Hiatal Dimensions Research Articles

Can the Paula method facilitate co-contraction of the pelvic floor muscles? A 4D ultrasound study

The aim was to compare constriction of the levator hiatus (LH) and reduction of pelvic floor muscle (PFM) length during instruction of the Paula method (contraction of ring musculature of the mouth) and contraction of the PFM. Seventeen pregnant or postpartum women, mean age 28.6 (range 20-35) participated. A Voluson E8 ultrasound machine with 4-8 MHz curved array 3D/4D transducer (RAB 4-7l/obstetric) was used. Measurements were performed in the axial plane of minimal hiatal dimensions. Muscle length was calculated as circumference of the LH minus the suprapubic arch. Differences between groups were analyzed using Wilcoxon signed rank test. Significance level was set to 0.05. There was a significant reduction of the LH area (p<0.001) and muscle length (p<0.001) during PFM contraction, but not during contraction according to the Paula method, p=0.51 and p=0.31, respectively. The Paula method did not facilitate PFM contraction.

Measuring the levator hiatus with axial MRI sequences: Adjusting the angle of acquisition

We aimed to compare MRI measurements of the female levator hiatus and the most caudal "levator ani" muscles between image slices in a plane axial to the body (AxB) and an axial plane parallel to the direction of the puborectalis muscle (AxPRM). We performed high-resolution, T2-weighted axial magnetic resonance imaging (in two different planes) on 20 sequentially recruited asymptomatic nulliparous women. Levator hiatus measurements were compared between the two planes. The mean tilt angle of the AxPRM slices relative to the AxB slices was 18.9° (SD 8.5) and the area of the levator hiatus was 10% greater (P=0.04) in the AxPRM plane. By rotating the acquisition plane to be parallel to the puborectalis muscle (sometimes called the plane of minimal hiatal dimensions), some of the measurements of the distal and medial pelvic floor muscles (and the hiatus defined by them) are altered. This issue is important because both MRI and 3D ultrasound are increasingly being used to evaluate the pelvic floor hiatus, and its relationship to childbirth injury and pelvic floor disorders. To make meaningful comparisons, it is important that both modalities are measuring the same thing.

Does levator ani injury affect cystocele type?

To determine the prevalence of levator ani injury in patients with different types of cystocele, as defined by translabial ultrasound, in order to shed light on potential pathophysiological mechanisms. The datasets of 222 women who had undergone a physical examination, urodynamic testing and four-dimensional (4D) pelvic floor ultrasound were evaluated offline for prolapse, levator ani hiatal dimensions and levator ani trauma using tomographic ultrasound imaging (TUI), blinded against all clinical and urodynamic data. Cystoceles reaching below the symphysis pubis on ultrasound examination were classified based on bladder neck position, retrovesical angle (RVA) and urethral rotation as Green II (cystourethrocele) or Green III (cystocele with intact RVA). Of 102 women who had a cystocele reaching below the symphysis pubis, 63 were classified as a Green type II cystocele and 39 as a Green type III cystocele. Women with Green type III cystoceles were older (59.4 vs. 48.7 years, P < 0.001), and had more severe prolapse (71 vs. 43%, P = 0.004) and objective voiding dysfunction (39 vs. 18%, P = 0.018). Women with Green III cystoceles also had larger hiatal dimensions and were more often diagnosed with an avulsion of the levator ani muscle (69 vs. 35%, P = 0.001). A cystocele with an intact RVA is more likely to be associated with avulsion injury of the levator ani muscle and thus more likely to be caused by birth-related trauma. This contradicts the commonly held belief that such cystoceles are caused by central rather than by lateral fascial defects.

