. Midsagittal MR images obtained in a 40-year-old two-parous woman with symptoms of incomplete evacuation. Clinical examination revealed an anterior rectocele. (a) On the T2-weighted single-shot fast spin-echo MR image (1,075.0/30.5) obtained before rectal contrast agent administration with the patient supine while straining, an enterocele is not evident. (b) On the T1-weighted multiphase spoiled gradient-recalled-echo MR image (8.7/2.0) obtained after rectal contrast agent administration with the patient supine while straining, an enterocele is excluded and a moderately sized anterior rectocele (arrow) is seen. (c, d) T1-weighted multiphase spoiled gradient-recalled-echo MR images (22.1/10.6) obtained after rectal contrast agent administration. (c) During straining, a moderately sized anterior rectocele (arrow) is seen. (d) During defecation, an intussusception (white arrows) that caused incomplete evacuation is seen. The moderately sized anterior rectocele (black arrow) also is seen.
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Figure 4d. Midsagittal MR images obtained in a 40-year-old two-parous woman with symptoms of incomplete evacuation. Clinical examination revealed an anterior rectocele. (a) On the T2-weighted single-shot fast spin-echo MR image (1,075.0/30.5) obtained before rectal contrast agent administration with the patient supine while straining, an enterocele is not evident. (b) On the T1-weighted multiphase spoiled gradient-recalled-echo MR image (8.7/2.0) obtained after rectal contrast agent administration with the patient supine while straining, an enterocele is excluded and a moderately sized anterior rectocele (arrow) is seen. (c, d) T1-weighted multiphase spoiled gradient-recalled-echo MR images (22.1/10.6) obtained after rectal contrast agent administration. (c) During straining, a moderately sized anterior rectocele (arrow) is seen. (d) During defecation, an intussusception (white arrows) that caused incomplete evacuation is seen. The moderately sized anterior rectocele (black arrow) also is seen.
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With sitting MR imaging as the reference standard, the sensitivity of supine MR imaging for the depiction of abnormalities was poor to moderate, 0%–89%, with the exception of 100% sensitivity for the depiction of vaginal vault descents (Table 4). When small anterior rectoceles, small bladder descents, small vaginal vault descents, and small rectal descents were excluded from analysis, the sensitivity of supine MR imaging increased to 100% for the depiction of bladder descents and anterior rectoceles and to 96% for the depiction of rectal descents (Table 5).
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TABLE 4. Overall Sensitivity of Supine MR Imaging for Detection of Pelvic Floor Abnormalities, with Sitting MR Imaging as Reference Standard
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TABLE 5. Sensitivity of Supine MR Imaging for Detection of Clinically Important Abnormalities, with Sitting MR Imaging as Reference Standard
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DISCUSSION
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A thorough evaluation of the pelvic floor is crucial for any patient who presents with stress incontinence and/or symptoms of pelvic prolapse. Both patients in the postmenopausal stage and patients after hysterectomy (as in our study group) in particular report having pelvic floor discomfort. Physical examination is often insufficient for defining the nature and degree of visceral prolapse. Because there are often multiple defects in the female pelvis, attention to an anterior prolapse without attention to the pelvic floor may predispose the patient to increased risk of postoperative enterocele, uterine prolapse, and/or rectocele.
A variety of radiologic techniques have been developed for the accurate visualization and quantitative assessment of pelvic floor structures. MR defecography with an open-configuration magnet enables accurate assessment of the anorectal morphologic structures and of function in relation to the surrounding structures without exposure of the patient to harmful ionizing radiation (1). Sagittal multiphase gradient-echo MR imaging enables complete assessment of the anal canal, the position of the anorectal junction, the vaginal vault, the bladder base, and the function of the puborectal muscle (2). In this study, with both closed- and open-magnet MR imaging methods, the spatial resolution was adequate for demonstration of the relevant morphologic structures, and the temporal resolution was sufficient for assessment of pelvic floor dynamics.
In this study, although most of the abnormalities could be identified at both sitting and supine MR imaging, they were best demonstrated with the sitting MR examination. This observation correlates with the fact that women with stress incontinence rarely report having leakage while in the supine position (4). Overall, MR imaging performed with the patient sitting depicted a greater degree of pelvic floor laxity (ie, organ descent) and more anterior rectoceles and enteroceles; otherwise, it was not superior to MR imaging performed with the patient supine for depicting clinically relevant findings.
