Pelvic floor imaging

Imaging modalities for the detection of posterior pelvic floor disorders in women with obstructed defaecation syndrome

BACKGROUND

Obstructed defaecation syndrome (ODS) is difficulty in evacuating stools, requiring straining efforts at defaecation, having the sensation of incomplete evacuation, or the need to manually assist defaecation. This is due to a physical blockage of the faecal stream during defaecation attempts, caused by rectocele, enterocele, intussusception, anismus or pelvic floor descent. Evacuation proctography (EP) is the most common imaging technique for diagnosis of posterior pelvic floor disorders. It has been regarded as the reference standard because of extensive experience, although it has been proven not to have perfect accuracy. Moreover, EP is invasive, embarrassing and uses ionising radiation. Alternative imaging techniques addressing these issues have been developed and assessed for their accuracy. Because of varying results, leading to a lack of consensus, a systematic review and meta-analysis of the literature are required.

OBJECTIVES

To determine the diagnostic test accuracy of EP, dynamic magnetic resonance imaging (MRI) and pelvic floor ultrasound for the detection of posterior pelvic floor disorders in women with ODS, using latent class analysis in the absence of a reference standard, and to assess whether MRI or ultrasound could replace EP. The secondary objective was to investigate differences in diagnostic test accuracy in relation to the use of rectal contrast, evacuation phase, patient position and cut-off values, which could influence test outcome.

SEARCH METHODS

We ran an electronic search on 18 December 2019 in the Cochrane Library, MEDLINE, Embase, SCI, CINAHL and CPCI. Reference list, Google scholar. We also searched WHO ICTRP and clinicaltrials.gov for eligible articles. Two review authors conducted title and abstract screening and full-text assessment, resolving disagreements with a third review author.

SELECTION CRITERIA

Diagnostic test accuracy and cohort studies were eligible for inclusion if they evaluated the test accuracy of EP, and MRI or pelvic floor ultrasound, or both, for the detection of posterior pelvic floor disorders in women with ODS. We excluded case-control studies. If studies partially met the inclusion criteria, we contacted the authors for additional information.

DATA COLLECTION AND ANALYSIS

Two review authors performed data extraction, including study characteristics, 'Risk-of-bias' assessment, sources of heterogeneity and test accuracy results. We excluded studies if test accuracy data could not be retrieved despite all efforts. We performed meta-analysis using Bayesian hierarchical latent class analysis. For the index test to qualify as a replacement test for EP, both sensitivity and specificity should be similar or higher than the historic reference standard (EP), and for a triage test either specificity or sensitivity should be similar or higher. We conducted heterogeneity analysis assessing the effect of different test conditions on test accuracy. We ran sensitivity analyses by excluding studies with high risk of bias, with concerns about applicability, or those published before 2010. We assessed the overall quality of evidence (QoE) according to GRADE.