P26.06: Changes in genital hiatus after sacrocolpopexy

To demonstrate the anatomical changes of genital hiatus measured by transperineal ultrasound (US), in patients undergoing laparoscopic sacrocolpopexy (SCP). Retrospective study performed at the Pelvic Floor Unit of the University Hospitals Leuven, Belgium. Clinical and operative data were retrieved from the medical records. Eligible were patients who underwent surgery for level I defects, presenting as clinical POPQ ≥ stage II, undergoing SCP with both pre- and post-operative US examination available. Volumes were obtained at rest and on maximal Valsalva. Genital hiatus was measured as antero-posterior (AP) and right-left (RL) diameter as well as area of hiatus. 25 patients were eligible for the study, mean (range) age 58 (29–83) years. Indications for surgery were symptomatic vault (16/25) or uterine (9/25) prolapse. 15/25 were with previous anterior repair. 16 (64%) patients underwent SCP, 5 (20%) cervicopexy and 4 (16%) hysteropexy. Ultrapro mesh was used in 14 (56%) patients, Gynemesh in 9 (36%) and in two more cases SIS and Pelvicol were implanted. There was significant difference between pre- and post surgical level I measurements (P < 0.0001). Comparisons of pre- and post-operative data were showing no difference in US measures of genital hiatus both if they were taken in rest or at maximal valsalva (table). Moreover no difference was seen regarding the type of operation or type of material used. We did not observe any significant difference in any of the genital hiatal dimensions measured by transperineal ultrasound. Even if the posterior mesh used for this operation is attached at the levator muscle at level III, no narrowing was observed. P26.06: Table 1. US hiatal measures pre- and post-surgery; results shown as mean (SD)

Interobserver and interdisciplinary reproducibility of 3D endovaginal ultrasound assessment of pelvic floor anatomy

the study aims were to evaluate (1) the interobserver and (2) the interdisciplinary repeatability of levator hiatus, urethral thickness, and anorectal angle measurements using three-dimensional endovaginal ultrasound (3D-EVUS). twenty-seven nulliparous asymptomatic females were imaged with 3D-EVUS. Analyses were conducted off-line from stored 3D volumes by six readers (two radiologists, two urogynecologists, and two colorectal surgeons) using a standardized technique. Reproducibility was determined using the interclass correlation coefficients (ICC). the overall interobserver repeatability for levator hiatus dimensions was good to excellent (ICC, 0.655-0.889), for urethral thickness was good (ICC, 0.624), and for anorectal angle was moderate (ICC, 0472). The interdisciplinary repeatability for levator hiatus indices was good to excellent (ICC, 0.639-0.915), for urethral thickness was moderate to good (ICC, 0.565-0.671), and for anorectal angle was fair to moderate (ICC, 0.204-0.434). 3D-EVUS yields reproducible measurements of levator hiatus dimensions and urethral thickness in asymptomatic nulliparous women.

Three‐dimensional ultrasound of the pelvic floor 2 days after first delivery: influence of constitutional and obstetric factors

Morphological changes of the pelvic floor during pregnancy and delivery can be visualized by three-dimensional (3D) perineal ultrasound. The aim of this study was to compare biometric measurements of the levator ani muscle according to maternal constitutional factors, delivery mode and size of the baby immediately after the first delivery. In this prospective observational study, 130 primiparae were recruited (all of them Caucasians with singleton pregnancy and cephalic presentation). A 3D perineal ultrasound scan was performed on the second day after delivery with standardized settings. Volumes were obtained at rest and on Valsalva maneuver, and biometric measurements of the levator hiatus were determined in the axial plane. Different obstetric and constitutional parameters were obtained from our clinical files. All biometric measurements of the levator hiatus were significantly greater in the vaginal delivery group than in the Cesarean section group (P < 0.001), whereas subgroup analysis within the vaginal (spontaneous vs. operative vaginal) and Cesarean (primary vs. secondary) delivery groups did not show statistically significant differences. There was no demonstrable influence of maternal constitutional factors (age, body mass index (BMI)) or different obstetric parameters (length of second stage of labor, episiotomy, maternal injuries) on levator hiatus size postpartum, even in subgroups that delivered vaginally. Women with de novo postpartum stress incontinence showed a significantly higher mean levator hiatus transverse diameter and larger hiatal area on Valsalva maneuver (P < 0.05). There was also a positive but very weak correlation between the newborn's head circumference and hiatal dimensions at Valsalva maneuver (P < 0.05). Pelvic floor imaging by 3D ultrasound is easily accessible even on the first days after delivery and can provide useful information on morphological changes of the levator ani muscle. In our study, women with vaginal or operative vaginal delivery had a significantly larger hiatal area and transverse diameter than women who delivered by Cesarean section. Maternal constitutional factors (BMI, age) and duration of second stage of labor had no influence on the biometric measurements of hiatal area, whereas weight and head circumference of the baby showed a positive correlation with area of the levator hiatus.

