Dynamic magnetic resonance imaging: reliability of anatomical landmarks and reference lines used to assess pelvic organ prolapse

Pubococcygeal Line Versus H-line as MR Defecography Reference for Bladder Descent

INTRODUCTION AND HYPOTHESIS

Magnetic resonance defecography imaging techniques have been used widely to study pelvic floor function and diagnose pelvic organ prolapse (POP). The aim of this study was to investigate the diagnostic accuracy of the H-line to detect bladder descent compared with the current landmark, the pubococcygeal line (PCL).

METHODS

In this retrospective cohort study, patients who underwent MR defecography in our medical center and were diagnosed with moderate to severe cystocele by radiological measurements were recruited. One rest image and one maximum evacuation image for each subject were used for the following measurements: bladder base perpendicular distance from the genital hiatus (GH), indicative of clinically significant bladder descent, PCL as the current radiological reference line, and the H-line, or minimal levator hiatus line, indicative of pelvic floor muscle and connective tissue support. Subjects were categorized as having clinically significant cystocele if the "bladder base" reached within 1 cm or lower of the GH (stage II or higher cystocele). A comparison was performed to assess differences and predictive capabilities of the reference lines relative to the GH measure.

RESULTS

Seventy subjects were included, 30 with clinically significant bladder descent based on distance to GH. Women with bladder descent were older (64.0 ± 11.8 vs 51.2 ± 15.6, p < 0.001), had increased parity (3 [1-7] vs 2 [0-5], p = 0.009), and had a bladder that descended lower than the H-line at rest (1.9 ± 0.5 vs 2.2 ± 0.4, p = 0.003) and evacuation (-2.4 ± 1.6 vs -0.7 ± 1.1, p < 0.001). Multivariate regression analysis confirmed that age, length of the H-line at evacuation, the perpendicular distances between the H-line and the lowest bladder point at rest, and the PCL to the lowest bladder point at evacuation significantly correlated with bladder descent. Receiver operating characteristic analysis was used to identify a measurement threshold to diagnose clinically significant cystocele for both measurements, bladder base to the H-line: -1.2 (80.0, 72.5) area under the curve (AUC) 0.82, and bladder base PCL: -3.3 (77.8, 79.5) AUC 0.86.

CONCLUSION

Our data support the application of using the minimal levator hiatus plane and specifically the H-line as a reliable landmark to diagnose bladder descent using MR defecography imaging.

[Imaging of the pelvic floor (MR defecography) : The surgeon's perspective]

BACKGROUND

Magnetic resonance defecography (MRD) plays a central role in diagnosing pelvic floor functional disorders by visualizing the entire pelvic floor along with pelvic organs and providing functional assessment of the defecation process. A shared understanding between radiology and surgery regarding indications and interpretation of findings is crucial for optimal utilization of MRD.

OBJECTIVES

This review aims to explain the indications for MRD from a surgical perspective and elucidate the significance of radiological findings for treatment. It intends to clarify for which symptoms MRD is appropriate and which criteria should be followed for standardized results. This is prerequisite to develop interdisciplinary therapeutic approaches.

MATERIALS AND METHODS

A comprehensive literature search was conducted, including current consensus guidelines.

RESULTS

MRD can provide relevant findings in the diagnosis of fecal incontinence and obstructed defecation syndrome, particularly in cases of pelvic floor descent, enterocele, intussusception, and pelvic floor dyssynergia. However, rectocele findings in MRD should be interpreted with caution in order to avoid overdiagnosis.

CONCLUSION

MRD findings should never be considered in isolation but rather in conjunction with patient history, clinical examination, and symptomatology since morphology and functional complaints may not always correlate, and there is wide variance of normal values. Interdisciplinary interpretation of MRD results involving radiology, surgery, gynecology, and urology, preferably in the context of pelvic floor conferences, is recommended.

Pelvic inclination correction system for magnetic resonance imaging analysis of pelvic organ prolapse in upright position

INTRODUCTION AND HYPOTHESIS

Pelvic organ prolapse quantification by means of upright magnetic resonance imaging (MRI) is a promising research field. This study determines the angle for the pelvic inclination correction system (PICS) for upright patient position, which is hypothesized to deviate from the supine PICS angle. The necessity of different PICS angles for various patient positions will also be discussed.

METHODS

Magnetic resonance scans of 113 women, acquired in an upright patient position, were used to determine the upright PICS angle, defined as the angle between the sacrococcygeal-inferior pubic point (SCIPP) line and the horizontal line. The difference and correlation between the upright and supine PICS angles were calculated using the paired Student's t-test and the Pearson's correlation coefficient (r) respectively. The effect of the difference between the upright and supine PICS angle on the measured pelvic organ extent was calculated using goniometry.