MAIN RESULTS

Thirty-nine studies covering 2483 participants were included into the meta-analyses. We produced pooled estimates of sensitivity and specificity for all index tests for each target condition. Findings of the sensitivity analyses were consistent with the main analysis. Sensitivity of EP for diagnosis of rectocele was 98% (credible interval (CrI)94%-99%), enterocele 91%(CrI 83%-97%), intussusception 89%(CrI 79%-96%) and pelvic floor descent 98%(CrI 93%-100%); specificity for enterocele was 96%(CrI 93%-99%), intussusception 92%(CrI 86%-97%) and anismus 97%(CrI 94%-99%), all with high QoE. Moderate to low QoE showed a sensitivity for anismus of 80%(CrI 63%-94%), and specificity for rectocele of 78%(CrI 63%-90%) and pelvic floor descent 83%(CrI 59%-96%). Specificity of MRI for diagnosis of rectocele was 90% (CrI 79%-97%), enterocele 99% (CrI 96%-100%) and intussusception 97% (CrI 88%-100%), meeting the criteria for a triage test with high QoE. MRI did not meet the criteria to replace EP. Heterogeneity analysis showed that sensitivity of MRI performed with evacuation phase was higher than without for rectocele (94%, CrI 87%-98%) versus 65%, CrI 52% to 89%, and enterocele (87%, CrI 74%-95% versus 62%, CrI 51%-88%), and sensitivity of MRI without evacuation phase was significantly lower than EP. Specificity of transperineal ultrasound (TPUS) for diagnosis of rectocele was 89% (CrI 81%-96%), enterocele 98% (CrI 95%-100%) and intussusception 96% (CrI 91%-99%); sensitivity for anismus was 92% (CrI 72%-98%), meeting the criteria for a triage test with high QoE. TPUS did not meet the criteria to replace EP. Heterogeneity analysis showed that sensitivity of TPUS performed with rectal contrast was not significantly higher than without for rectocele(92%, CrI 69%-99% versus 81%, CrI 58%-95%), enterocele (90%, CrI 71%-99% versus 67%, CrI 51%-90%) and intussusception (90%, CrI 69%-98% versus 61%, CrI 51%-86%), and was lower than EP. Specificity of endovaginal ultrasound (EVUS) for diagnosis of rectocele was 76% (CrI 54%-93%), enterocele 97% (CrI 80%-99%) and intussusception 93% (CrI 72%-99%); sensitivity for anismus was 84% (CrI 59%-96%), meeting the criteria for a triage test with very low to moderate QoE. EVUS did not meet the criteria to replace EP. Specificity of dynamic anal endosonography (DAE) for diagnosis of rectocele was 88% (CrI 62%-99%), enterocele 97% (CrI 75%-100%) and intussusception 93% (CrI 65%-99%), meeting the criteria for a triage test with very low to moderate QoE. DAE did not meet the criteria to replace EP. Echodefaecography (EDF) had a sensitivity of 89% (CrI 65%-98%) and specificity of 92% (CrI 72%-99%) for intussusception, meeting the criteria to replace EP but with very low QoE. Specificity of EDF for diagnosis of rectocele was 89% (CrI 60%-99%) and for enterocele 97% (CrI 87%-100%); sensitivity for anismus was 87% (CrI 72%-96%), meeting the criteria for a triage test with low to very low QoE.

AUTHORS' CONCLUSIONS

In a population of women with symptoms of ODS, none of the imaging techniques met the criteria to replace EP. MRI and TPUS met the criteria of a triage test, as a positive test confirms diagnosis of rectocele, enterocele and intussusception, and a negative test rules out diagnosis of anismus. An evacuation phase increased sensitivity of MRI. Rectal contrast did not increase sensitivity of TPUS. QoE of EVUS, DAE and EDF was too low to draw conclusions. More well-designed studies are required to define their role in the diagnostic pathway of ODS.

Antenatal and postnatal assessment of pelvic floor muscles in continent and incontinent primigravida women

INTRODUCTION AND HYPOTHESIS

Reduced pelvic floor muscle (PFM) strength and thickness are considered critical factors in pregnancy-related stress urinary incontinence. Various methods have been evaluated for the measurement of these two factors, but validity needs to be well established. The objective was to assess the strength and thickness of pelvic floor muscles of continent and incontinent primigravida women using the digital method and transperineal ultrasound, and to study the correlation between the two methods.

METHODS

Assessment of pelvic floor muscle strength and thickness using digital assessment and transperineal ultrasound antepartum and postpartum in 100 primigravida women.

RESULTS

A total of 100 primigravida women with 46 in the study group (incontinent) and 54 in the control group (continent) were assessed. PFM strength was lower in incontinent women, with a score of 3 or less in 82.61% (38 out of 46) compared with a score of 4 or more in 98.15% of continent women (53 out of 54; p < 0.0001) antenatally, as well as postnatally, with 81.25% of the incontinent women (26 out of 32), with a score of 3 or less compared with 100% of continent women (24 out of 24), with a score of 4 or more (p < 0.0001). The PFM thickness in the incontinent group compared with the continent group at relaxation was 5.94 ± 0.51 mm and 6.64 ± 0.26 mm (p < 0.0001) antenatally and 5.98 ± 0.55 mm and 6.69 ± 0.23 mm (p < 0.0001) postnatally; at contraction it was 7.29 ± 0.56 mm and 8.70 ± 0.24 mm (p < 0.0001) antenatally and 7.39 ± 0.56 mm and 8.77 ± 0.20 mm (p < 0.0001) postnatally. The Pearson correlation coefficient for the two methods during the antenatal and postpartum periods was 0.864 and 0.743 respectively, suggestive of a positive correlation between the two methods.