Can levator avulsion be predicted antenatally?

We sought to determine whether antepartum prediction of major levator trauma is feasible. A prospective longitudinal study was undertaken on 488 pregnant nulliparous women seen between 36-38 weeks and again 4 months after delivery. All underwent an interview and 4-dimensional transperineal ultrasound. Diagnosis of levator trauma (avulsion) on tomographic ultrasound was correlated with predelivery demographic variables and ultrasound parameters. In all, 367 women returned for postpartum assessment after normal vaginal delivery (n = 187), vacuum/forceps (n = 54), and cesarean section (n = 126). Avulsion was diagnosed in 34 vaginally parous women (14%). Maternal age, family history of cesarean section, hiatal dimensions, levator muscle strain, bladder neck descent, and subpubic arch angle were not associated with avulsion. The only predictor identified was a lower body mass index (P = .005). Antepartum prediction of major levator trauma may be difficult or impossible. Future studies should focus on modification of current obstetric practices and antepartum interventions applicable to the general population.

How much does the levator hiatus have to stretch during childbirth?

This study was designed to define the degree of stretch/strain required of the levator hiatus in childbirth. There have been attempts at defining the distension required for vaginal childbirth with the help of individual data sets, but from previous work it is clear that hiatal dimensions and distensibility are likely to vary greatly between individuals. Retrospective observational study. Nepean Hospital, University of Sydney. Nulliparous women at 36-38 week's gestation. The ultrasound data sets of 227 nulliparous women examined at 36-38 week's gestation were investigated using post-processing software. Minimal hiatal diameters, subpubic arch, circumference and area were measured at rest, on Valsalva and pelvic floor muscle contraction. To estimate required hiatal distension at vaginal birth we used neonatal biometric data obtained in a Caucasian population. The muscle 'strain' or 'stretch ratio' required to allow delivery of a Caucasian baby of average size was calculated from dimensions at rest and on maximal Valsalva. Degree of stretch/strain required of the levator hiatus in childbirth. Results The mean strain (stretch ratio) required for vaginal delivery was calculated as 1.47 (range 0.62-2.76; SD 0.39) from resting length, and 1.07 (range 0.25-2.45; SD 0.44) when calculated from dimensions at maximal Valsalva. This implies that, from dimensions at maximal Valsalva, some women will have to distend only 25%, others by 245%. We have obtained normative data for the required distension of the levator hiatus in a largely Caucasian population.

OC05.04: Avulsion defect and cystocele - is there a link?

We aimed to determine the prevalence of levator trauma in patients with cystocele, in an attempt to shed light on potential pathophysiological mechanisms. We reviewed the datasets of 222 women, who had undergone physical examination, urodynamics, and 4D pelvic floor US (GE Kretz Voluson 730 expert), for prolapse, levator biometry and avulsion, using tomographic ultrasound imaging (TUI). Cystoceles reaching below the symphysis pubis were classified based on bladder neck position, retrovesical angle (RVA) and urethral rotation as Green II i.e. cystourethrocele (RVA ≥ 140°), or Green III (RVA < 140°). US analysis was performed offline (GE Kretz 4DView 5.0) blinded against all clinical and urodynamic data. Mean age was 55 years, median parity 3. Patients presented with stress incontinence (SI, 78%), urge incontinence (UI, 72%), frequency (31%), nocturia (48%), voiding dysfunction (VD, 24%), and prolapse (70%). Urodynamic testing showed SI (67%), UI (25%), VD (30%), and sensory urgency (16%). 39 datasets were excluded from analysis due to previous surgery. 103 women had a cystocele below the symphysis pubis and were classified as Green II (62) or Green III (41). Women with Green III cystocele were older, had more severe prolapse, but less SI. They were more likely to have objective VD, larger bladder capacity and larger residual volumes. Women with Green III cystoceles were more likely to suffer from levator avulsion defects and showed a higher number of abnormal slices on TUI. Hiatal dimensions were higher in Green III, especially on pelvic floor muscle contraction. A cystocele with intact RVA is more likely to be associated with avulsion defects of the levator ani and thus more likely to be caused by birth related trauma. This contradicts the commonly held belief that such cystoceles are due to central rather than lateral defects.