RESULTS

The mean (interquartile range) PICS angles were 29° (26-35°) for the upright and 33° (30-37°) for the supine patient position. They were significantly different (p<0.001) and very strongly correlated (r = 0.914, p<0.001). The 4° difference between the average upright and supine PICS angle results in an average underestimation of the measured cervix height of approximately 0.5 cm for patients scanned in upright position.

CONCLUSIONS

The PICS angle for the upright patient position is 29°. The use of a dedicated PICS angle for different patient positions allows for more accurate pelvic organ extent analysis in patients with prolapse.

Consensus Definitions and Interpretation Templates for Magnetic Resonance Imaging of Defecatory Pelvic Floor Disorders: Proceedings of the Consensus Meeting of the Pelvic Floor Disorders Consortium of the American Society of Colon and Rectal Surgeons, the Society of Abdominal Radiology, the International Continence Society, the American Urogynecologic Society, the International Urogynecological Association, and the Society of Gynecologic Surgeons

The Pelvic Floor Disorders Consortium (PFDC) is a multidisciplinary organization of colorectal surgeons, urogynecologists, urologists, gynecologists, gastroenterologists, radiologists, physiotherapists, and other advanced care practitioners. Specialists from these fields are all dedicated to the diagnosis and management of patients with pelvic floor conditions, but they approach, evaluate, and treat such patients with their own unique perspectives given the differences in their respective training. The PFDC was formed to bridge gaps and enable collaboration between these specialties. The goal of the PFDC is to develop and evaluate educational programs, create clinical guidelines and algorithms, and promote high quality of care in this unique patient population. The recommendations included in this article represent the work of the PFDC Working Group on Magnetic Resonance Imaging of Pelvic Floor Disorders (members listed alphabetically in Table 1). The objective was to generate inclusive, rather than prescriptive, guidance for all practitioners, irrespective of discipline, involved in the evaluation and treatment of patients with pelvic floor disorders.

Barium Defecating Proctography and Dynamic Magnetic Resonance Proctography: Their Role and Patient's Perception

Objectives:

The objectives of the study were to compare the imaging findings and patient’s perception of barium defecating proctography and dynamic magnetic resonance (MR) proctography in patients with pelvic floor disorders.

Material and Methods:

This is a prospective study conducted on patients with pelvic floor disorders who consented to undergo both barium proctography and dynamic MR proctography. Imaging findings of both the procedures were compared. Inter-observer agreement (IOA) for key imaging features was assessed. Patient’s perception of these procedures was assessed using a short questionnaire and a visual analog scale.

Results:

Forty patients (M: F =19:21) with a mean age of 43.65 years and range of 21–75 years were included for final analysis. Mean patient experience score was significantly better for MR imaging (MRI) (p < 0.001). However, patients perceived significantly higher difficulty in rectal evacuation during MRI studies (p = 0.003). While significantly higher number of rectoceles (p = 0.014) were diagnosed on MRI, a greater number of pelvic floor descent (p = 0.02) and intra-rectal intussusception (p = 0.011) were diagnosed on barium proctography. The IOA for barium proctography was substantial for identifying rectoceles, rectal prolapse and for determining M line, p < 0.001. There was excellent IOA for MRI interpretation of cystoceles, peritoneoceles, and uterine prolapse and substantial to excellent IOA for determining anal canal length and anorectal angle, p < 0.001. The mean study time for the barium and MRI study was 12 minutes and 15 minutes, respectively.

Conclusion:

Barium proctography was more sensitive than MRI for detecting pelvic floor descent and intrarectal intussusception. Although patients perceived better rectal emptying with barium proctography, the overall patient experience was better for dynamic MRI proctography.

Clinical applications of pelvic floor imaging: opinion statement endorsed by the society of abdominal radiology (SAR), American Urological Association (AUA), and American Urogynecologic Society (AUGS)

Pelvic floor dysfunction is prevalent, with multifactorial causes and variable clinical presentations. Accurate diagnosis and assessment of the involved structures commonly requires a multidisciplinary approach. Imaging is often complementary to clinical assessment, and the most commonly used modalities for pelvic floor imaging include fluoroscopic defecography, magnetic resonance defecography, and pelvic floor ultrasound. This collaboration opinion paper was developed by representatives from multiple specialties involved in care of patients with pelvic floor dysfunction (radiologists, urogynecologists, urologists, and colorectal surgeons). Here, we discuss the utility of imaging techniques in various clinical scenarios, highlighting the perspectives of referring physicians. The final draft was endorsed by the Society of Abdominal Radiology (SAR), American Urogynecologic Society (AUGS), and the American Urological Association (AUA).