Clinical examination is usually sufficient for the diagnosis of most pelvic floor disorders (8). However, patients may present with symptoms that involve only one compartment of the pelvic floor but undergo dynamic radiography of the bladder and rectum that depicts a multicompartment abnormality (9). Therefore, one or more coexisting types of prolapse may be missed or underdiagnosed at clinical examination; for example, an enterocele may be concealed by a large rectocele (10,11). Quantitative measurements are difficult to obtain at clinical examination only, but they are helpful when surgical treatment or follow-up after surgery is mandatory.
Different MR imaging techniques for accurate assessment and quantitative measurement of all relevant pelvic floor structures are described in the literature. Kruyt et al (3) and Yang et al (4) evaluated supine MR imaging for the depiction of normal and abnormal changes in the anus, rectum, and female pelvic organs of patients with genital prolapse. Goodrich et al (12) confirmed the clinical relevance of dynamic closed-magnet MR imaging findings in preoperative diagnosis and postoperative follow-up. No opacification of the pelvic organs was used in these studies. Other MR studies (13) have been performed by means of opacification of the urethra, bladder, vagina, and rectum with saline solution, gadopentetate dimeglumine, and ultrasonographic gel.
In our study, all three pelvic floor compartments could be identified after rectal contrast agent administration, without the need for further opacification of the vagina or bladder, owing to the excellent soft-tissue contrast that is inherent of MR imaging. In the present study, the numbers of continent patients who had small descents of the bladder base that were detected with MR imaging without clinical symptoms of urinary incontinence or clinical findings correlate well with the work of Yang et al (4), who reported that in continent women, the bladder base may descend up to 1 cm below the pubococcygeal line during maximal straining. One explanation for the high numbers of small anterior rectoceles, small rectal descents, and small vaginal vault descents in this study is possible damage to the pelvic floor. In addition, rectoceles smaller than 2 cm are described as findings in asymptomatic individuals (14,15).
Sitting MR imaging depicted a higher degree of pelvic floor laxity, which manifested as increased descent of the bladder base and anorectal junction and an increased prevalence of small anterior rectoceles. However, the removal of the subgroup of small findings from statistical calculations resulted in a higher sensitivity for closed-magnet MR imaging, which correlates well with clinical symptoms.
The grading of small, moderate, and large findings is a straightforward and reproducible method of describing, staging, and quantifying pelvic visceral prolapse. The two MR imaging techniques described herein had concordant findings with regard to the presence and the severity grade of organ prolapse in the majority of patients. In most previously published reports (13,16–18) that involved a comparison of dynamic supine MR imaging with sitting MR imaging, no grading systems were used. In one study, Kelvin et al (19) graded the findings in all three pelvic floor compartments at supine MR imaging and sitting radiography of the bladder and rectum. The results of that study are comparable to our findings. At both MR imaging examinations, the degree of prolapse was graded similarly, although dynamic supine MR imaging resulted in underestimations of the extent of cystoceles, enteroceles, and vaginal vault prolapse. Other authors (20) have applied another type of grading system, but no reference standard, such as sitting MR defecography or conventional radiography of the bladder and rectum, was used.
This study had limitations. Our conclusions are limited because of the small sample size and because we did not match the MR imaging findings to those in a control group. Also, our study protocol did not include MR imaging during defecation in the supine position, which was not possible owing to our institutional guidelines. Nevertheless, our study results demonstrate that dynamic supine MR imaging of the pelvic floor after rectal contrast agent administration may be an alternative to sitting MR defecography for the depiction of relevant findings.
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FOOTNOTES
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Author contributions: Guarantors of integrity of entire study, K.M.B., P.R.H.; study concepts and design, K.M.B., P.R.H.; literature research, K.M.B.; clinical studies, K.M.B., F.H.H.; data acquisition, J.E.R., K.M.B., K.T.; data analysis/interpretation, J.E.R., K.M.B., P.R.H.; statistical analysis, K.M.B., P.R.H.; manuscript preparation, J.E.R., K.M.B., P.R.H.; manuscript definition of intellectual content and editing, K.M.B., P.R.H., B.M.; manuscript revision/review, J.E.R., P.R.H., F.H.H.; manuscript final version approval, all authors.