CONCLUSIONS

Pelvic floor muscle strength, as well as thickness, is significantly lower among the incontinent group than among the continent group, both during antenatal and during the postnatal period.

Dynamic fluoroscopic defecography: updates on rationale, technique, and interpretation from the Society of Abdominal Radiology Pelvic Floor Disease Focus Panel

Whether used as the primary diagnostic test or reserved as a problem-solving examination, fluoroscopic defecography (FD) remains an important tool in the workup and treatment of defecatory disorders. FD is a well-established, simple, and rapid examination that most closely resembles the actual process and position that a patient uses to enable defecation and provides both qualitative and quantitative information on the defecatory process. FD is indicated when re-creating the act of defecation is necessary, especially in patients with symptoms of obstructed defecation and where symptoms do not correlate with prior examinations such as MRI. Also, FD may help the patient understand the severity of their condition, better informing them of the structural and functional pathology, and aid in discussions with the surgeon regarding plans for treating their complex pelvic floor and defecatory problems. This review provides an up-to-date, comprehensive summary of FD and describes the indications for, techniques of, and common pathology encountered.

Placement of a fine-bore rectal balloon catheter in the anal canal does not affect anal sphincter pressures: improving our understanding of physiological function with anal acoustic reflectometry

AIM

The recto-anal inhibitory reflex (RAIR) is currently measured using anorectal manometry catheters, which may distort the anal canal. Anal acoustic reflectometry (AAR) is considered a catheter-free technique for evaluating the physiological function of the anal canal; however, it has yet to be used to elicit the RAIR. For the RAIR to be measured with AAR, the effect of placing an additional rectal balloon catheter on the measured AAR parameters needs to be investigated: that is the aim of this work.

METHOD

Patients aged over 18 years attending hospital for the investigation of pelvic floor disorders were included. AAR parameters were obtained before and after a rectal balloon catheter was placed alongside the AAR catheter. The following parameters were measured: opening pressure (Op, cmH₂ O), opening elastance (Oe, cmH₂ O/mm² ), closing pressure (Cp, cmH₂ O), closing elastance (Ce, cmH₂ O/mm² ), hysteresis (Hys, %), squeeze opening pressure (SqOp, cmH₂ O) and squeeze opening elastance (SqOe, cmH₂ O/mm² ).

RESULTS

Thirty-five patients were included in the analysis, of whom 28 were women. The median age was 58 years. Comparison of median AAR parameters before and after catheter placement showed no significant difference: Op (36.36 vs 33.42, P = 0.09), Oe (1.27 vs 1.39, P = 0.19), Cp (18.62 vs 19.73, P = 0.13), Ce (1.2 vs 1.28, P = 0.33), Hys (41.08 vs 40.11, P = 0.17), SqOp (81.85 vs 81.65, P = 0.93) and SqOe (1.44 vs 1.49, P = 0.55).

DISCUSSION

Placement of a rectal balloon catheter alongside the AAR catheter has no significant effect on the measured AAR parameters. The results of this study add to the fundamental basic science and understanding of the physiological function of the anal canal.