Variability in utilization and techniques of pelvic floor imaging: findings of the SAR pelvic floor dysfunction disease-focused panel

Pelvic floor disorders are common and can negatively impact quality of life. Imaging of patients with pelvic floor disorders has been extremely heterogeneous between institutions due in part to variations in clinical expectations, technical considerations, and radiologist experience. In order to assess variations in utilization and technique of pelvic floor imaging across practices, the society of abdominal radiology (SAR) disease-focused panel on pelvic floor dysfunction developed and administered an online survey to radiologists including the SAR membership. Results of the survey were compared with published recommendations for pelvic floor imaging to identify areas in need of further standardization. MRI was the most commonly reported imaging technique for pelvic floor imaging followed by fluoroscopic defecography. Ultrasound was only used by a small minority of responding radiologists. The survey responses demonstrated variability in imaging utilization, patient referral patterns, imaging protocols, patient education, and interpretation and reporting of pelvic floor imaging examinations. This survey highlighted inconsistencies in technique between institutions as well as potential gaps in knowledge that should be addressed to standardize evaluation of patients with pelvic floor dysfunction.

Feasibility of a deep learning-based method for automated localization of pelvic floor landmarks using stress MR images

INTRODUCTION AND HYPOTHESIS

Magnetic resonance imaging (MRI) plays an important role in assessing pelvic organ prolapse (POP), and automated pelvic floor landmark localization potentially accelerates MRI-based measurements of POP. Herein, we aimed to develop and evaluate a deep learning-based technique for automated localization of POP-related landmarks.

METHODS

Ninety-six mid-sagittal stress MR images (at rest and at maximal Valsalva) were used for deep-learning model training and generalization testing. We randomly split our dataset into a training set of 73 images and a testing set of 23 images. One soft-tissue landmark (the cervical os [P1]) and three bony landmarks (the mid-pubic line [MPL] endpoints [P2&P3] and the sacrococcygeal inferior-pubic point [SCIPP] line endpoints [P3&P4]) were annotated by experts. We used an encoder-decoder structure to develop the deep learning model for automated localization of the four landmarks. Localization performance was assessed using the root square error (RSE), whereas the reference lines were assessed based on the length and orientation differences.

RESULTS

We localized landmarks (P1 to P4) with mean RSEs of 1.9 mm, 1.3 mm, 0.9 mm, and 3.6 mm. The mean length errors of the MPL and SCIPP line were 0.1 and -2.1 mm, and the mean orientation errors of the MPL and SCIPP line were -0.7° and -0.3°. Our method predicted each image in 0.015 s.

CONCLUSIONS

We demonstrated the feasibility of a deep learning-based approach for accurate and fast fully automated localization of bony and soft-tissue landmarks. This sped up the MR interpretation process for fast POP screening and treatment planning.

Supine magnetic resonance defecography for evaluation of anterior compartment prolapse: Comparison with upright voiding cystourethrogram

PURPOSE

To compare utility of supine Magnetic Resonance Defecography (MRD) with upright Voiding Cystourethrogram (VCUG) for evaluation of cystocele and urethral hypermobility (UHM).

METHODS

This was an IRB-approved, HIPAA-compliant, retrospective study of 51 consecutive patients with symptomatic pelvic organ prolapse (POP) and lower urinary tract symptoms who underwent both upright VCUG and supine MRD. Cystocele height was defined in centimeters with reference to the inferior edge of the pubic bone on VCUG and the pubococcygeal line on MRD. Urethral angle at rest (UAR) and during straining (UAS) was measured in degrees between the urethral axis and a vertical line at the external meatus. Pairedt-test and simple linear regression were applied to compare VCUG and MRD data sets. p <  0.05 was considered significant.

RESULTS

The mean cystocele extent was 1.58 cm lower (more inferior to the reference point) (95% CI for the mean difference: 1.21, 1.94;p < 0.0001) on MRD (-2.73 ± 1.99 cm) than on VCUG (-1.16 ± 1.75 cm). Mean UAS on MRD (72.29 ± 26.45) was 31.8 degrees higher compared to that on VCUG (40.45 ± 21.41), (95% CI for mean difference in UAS: 37.57, 26.11; p < 0.0001). Mean UAS-UAR on MRD (74.30 ± 28.50) was 58.6 degrees higher compared to that on VCUG (15.70 ± 11.27) (95% CI for mean difference in UAS-UAR 65.94, 51.26; p < 0.0001). Cystocele size was upgraded in 22 (43.3%) patients on MRD compared to VCUG. Five (9.8%) patients demonstrated UHM on VCUG; 48 (94.1%) patients demonstrated UHM on MRD. The differences between VCUG and MRD scores persisted across the range of VCUG measurements. Cystocele size was significantly larger in POP (+) patients than in POP (-) patients on MRD (p =  0.005) but not on VCUG (p =  0.06).

CONCLUSIONS

Supine MRD demonstrates significantly higher prevalence and degree of cystocele and UHM than upright VCUG, and alters the grade of bladder prolapse in a significant portion of the patient population. Cystocele size on MRD correlates with clinical presence of prolapse symptoms.