The Effect of Childbirth on Hiatal Dimensions

To estimate changes in levator hiatal dimensions after childbirth in women with and without ultrasonographically visible morphological abnormalities of the levator ani and to correlate those changes with delivery mode. A total of 296 nulliparous women were recruited. They were examined with four-dimensional translabial ultrasonography at 36-38 weeks of gestation and at 3-4 months postpartum. Peripartal changes in levator hiatal dimensions were correlated with delivery data. Mean postpartum follow-up was 5.3 months (median 4.1, interquartile range 3.7 to 5.1). Of 212 women who returned for follow-up, 101 had had normal vaginal deliveries (48%), 31 vacuum/forceps (15%), and 80 cesarean deliveries (38%). After cesarean delivery, there was a decrease in the mean hiatal area on Valsalva maneuver of 8.5% (P=.005). Vaginal delivery without avulsion was associated with an increase of 6% (P=.035). In women with avulsion injury, hiatal area increased by 28% (P=.002). Mean postpartum hiatal area on Valsalva was 25.46 cm after vaginal delivery with avulsion, 22.61 cm without avulsion, and 19.13 cm in the cesarean delivery group. After avulsion, hiatal area on contraction also increased significantly (P<.001). Vaginal childbirth results in enlargement of the levator hiatus, especially after an avulsion. However, even without macroscopic levator trauma, there may be increased distensibility of the hiatus, which may be another mechanism leading to enlargement of the hiatus and pelvic organ prolapse. II.

Tomographic ultrasound imaging of the pelvic floor: which levels matter most?

Tomographic ultrasound imaging has greatly simplified pelvic floor assessment. Abnormalities of the insertion of the levator ani can be documented in a single frame. In this study we aimed to determine which levels of the levator hiatus are associated with alterations in ultrasound parameters of pelvic organ support. This was a subanalysis of a study conducted in 296 women seen before and after their first delivery. We analyzed postpartum changes in bladder neck descent and hiatal area as indicators of altered pelvic organ support. Tomographic ultrasound examination was performed on volumes obtained at maximal pelvic floor muscle contraction, at 2.5-mm slice intervals, from 5 mm below to 12.5 mm above the plane of minimal hiatal dimensions. Two hundred and eight recruits (70%) returned for a postnatal appointment. Of these, 130 had delivered vaginally and 26 (20%) were diagnosed with an avulsion injury. An abnormality in slices 3-8 was associated with increased bladder neck descent postpartum (P = 0.038 to P = 0.001) and increased hiatal area on Valsalva maneuver (P = 0.029 to P < 0.001). This was not the case for the two most distal slices. We found no association between levator ani defects observed on tomographic ultrasound imaging below the plane of minimal hiatal dimensions and indices of increased hiatal distension or bladder neck descent on Valsalva maneuver. This implies that defects observed below this plane are either irrelevant for pelvic organ support or artifactual.