Dynamic magnetic resonance imaging of the female pelvic floor-a pictorial review

Pelvic floor dysfunctions represent a range of functional disorders that frequently occur in adult women, carrying a significant burden on the quality of life, and its incidence tends to increase attending to the expected aging of the population. Pelvic floor dysfunctions can manifest as incontinence, constipation, and prolapsed pelvic organs. Since pelvic floor weakness is frequently generalized and clinically underdiagnosed, imaging evaluation is of major importance, especially prior to surgical correction. Given some interobserver variability of soft-tissue measurements, MR defecography allows a noninvasive, radiation-free, multiplanar dynamic evaluation of the three pelvic compartments simultaneously and with high spatial and temporal resolution. Both static/anatomic and dynamic/functional findings are important, since pelvic disorders can manifest as whole pelvic floor weakness/dysfunction or as an isolated or single compartment disorder. Imaging has a preponderant role in accessing pelvic floor disorders, and dynamic MR defecography presents as a reliable option, being able to evaluate the entire pelvic floor for optimal patient management before surgery. The purpose of this article is to address the female pelvic anatomy and explain the appropriate MR Defecography protocol, along with all the anatomic points, lines, angles, and measurements needed for a correct interpretation, to later focus on the different disorders of the female pelvic floor, illustrated with MR defecography images, highlighting the role of this technique in accessing these pathologic conditions.

Defecography: An Overview of Technique, Interpretation, and Impact on Patient Care

Pelvic floor and defecatory dysfunction are common in the female patient population. When combined with physical examination, barium defecography allows for accurate and expanded assessment of the underlying pathology and helps to guide future intervention. Understanding the imaging findings of barium defecography in the spectrum of pathology of the anorectum and pelvic floor allows one to appropriately triage and treat patients presenting with defecatory dysfunction.

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.

The importance of uterosacral ligament anatomy in overactive bladder: A preliminary study

Objective:

To evaluate whether uterosacral ligament (USL) thickness measured using magnetic resonance imaging (MRI) was associated with overactive bladder (OAB) in otherwise healthy women.

Materials and Methods:

The study comprised 27 women with OAB and 27 healthy women (control group) who were followed up at the Obstetrics and Gynecology Department of a tertiary referral center. All subjects were evaluated using pelvic MRI to determine the transverse USL thickness. These measurements were compared between the two groups. p values less than 0.05 were considered statistically significant.

Results:

The mean age of women in the OAB and control groups were 43.88±9.36 years and 39.92±5.36 years, respectively. The mean body mass index in the OAB group was 29.77±4.82 kg/m² and 27.49±3.44 kg/m² in the control group. In the comparison of Pelvic Organ Prolapse Quantification system stages between the groups, no statistically significant relationship was determined. In the OAB group, the mean right USL thickness was 2.04±0.34 mm, and the mean left USL was 2.04±0.52 mm. In the control group, the mean right USL thickness was 2.17±0.47 mm, and the mean left USL was 2.09±0.51 mm. There were no statistically significant differences in terms of USL thickness between the OAB and control groups (p>0.05).

Conclusion:

No previous studies have been identified in the literature that have investigated the relationship between USL thicknesses and urinary incontinence. In the present study, no significant relationship could be demonstrated between right and left USL thicknesses of the OAB and control groups. This was a preliminary study, and further research with larger sample sizes is required to reach a final conclusion.

Practical guide to dynamic pelvic floor MRI

Pelvic floor dysfunction encompasses a spectrum of functional disorders that result from impairment of the ligaments, fasciae, and muscles supporting the pelvic organs. It is a prevalent disorder that carries a lifetime risk over 10% for undergoing a surgical repair. Pelvic floor weakness presents as a wide range of symptoms, including pain, pelvic pressure or bulging, urinary and fecal incontinence, constipation, and sexual dysfunction. A correct diagnosis by clinical examination alone can be challenging, particularly in cases involving multiple compartments. Magnetic resonance imaging (MRI) allows noninvasive, radiation-free, high soft-tissue resolution evaluation of all three pelvic compartments, and has proved a reliable technique for accurate diagnosis of pelvic floor dysfunction. MR defecography with steady-state sequences allows detailed anatomic and functional evaluation of the pelvic floor. This article provides an overview of normal anatomy and function of the pelvic floor and discusses a practical approach to the evaluation of imaging findings of pelvic floor relaxation, pelvic organ prolapse, fecal incontinence, and obstructed defecation.