Prospective evaluation of paravaginal defect repair with and without apical suspension: a 6-month postoperative follow-up with MRI, clinical examination, and questionnaires

INTRODUCTION AND HYPOTHESIS

Paravaginal defect (PVD) has been suggested as one of the main contributors to the development of prolapse in the anterior vaginal wall (AVW). We aimed to evaluate the descent of pelvic organs, presence of vaginal H configuration, and pubococcygeus (PC) muscle defect by pelvic magnetic resonance imaging (MRI), together with subjective symptoms of prolapse, before and 6 months after PVD repair. We also aimed to evaluate risk factors of recurrence.

METHODS

Fifty women with PVD diagnosed by gynecological examination and scheduled for vaginal PVD repair were planned for enrollment. Preoperatively and 6 months postoperatively, subjective symptoms were evaluated using the International Consultation on Incontinence Questionnaire-Vaginal Symptoms (ICIQ-VS) together with MRI of the pelvis to evaluate defects in the PC muscle, vaginal shape, and pelvic organ descent.

RESULTS

Forty-six women completed the study. Twenty had PVD repair alone, whereas 26 also had concomitant surgery performed. Prolapse grade, subjective symptoms, sexual problems, and quality of life (QoL) were significantly improved at follow-up. Missing vaginal H configuration was observed in 21 women before operation and was correlated with PC muscle defect. Recurrence rate was 39%, and significantly more women with recurrence had PC muscle defects and missing H configuration.

CONCLUSION

Vaginal PVD repair alone or combined with concomitant surgery significantly reduces objective prolapse and subjective symptoms. We could not demonstrate MRI findings of missing H configuration to be a sign of PVD but, rather, a sign of defect in the PC muscle. Risk of recurrence is significantly higher in women with major PC muscle defects and missing H configuration.

Relevance of open magnetic resonance imaging position (sitting and standing) to quantify pelvic organ prolapse in women

INTRODUCTION

In pelvic organ prolapse (POP), posture and gravity impact organ position and symptom severity. The advanced magnet configuration in open magnetic resonance imaging (MRO) allows patients to be imaged when sitting and standing, as well in a conventional supine position. This study evaluated if sitting and standing MRO images are relevant as a means of improving quantification of POP because they allow differences in organ position not seen on supine imaging to be identified.

METHODS

Forty women recruited from a university urogynecology clinic had MRO imaging (0.5 T scanner) with axial and sagittal T2-weighted pelvic scans obtained when sitting, standing, and supine. Pelvic reference lines were used to quantify the degree of POP, and the relevance of imaging position on the detection of POP compared.

RESULTS

Images from 40 participants were evaluated (20 with POP and 20 asymptomatic controls). Our results indicate that the maximal extent of prolapse is best evaluated in the standing position using H line, M line, mid-pubic line, and perineal line as reference lines to determine POP.

CONCLUSIONS

MRO imaging of symptomatic patients in a standing position is relevant in the quantification of POP. Compared with supine images, standing imaging identifies that greater levels of downward movement in the anterior and posterior compartments occur, presumably under the influence of posture and gravity. In contrast, no appreciable benefit was afforded by imaging in the sitting position, which precluded use of some reference lines due to upward movement of the anorectal junction.

Magnetic resonance imaging of pelvic floor dysfunction - joint recommendations of the ESUR and ESGAR Pelvic Floor Working Group

OBJECTIVE

To develop recommendations that can be used as guidance for standardized approach regarding indications, patient preparation, sequences acquisition, interpretation and reporting of magnetic resonance imaging (MRI) for diagnosis and grading of pelvic floor dysfunction (PFD).

METHODS

The technique included critical literature between 1993 and 2013 and expert consensus about MRI protocols by the pelvic floor-imaging working group of the European Society of Urogenital Radiology (ESUR) and the European Society of Gastrointestinal and Abdominal Radiology (ESGAR) from one Egyptian and seven European institutions. Data collection and analysis were achieved in 5 consecutive steps. Eighty-two items were scored to be eligible for further analysis and scaling. Agreement of at least 80 % was defined as consensus finding.

RESULTS

Consensus was reached for 88 % of 82 items. Recommended reporting template should include two main sections for measurements and grading. The pubococcygeal line (PCL) is recommended as the reference line to measure pelvic organ prolapse. The recommended grading scheme is the "Rule of three" for Pelvic Organ Prolapse (POP), while a rectocele and ARJ descent each has its specific grading system.

CONCLUSION

This literature review and expert consensus recommendations can be used as guidance for MR imaging and reporting of PFD.

KEY POINTS

• These recommendations highlight the most important prerequisites to obtain a diagnostic PFD-MRI. • Static, dynamic and evacuation sequences should be generally performed for PFD evaluation. • The recommendations were constructed through consensus among 13 radiologists from 8 institutions.