The effect of levator avulsion on hiatal dimension and function

Pelvic floor trauma as a result of vaginal childbirth can cause significant pelvic floor morbidity. In this observational study, we intended to define whether such trauma is associated with abnormal hiatal biometry and/or abnormal biomechanical properties of the levator muscle. The datasets of 414 urogynecologic patients were assessed in a retrospective study. Patients underwent an interview, clinical examination, and 3-/4-dimensional pelvic floor ultrasound. All analysis was performed offline using proprietary software. Hiatal dimensions and strain were measured. In 21.1% of parous women with a history of vaginal delivery, an avulsion of the levator muscle was diagnosed, and in 8.6% it was bilateral. The relative risk of abnormal distensibility was 3.5 (95% confidence interval, 1.7-6.5) in unilateral and 3.96 (95% confidence interval, 1.7-9.2) in bilateral avulsion. Avulsion increased muscle distensibility on Valsalva and reduced muscle shortening on pelvic floor muscle contraction. Avulsion injury is associated with abnormal levator biometry and function.

Interobserver repeatability of three‐ and four‐dimensional transperineal ultrasound assessment of pelvic floor muscle anatomy and function

To evaluate the interobserver repeatability of measurement of the pubovisceral muscle and levator hiatus, and the position of related organs, during rest, muscle contraction and Valsalva maneuver using three- and four-dimensional (3D and 4D) transperineal ultrasound. Seventeen women were included in the study. The position and dimensions of the pubovisceral muscle and levator hiatus in patients at rest and during contraction and Valsalva were determined from stored 3D and 4D ultrasound volumes. Analyses were conducted offline by two observers blinded to the clinical data and to each others' measurements. Measurements of levator hiatal dimensions at rest demonstrated intraclass correlation coefficient (ICC) values of 0.92 to 0.96. The ICC values for pubovisceral muscle thickness at rest varied between good and very good (ICC, 0.61-0.93), regardless of plane. During contraction, the ICC values for all measured parameters were very good, varying between 0.61 and 0.92. Measurement of the transverse diameter of the levator hiatus during the Valsalva maneuver showed good reliability (ICC, 0.86), but assessment of the anterior and posterior borders of the levator hiatus was only possible in 29% of cases. 3D and 4D transperineal ultrasound measurement of the pubovisceral muscle and levator hiatus is reliable in women with no or minor symptoms of prolapse at rest and during contraction. The technique for recording during the Valsalva maneuver requires improvement if it is to be useful in the diagnosis of pelvic organ prolapse.

18th World Congress on Ultrasound in Obstetrics and Gynecology, 24–28 August 2008, Chicago, USA: presentations and awards

When asked to introduce Larry Platt as the 2008 Gold Medal recipient, I was more than delighted to do so. One might consider this to be a daunting task. However, since Larry’s career is so robust, it was actually easy to chronicle his contributions through the years. To me, the Ian Donald Gold Medal Award is the greatest honor that one can receive in our field of obstetric and gynecological ultrasonography. Since it carries so much respect, when I heard that Larry Platt was this year’s recipient I thought to myself, ‘it’s about time’. Why? Firstly, Larry has been a prolific contributor to the literature. Secondly, he has been a tenacious supporter of ultrasound education. And thirdly, aside from Stuart Campbell, I can think of no one who has been a greater advocate for ISUOG. He has served as President of the Society, Associate Editor of Ultrasound in Obstetrics and Gynecology, and has been on the Board for many years; he has simply put ISUOG first, ahead of his many other responsibilities. When I recently thumbed through my most recent book on ultrasound, I found that I had cited Larry’s work in five different chapters. First and foremost, one cannot mention his name without connecting it to the wonderful contribution that he and Frank Manning made in designing the biophysical profile. It is hard to believe that this was published 28 years ago, and is still being used in its original form by virtually everyone managing

Constriction of the levator hiatus during instruction of pelvic floor or transversus abdominis contraction: a 4D ultrasound study

A new theory claims that the pelvic floor muscles (PFM) can be trained via the transversus abdominis (TrA). The aim of the present study was to compare the effect of instruction of PFM and TrA contraction on constriction of the levator hiatus, using 4D perineal ultrasonography. Thirteen women with pelvic organ prolapse participated in the study. Perineal ultrasound in standing position was used to assess constriction of the levator hiatus. Analyses were conducted off-line with measurements in the axial plane of minimal hiatal dimensions. The reduction of all the hiatal dimensions was significantly greater during PFM than TrA contraction. All patients had a reduction of the levator hiatus area during PFM contraction (mean reduction 24.0%; range 6.1-49.2%). In two patients, there was an increase of the levator hiatus area during TrA contraction. Instruction of PFM contraction is more effective than TrA contraction.