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REFERENCES
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|---|
- Schoenenberger AW, Debatin JF, Guldenschuh I, Hany TF, Steiner P, Krestin GP. Dynamic MR defecography with a superconducting, open-configuration MR system. Radiology 1998; 206:641-646.
- Hillier PR, Debatin JF, Schwizer W, Schoenenberger AW, Fried M, Marincek B. MR defecography: depiction of anorectal anatomy and pathology. J Comput Assist Tomogr 1998; 22:749-755.
- Kruyt RH, Delemarre JBVM, Doornbos J, Vogel HJ. Normal anorectum: dynamic MR imaging anatomy. Radiology 1991; 179:159-163.
- Yang A, Mostwin JL, Rosenheim NB, Zerhouni EA. Pelvic floor descent in women: dynamic evaluation with fast MR imaging and cinematic display. Radiology 1991; 179:25-33.
- Goodrich MA, Webb MJ, King BF, Bampton AEH, Campeau NG, Riedener SJ. Magnetic resonance imaging of pelvic floor relaxation: dynamic analysis and evaluation of patients before and after surgical repair. Obstet Gynecol 1993; 82:883-891.
- Fielding JR, Griffiths DJ, Versi E, Mulkern RV, Tee MLT, Jolesz FA. MR imaging of pelvic floor continence mechanisms in the supine and sitting positions. AJR Am J Roentgenol 1998; 171:1607-1610.
- Kelvin FM, Maglinte DDT, Hornback JA, Benson JT. Pelvic prolapse: assessment with evacuation proctography (defecography). Radiology 1992; 184:547-551.
- Siproudhis L, Ropert A, Vilotte J, et al. How accurate is clinical examination in diagnosing and quantifying perirectal disorders? A prospective study in a group of 50 patients complaining of defecatory difficulties. Dis Colon Rectum 1993; 36:430-438.
- Maglinte DDT, Kelvin FM, Fitzgerald K, Hale DS, Benson JT. Association of compartment defects in pelvic floor dysfunction. AJR Am J Roentgenol 1999; 172:439-444.
- Shull BL. Clinical evaluation of woman with pelvic support defects. Clin Obstet Gynecol 1993; 36:939-951.
- Mellgren A, Johansson C, Dolk A, et al. Enterocele demonstrated by defaecography is associated with other pelvic floor disorders. Int J Colorectal Dis 1994; 9:121-124.
- Goodrich MA, Webb MJ, King BF, Bampton AE, Campeau NG, Riederer SJ. Magnetic resonance imaging of pelvic floor relaxation: dynamic analysis and evaluation of patients before and after surgical repair. Obstet Gynecol 1993; 82:883-991.
- Lienemann A, Anthuber C, Baron A, Kohz P, Reiser M. Dynamic MR colpocystography assessing pelvic-floor descent. Eur Radiol 1997; 7:1309-1317.
- Shorvon PJ, McHugh S, Sommers S, Stevenson GW. Video defecography in normal volunteers: results and implications. Gut 1989; 30:1737-1749.
- Peifer J, Oliviera L, Park UC, Agachan FW, Wexner SD. Are interpretations of video defecographies reliable and reproducible?. Int J Colorect Dis 1997; 12:67-72.
- Healy JC, Halligan S, Reznek RH, et al. Dynamic MR imaging compared with evacuation proctography when evaluation anorectal configuration and pelvic floor movement. AJR Am J Roentgenol 1997; 169:775-779.
- Vanbeckevoort D, Van Hoe L, Oyen R, Ponette E, Deprest J. Pelvic floor descent in females: comparative study of colpocystodefecography and dynamic fast MR imaging. J Magn Reson Imaging 1999; 9:373-377.
- Gufler H, Laubenberger J, De Gregorio G, Dohnicht S, Langer M. Pelvic floor descent: dynamic MR imaging using a half-Fourier RARE sequence. J Magn Reson Imaging 1999; 9:378-383.
- Kelvin FM, Maglinte DDT, Hale DS, Benson JT. Female pelvic organ prolapse: a comparison of triphasic dynamic MR imaging and triphasic fluoroscopic cystocolpoproctography. AJR Am J Roentgenol 2000; 174:81-88.
- Comiter CV, Vasavada SP, Barbaric ZL, Gousse AE, Raz S. Grading pelvic prolapse and pelvic floor relaxation using dynamic MRI. Urology 1999; 3:454-457.
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ABSTRACT
INTRODUCTION