Prevalence of dynamic magnetic resonance imaging-identified pelvic organ prolapse in pre- and postmenopausal women without clinically evident pelvic organ descent

Background Dynamic magnetic resonance imaging (dMRI) is an imaging tool that can be used to evaluate and stage pelvic organ prolapse (POP). Greater understanding of the incidental detection of POP in asymptomatic patients is needed. Purpose To evaluate the prevalence of dMRI-detected POP in pre-and postmenopausal women who were imaged for reasons unrelated to pelvic floor dysfunction. Material and Methods A total of 227 women who had diagnoses that did not include POP underwent abdominal/pelvic dMRI. Patients with a positive gynecological examination for or a clinical history of POP ( n = 11), hysterectomy ( n = 4), or gynecologic-oncology surgery ( n = 2) were excluded, as well as patients who were unable to strain during MRI ( n = 11). A total of 199 patients without visible prolapse were enrolled in the study. An H-line, M-line, pubococcygeal line (PCL), and mid-pubic line (MPL) were used to detect and grade prolapse. Results The prevalence of dMRI-identified POP was higher in postmenopausal subjects. The PCL led to a greater frequency of prolapse detection than the MPL. The frequency of middle compartment descent was similar regardless of whether the PCL or MPL was used as a reference line. There was a higher incidence of prolapse in the posterior compartment. Using an H-line and PCL as references, the anterior and posterior compartments were found to significantly differ between pre- and postmenopausal subjects. The MRI parameters that were used to define POP were not correlated with parity, vaginal birth, BMI, or fetal birth weight. With respect to the MPL, age was correlated with both the presence of an elongated H-line and with descent. Conclusion Dynamic MRI identified incidental pelvic organ prolapse in asymptomatic patients. The prevalence of dMRI-detected POP was higher in postmenopausal women without visible prolapse. These findings suggest the need for further studies to identify how to modify the currently used dMRI thresholds for postmenopausal women.

ACR Appropriateness Criteria pelvic floor dysfunction

Pelvic floor dysfunction is a common and potentially complex condition. Imaging can complement physical examination by revealing clinically occult abnormalities and clarifying the nature of the pelvic floor defects present. Imaging can add value in preoperative management for patients with a complex clinical presentation, and in postoperative management of patients suspected to have recurrent pelvic floor dysfunction or a surgical complication. Imaging findings are only clinically relevant if the patient is symptomatic. Several imaging modalities have a potential role in evaluating patients; the choice of modality depends on the patient's symptoms, the clinical information desired, and the usefulness of the test. The ACR Appropriateness Criteria are evidence-based guidelines for specific clinical conditions; they are reviewed every 3 years by a multidisciplinary expert panel. The guideline development and review include an extensive analysis of current medical literature from peer-reviewed journals, and the application of a well-established consensus methodology (modified Delphi) to rate the appropriateness of imaging and treatment procedures by the panel. In instances in which evidence is lacking or not definitive, expert opinion may be used to recommend imaging or treatment.

Dynamic Magnetic Resonance Imaging and pelvic floor disorders: how and when?

Pelvic Floor Disorders (PFD) are a major public health problem in the world and decrease seriously the patient's quality of life. In case of recurrence after surgery or complex prolapse, imaging techniques can be used. Dynamic MRI, introduced in the early 1990s, offers information of the four compartments of the pelvis with a high resolution and a direct visualization of muscles and fascias in multiple planes. But for a practical use, such an expensive exam should be well correlated to symptoms and clinical examination or change surgical approach. The aim of our review was to precise the evidence regarding techniques, and indication of dynamic MRI in the assessment of pelvic floor disorders in daily practice. The first part is a review of available studies on methods of carrying out the dynamic MRI. The second part consists on the comparison of dynamic MRI to other assessment methods in case of pelvic floor disorders. Results emphasize the lack of strong level studies about the interest of dynamic MRI in the diagnosis and surgical management of pelvic organ prolapse. Although dynamic MRI appears highly reproducible between examiners, especially for the anterior compartment, its correlation with the degree of prolapse or the symptoms appears low. The most interesting field of application seems the detection of levator ani (LA) avulsion with a higher risk of prolapse and recidive in case of LA defects. More prospective, randomized, comparative studies have to be done.

Dynamic magnetic resonance imaging before and 6 months after laparoscopic sacrocolpopexy

INTRODUCTION AND HYPOTHESIS

The objective of this study was to correlate dynamic magnetic resonance imaging (MRI) with Pelvic Organ Prolapse Quantification (POP-Q) measurements and pelvic floor symptoms in order to determine the value of dynamic MRI for evaluating vaginal vault prolapse both before and 6 months after laparoscopic sacrocolpopexy.