The quantification of levator muscle resting tone by digital assessment

The biomechanical properties of the puborectalis muscle are likely to be important for pelvic organ support. However, neither elasticity nor its clinical correlate, muscle resting tone, have received much attention to date. We therefore conducted a prospective study to test a newly developed resting tone scale for validity and reproducibility. Ninety-eight patients underwent a physical examination including prolapse staging and palpation of the levator ani. They were also assessed by 4D translabial ultrasound for levator hiatal dimensions and prolapse assessment. Resting tone was negatively associated with anterior and posterior compartment prolapse. An independent test-retest series yielded a weighted kappa of 0.55 (CI 0.44-0.66), implying "moderate" repeatability. Resting tone of the puborectalis muscle can be determined by digital palpation. It is moderately repeatable and associated with pelvic organ prolapse. Palpation of resting tone may be a useful new tool for assessing women with pelvic floor dysfunction.

OP24.12: Anal sphincter characteristics on 3D transperineal ultrasound in patients with pelvic floor problems

Objectives: To evaluate possible sonographic indicators of levator ani tissue elasticity. Methods: In this prospective study, 140 consecutive patients with varied pelvic floor problems, underwent standard urogynecological evaluation supplemented by transperineal 3D ultrasound with a 4–8 MHz transabdominal probe (GE Kretz Voluson 730 system), at rest, best Valsalva, and best pelvic floor contraction. Blinded offline analysis was performed with 4D View (GE Kretz) software. The levator ani was assessed qualitatively for widening at Valsalva or narrowing during contraction (good, poor, none), as well as measured objectively by biometry (antero-posterior diameter, leftright diameter, circumference, and area). Levator avulsion defects were quantified during contraction at the minimal hiatal dimensions using Tomographic Ultrasound Imaging (TUI). Defects were scored 0–8 for each side with a maximum score of 16, in 8 slices, 2.5 mm apart. Results: The median age was 57 (range 24–80). Avulsion defects were found in 73.2% of women, with a median TUI score of 8. Levator ballooning (hiatal area ≥25 cm2) was observed in 71.4% at Valsalva. There was a significant correlation between the presence of ballooning on Valsalva and the extent of the avulsion seen on TUI (P = 0.001). The median Valsalva to rest ratio for the levator area at the genital hiatus was 1.4 and the median contraction to rest ratio was 0.9. A Valsalva to rest ratio for levator areas greater than 1.4 was in agreement with a subjective assessment of a good Valsalva manoeuvre (P = 0.001). A contraction to rest ratio for levator areas smaller than 0.95 was in agreement with a subjective assessment of a good contraction (P = 0.002). Conclusions: There is a good correlation between levator biometry and a subjective qualitative assessment of levator function. We suggest that a Valsalva to rest ratio for areas above 1.4 and a contraction to rest ratio for areas below 0.95 may be considered as markers of levator elasticity.