METHODS

This was a prospective, single-center cohort study in 43 patients who underwent a modified laparoscopic sacrocolpopexy/hysteropexy operation using bone-anchor fixation and synthetic mesh. The study included dynamic MRI, POP-Q staging, and validated questionnaires before and 6 months after laparoscopic sacrocolpopexy. To assess MRI data, the pubococcygeal reference line and specifically defined anatomical landmarks for the separate compartments were used. Differences between pre- and postoperative measurements were evaluated with the Wilcoxon signed-rank test, and correlations at the 0.05 level were considered to be significant (Pearson correlation, two tailed).

RESULTS

At 6 months, a statistically significant improvement was seen in POP-Q staging for all compartments. Dynamic MRI measurements only revealed a significant improvement after surgery for the apical compartment. The correlation between (changes in) MRI measurements, POP-Q measurements, and validated questionnaires was poor.

CONCLUSIONS

The value of dynamic MRI for evaluating and documenting changes in vaginal vault support and position after laparoscopic sacrocolpopexy is limited due to the poor correlation with both POP-Q staging and pelvic floor symptoms.

Magnetic resonance imaging of the pelvic floor: from clinical to biomechanical imaging

This article reviews the current role of magnetic resonance imaging in the study of the pelvic floor anatomy and pelvic floor dysfunction. The application of static and dynamic magnetic resonance imaging in the clinical context and for biomechanical simulation modeling is assessed, and the main findings are summarized. Additionally, magnetic resonance-based diffusion tensor imaging is presented as a potential tool to evaluate muscle fiber morphology. In this article, focus is set on pelvic floor muscle damage related to urinary incontinence and pelvic organ prolapse, sometimes as a consequence of vaginal delivery. Modeling applications that evaluate anatomical and physiological properties of pelvic floor are presented to further illustrate their particular characteristics. Finally, finite element method is described as a method for modeling and analyzing pelvic floor structures' biomechanical performance, based on material and behavioral properties of the tissues, and considering pressure loads that mimic real-life conditions such as active contraction or Valsalva maneuver.

On pelvic reference lines and the MR evaluation of genital prolapse: a proposal for standardization using the Pelvic Inclination Correction System

Five midsagittal pelvic reference lines have been employed to quantify prolapse using MRI. However, the lack of standardization makes study results difficult to compare. Using MRI scans from 149 women, we demonstrate how use of existing reference lines can systematically affect measurements in three distinct ways: in oblique line systems, distances measured to the reference line vary with antero-posterior location; soft issue-based reference lines can underestimate organ movement relative to the pelvic bones; and systems defined relative to the MR scanner are affected by intra- and interindividual differences in the pelvic inclination angle at rest and strain. Thus, we propose a standardized approach called the Pelvic Inclination Correction System (PICS). Based on bony structures and the body axis, the PICS system corrects for variation in pelvic inclination, at rest of straining, and allows for the standardized measurement of organ displacement in the direction of prolapse.

Dynamic MRI (dMRI) as a guide to therapy in children and adolescents with persistent full thickness rectal prolapse: a single centre review

INTRODUCTION

Full thickness rectal prolapse (FTRP) tends to be self-limiting in children and is usually managed expectantly. However, it may persist and therefore requires surgical correction. There is no consensus upon operative management, and no one procedure has uniformly good outcomes. The aim of this study was to determine whether pre-operative diagnostic dMRI findings might help identify the operative approach best suited to the anatomical abnormality of the individual child.

METHODS

A retrospective review of ten children with persistent FTRP who had been evaluated pre-operatively with dMRI between 2002 and 2010 was performed. In this preliminary work, MRI findings were not used to direct surgical management. Data collected included: age at presentation, underlying medical conditions, timing and findings of dMRI (specifically, descent of rectum from pubococcygeal (PC) line on straining), timing and type of surgery, surgical outcomes, and length of follow-up.

RESULTS

Ten children (two female) with a median age of 11 years 2 months (range 8-15 years) with FTRP refractory to conservative treatment underwent diagnostic pre-operative dMRI. Median perineal descent from PC line on straining during dMRI was 3.5 cm (range 1-4 cm). Three of the seven children with severe descent initially underwent a Delorme's procedure, and all required surgical revision. Five with severe descent and one with moderate descent achieved a cure following rectopexy. Two patients with mild descent underwent a Delorme's procedure. One achieved a cure, and the other developed recurrence. Of the ten patients, seven had no prolapse at the last clinic review, and three have persisting symptoms. Median follow-up was 3.5 years (range 1-6).

CONCLUSION

The findings from this small study favour rectal suspension techniques for surgical management of moderate to severe perineal descent on dMRI. Delorme's procedure should only be applied to those with mild descent. Pre-operative dMRI assessment may have a potential role in guiding surgical intervention for children. However, future prospective studies will be required to confirm this assertion.

Dynamic magnetic resonance imaging to quantify pelvic organ prolapse: reliability of assessment and correlation with clinical findings and pelvic floor symptoms

Introduction and hypothesis

The aim of this study was to assess the interobserver agreement of magnetic resonance imaging (MRI)-based staging of pelvic organ prolapse (POP) and to quantify associations between MRI-based POP staging, findings at pelvic examination, and pelvic floor symptoms.

Methods

This was a cross-sectional study of ten symptomatic POP patients, ten symptomatic patients without POP, and ten nulliparous asymptomatic women. Three different observers performed MRI-based POP staging using the pubococcygeal line (PCL), midpubic line (MPL), perineal line, and H line as references.

Results

The interobserver agreement of MRI-based staging of the anterior and middle compartment was good to excellent. In symptomatic women without prolapse, MRI-based and pelvic-examination-based POP staging were poorly correlated. In none of the women were MRI-based POP Quantification (POP-Q) staging and pelvic floor symptoms strongly associated.

Conclusion

The interobserver agreement of MRI-based POP staging is excellent, but the added clinical value of such staging is questionable due to poor association with clinical findings and pelvic floor symptoms.

Levator ani subtended volume: a novel parameter to evaluate levator ani muscle laxity in pelvic organ prolapse

OBJECTIVE

We describe a new parameter based on magnetic resonance 3-dimensional (3D) reconstructions proposed to evaluate levator ani muscle (LAM) laxity in women with pelvic organ prolapse (POP).

STUDY DESIGN

This is an institutional review board-approved, retrospective chart review of 35 women with POP, stages I-IV. The 3D Slicer software package was used to perform 2-dimensional and 3D measurements and the levator ani subtended volume (LASV) was described. Basically, the LASV represents the volume contained by LAM between 2 planes, which coincides with pubococcygeal line and H line. Correlations among measurements, ordinal POP stages, POP Quantification (POPQ) individual measurements, and validated questionnaires were performed.

RESULTS

The LASV differentiated major (III and IV) from minor (I and II) POPQ stages, which positively correlated to POP stages and POPQ individual measurements.

CONCLUSION

The LASV is a promising parameter to evaluate the LAM laxity.

MRI diagnosis of pelvic organ prolapse compared with clinical examination

RATIONALE AND OBJECTIVES

The aims of this study were to determine agreement between clinical examination and magnetic resonance imaging (MRI) (rectal contrast and noncontrast MRI) for pelvic organ prolapse using both the pubococcygeal line (PCL) and the midpubic line (MPL) and to assess the relationship between measurements performed relative to each line.

MATERIALS AND METHODS

Dynamic MRI exams in 88 women (with rectal contrast, n = 39; noncontrast, n = 49) were evaluated, followed by review of clinical exam notes. Agreement between clinical exam and MRI and the difference between PCL and MPL measurements were evaluated.

RESULTS

Agreement of rectal contrast MRI with clinical exam was 79% for PCL and 85% for MPL (P = .17) for cystoceles, 50% for PCL and 59% for MPL (P = .20) for vaginal prolapse, 56% for PCL for enteroceles, and 61% for rectoceles. Agreement of noncontrast MRI with clinical exam was 67% for PCL and 78% for MPL (P = .19) for cystoceles, 58% for PCL and 71% for MPL (P = .10) for vaginal prolapse, 65% for enteroceles, and 40% for rectoceles. The average difference between the PCL and the MPL was 3.12 ± 0.24 cm at the bladder base and 4.88 ± 0.37 cm at the vaginal apex.

CONCLUSIONS

Agreement of MRI with clinical exam was highest for cystoceles. There was no significant difference in agreement using the MPL or PCL, suggesting that either line can be used on MRI. The average differences between the PCL and MPL at the bladder base and vaginal apex were approximately 3 and 5 cm, respectively.

Dynamic magnetic resonance imaging of pelvic organ prolapse: recent research progress

Pelvic organ prolapse (POP) refers to herniation of pelvic organs caused by the weak pelvic floor support structures. Magnetic resonance imaging (MRI) is a non-radioactive, non-invasive, fast, comprehensive, high-resolution imaging technique that has strong soft tissue contrast and can clearly show the changes of muscles and fascia structures of pelvic floor to the resting and dynamic position. It can help understand the state of pelvic organizations and provide objective imaging data for the clinical diagnosis. Dynamic MRI is commonly used for the diagnosis of bladder prolapse and swelling, uterine and vaginal prolapse, rectal prolapse and enterocele. Currently, there are no unified diagnostic criteria for POP in China. Although the US HMO system is frequently used for assessing the degree of POP, it needs to be further explored whether this system is fit for the Chinese population. In short, dynamic MRI permits a comprehensive evaluation of pelvic organ prolapse. It is an important way to study the living anatomy, shape and movement of pelvic floor. In addition to clinical evaluations, dynamic MRI (especially dynamic MRI defecography) plays a role in guiding the interdisciplinary treatment of pelvic floor dysfunction.