Ballooning of the levator hiatus

The levator hiatus defines the 'hernial portal' through which female pelvic organ prolapse develops. Hiatal area may therefore be an independent etiological factor for this condition. In this retrospective study we defined 'normality' for hiatal area by assessing its relationship with symptoms and clinical signs of prolapse. Datasets of 544 women seen in a tertiary urogynecological unit were assessed. Patients had undergone an interview, clinical examination and three-/four-dimensional (3D/4D) pelvic floor ultrasound imaging. All analysis was performed off-line, blinded against clinical data. Information on prolapse symptoms was available for 538 women and 171 (32%) of these complained of such symptoms. There was a strong statistical relationship between hiatal dimensions, both at rest and on Valsalva maneuver, and prolapse symptoms (all P < 0.001). Receiver-operating characteristics (ROC) curve analysis yielded an area under the curve of 0.65 (95% CI, 0.60-0.70) for hiatal area at rest and 0.71 (95% CI, 0.66-0.76) for hiatal area on Valsalva. Cut-offs of 25 and 30 cm(2) on Valsalva gave sensitivities of 0.55 and 0.34 and specificities of 0.77 and 0.86, respectively, for detecting symptomatic prolapse. Similar values were obtained when significant prolapse (Grade 2 or higher) was used as the state variable. Levator hiatal area as measured by 3D translabial pelvic floor ultrasound examination is strongly associated with symptoms and clinical signs of prolapse. Based on the ROC curves that we obtained, we suggest that a hiatal area of > 25 cm(2) on Valsalva be defined as abnormal distensibility or 'ballooning' of the levator hiatus.

Pelvic Floor Function in Nulliparous Women Using Three-Dimensional Ultrasound and Magnetic Resonance Imaging

To compare biometric measures of pelvic floor function obtained using three-dimensional (3D) ultrasound and magnetic resonance imaging (MRI) in a group of nulliparous asymptomatic young women. Twenty-seven asymptomatic nulliparous volunteers were assessed prospectively, using translabial 3D ultrasound and multiplanar 3D MRI. Levator hiatal dimensions were measured in the axial plane in both modalities. All participants were imaged supine, after voiding with data acquired at rest, on maximum Valsalva and maximum pelvic floor contraction. Interobserver variability was determined for both methods. Normally distributed continuous ultrasound data were compared with equivalent MRI parameters, and intraclass correlation coefficients were used to estimate correlation between the two methods. Bland-Altman analysis was also used to estimate agreement between methods. Interobserver repeatability was fair to excellent for all parameters measured with both methods. Moderate-to-substantial agreement between methods was shown for all tested parameters (intraclass correlation coefficients 0.587-0.783). There was a systematic but nonsignificant difference between methods, in that measurements on Valsalva tended to be larger for MRI, and the poorest agreement (intraclass correlation coefficient 0.587) was found for hiatal area on Valsalva. Agreement between the two methods was moderate to substantial for all parameters except for hiatal area on Valsalva. Magnetic resonance imaging yielded higher area measurements on Valsalva, which may indicate difficulties in identifying the plane of minimal dimensions due to poorer temporal resolution compared with ultrasound imaging.

OC264: Correlation between 3D/4D translabial ultrasound and colpocystodefecography in diagnosis of posterior compartment prolapse

Valsalva. Subjective scores for pelvic floor muscle contraction were given on dynamic 3D and 4D using the standardized ICS terminology for assessment of pelvic muscle contraction (non-functioning, weak, normal or strong). Offline analysis of the datasets was undertaken using the software GE Kretz 4D View. Measurements were taken at the level of minimal hiatal dimensions using the inferior margin of the symphysis pubis as reference point on 2D and 3D datasets. On 2D ultrasound the diameter of the minimal anteroposterior (AP) hiatus, vertical displacement of the bladder neck and levator angle were measured. 3D datasets were used for obtaining AP and left–right diameter as well as area of the hiatus. Results: Complete datasets were available for 349 women. The proportional difference (value A rest–value A contraction/value A rest) between the above parameters was calculated. There were significant correlations (P < 0.001) in all parameters between women with no, weak, normal or strong contractions except for vertical bladder neck displacement. The proportional 2D AP difference between rest and contraction measured in the 2D volume seemed to be the strongest predictor, followed by 3D AP diameter and hiatal area. Conclusions: Proportional differences of the AP measurement between rest and contraction in 2D volumes is the easiest method for quantification of pelvic floor muscle contraction. Surprisingly, vertical bladder neck displacement did not seem to be significant between women with no, weak, normal or strong pelvic floor contractions.