Dynamic MR defecography with an open-configuration, low-field, tilting MR system in patients with pelvic floor disorders

PURPOSE

This study was undertaken to explore the capabilities of an open-configuration, low-field, tilting, magnetic resonance (MR) system for investigating pelvic floor disorders and to compare the results obtained with the patient in the semiorthostatic and supine positions.

MATERIALS AND METHODS

Eighteen female patients with a diagnosis of pelvic floor disorder (physical examination and conventional defecography) underwent dynamic MR defecography (MRD) with a 0.25-T tilting MR system (G-scan, Esaote). Images were obtained after administration of contrast agent into the rectum, bladder and vagina in both the orthostatic and supine positions. Three-dimensional T2-weighted hybrid contrast-enhanced (HYCE) sequences and dynamic T1-weighted gradient echo (GE) sequences were acquired at rest, during maximal contraction of the anal sphincter, straining and defecation.

RESULTS

Good image quality was obtained in 15/18 patients; three presented severe artefacts due to motion, and three had incontinence, which hampered the functional studies. Better anatomical detail was obtained with MRD compared with conventional defecography. Three prolapses were observed in the semiorthostatic position only, and seven were found to be more severe in the orthostatic than in the supine position.

CONCLUSIONS

Dynamic MRD with an open-configuration, low-field, tilting MR system is a feasible and promising tool for studying the pelvic floor. Larger series are necessary to assess its real diagnostic value.

MRI pelvic landmark angles in the assessment of apical pelvic organ prolapse

PURPOSE

The aim of the study was to evaluate the utility of magnetic resonance imaging (MRI) pelvic landmark angles and lines in the assessment of apical vault prolapse.

METHODS

Seventeen women were evaluated as part of a prospective surgical trial. Baseline data are presented as a pilot study of the utility of MRI in addition to this evaluation of 6 nulliparous volunteers without prolapse and 11 parous women with symptomatic ≥ stage II uterine prolapse. Each patient underwent assessment for pelvic organ prolapse quantification (POPQ) and pelvic MRI. Pelvic landmark angles and lines were measured. Mann-Whitney Rank sum test and Spearman's Rank order correlation test were used to assess agreement.

RESULTS

Women with prolapse had a significantly larger h angle, g angle, and e angle at rest than those without prolapse. Correlation between apical vault descent was measured clinically by POPQ point C with MRI measurements: h angle (r = 0.61, p = 0.01), g angle (r = 0.64, p = 0.005), and e angle (r = 0.62, p = 0.007).

CONCLUSION

MRI measurements of pelvic landmark angles reliably differentiate between women with and without uterine prolapse and correlate best with POPQ point C.

Perineal descent and patients' symptoms of anorectal dysfunction, pelvic organ prolapse, and urinary incontinence

Introduction and hypothesis

The aim of this dynamic magnetic resonance (MR) imaging study was to assess the relation between the position and mobility of the perineum and patients’ symptoms of pelvic floor dysfunction.

Methods

Patients’ symptoms were measured with the use of validated questionnaires. Univariate logistic regression analyses were used to study the relationship between the questionnaires domain scores and the perineal position on dynamic MR imaging, as well as baseline characteristics (age, body mass index, and parity).

Results

Sixty-nine women were included in the analysis. Only the domain score genital prolapse was associated with the perineal position on dynamic MR imaging. This association was strongest at rest.

Conclusions

Pelvic organ prolapse symptoms were associated with the degree of descent of the perineum on dynamic MR imaging. Perineal descent was not related to anorectal and/or urinary incontinence symptoms.

Symptoms of pelvic floor dysfunction are poorly correlated with findings on clinical examination and dynamic MR imaging of the pelvic floor

Introduction and hypothesis

The aim of the study was to determine whether patients’ symptoms agree with findings on clinical examination and dynamic MR imaging of the pelvic floor.

Methods

Symptoms of pelvic organ dysfunction were measured with the use of three validated questionnaires. The domain scores were compared with POP-Q and dynamic MR imaging measurements. The Spearman’s rank correlation coefficient (r_s) was used to assess agreement.

Results

Only the domain score genital prolapse was significantly correlated in the positive direction with the degree of pelvic organ prolapse as assessed by POP-Q and dynamic MR imaging (r_s = 0.64 and 0.27, respectively), whereas the domain score urinary incontinence was inversely correlated (r_s = −0.32 and −0.35, respectively).

Conclusions

The sensation or visualization of a bulge in the vagina was the only symptom which correlated positively with the degree of pelvic organ prolapse, and clinical examination and dynamic MR imaging showed similar correlation in this respect.