LEVEL OF EVIDENCE

5 Technical Efficacy: Stage 2 J. Magn. Reson. Imaging 2018;47:1155-1170.

Anatomy and mechanical properties of the anal sphincter muscles in healthy senior volunteers

BACKGROUND

A large proportion of age-related fecal incontinence is attributed to weakness or degeneration of the muscles composing the anal continence organ. However, the individual role of these muscles and their functional interplay remain poorly understood.

METHODS

This study employs a novel technique based on the combination of MR imaging and FLIP measurements (MR-FLIP) to obtain anatomical and mechanical information simultaneously. Unlike previous methods used to assess the mechanics of the continence organ, MR-FLIP allows inter-individual comparisons and statistical analysis of the sphincter morpho-mechanical parameters. The anatomy as well as voluntary and involuntary mechanical properties of the anal continence organ were characterized in 20 healthy senior volunteers.

RESULTS

Results showed that the external anal sphincter (EAS) forms a funnel-like shape with wall thickness increasing by a factor of 2.5 from distal (6 ± 0 mm) to proximal (15 ± 3 mm). Both voluntary and involuntary mechanical properties in this region correlate strongly with the thickness of the muscle. The positions of least compliance and maximal orifice closing were both located toward the proximal EAS end. In addition, maximal contraction during squeeze maneuvers was reached after 2 s, but high muscle fatigue was measured during a 7 s holding phase, corresponding to about 60% loss of the energy produced by the muscles during the contraction phase.

CONCLUSIONS

This work reports baseline parameters describing the morpho-mechanical condition of the sphincter muscle of healthy elderly volunteers. New parameters were also proposed to quantify the active properties of the muscles based on the mechanical energy associated with muscle contraction and fatigue. This information could be used to assess patients suffering from AI or for the design of novel implants.

The clinical value of magnetic resonance defecography in males with obstructed defecation syndrome

BACKGROUND

The aim of the present study was to assess the relationship between symptoms of obstructed defecation and findings on magnetic resonance (MR) defecography in males with obstructed defecation syndrome (ODS).

METHODS

Thirty-six males with ODS who underwent MR defecography at our institution between March 2013 and February 2016 were asked in a telephone interview about their symptoms and subsequent treatment, either medical or surgical. Patients were divided into 2 groups, one with anismus (Group 1) and one with prolapse without anismus (Group 2). The interaction between ODS type and symptoms with MR findings was assessed by multivariate analysis for categorical data using a hierarchical log-linear model. MR imaging findings included lateral and/or posterior rectocele, rectal prolapse, intussusception, ballooning of levator hiatus with impingement of pelvic organs and dyskinetic puborectalis muscle.

RESULTS

There were 21 males with ODS due to anismus (Group 1) and 15 with ODS due to rectal prolapse/intussusception (Group 2). Mean age of the entire group was 53.6 ± 4.1 years (range 18-77 years). Patients in Group 1 were slightly older than those in Group 2 (age peak, sixth decade in 47.6 vs 20.0%, p < 0.05). Symptoms most frequently associated with Group 1 patients included small volume and hard feces (85.0%, p < 0.01), excessive strain at stool (81.0%, p < 0.05), tenesmus and fecaloma formation (57.1 and 42.9%, p < 0.05); symptoms most frequently associated with Group 2 patients included mucous discharge, rectal bleeding and pain (86.7%, p < 0.05), prolonged toilet time (73.3%, p < 0.05), fragmented evacuation with or without digitation (66.7%, p < 0.005). Voiding outflow obstruction was more frequent in Group 1 (19.0 vs 13.3%; p < 0.05), while non-bacterial prostatitis and sexual dysfunction prevailed in Group 2 (26.7 and 46.7%, p < 0.05). At MR defecography, two major categories of findings were detected: a dyskinetic pattern (Type 1), seen in all Group 1 patients, which was characterized by non-relaxing puborectalis muscle, sand-glass configuration of the anorectum, poor emptying rate, limited pelvic floor descent and final residue ≥ 2/3; and a prolapsing pattern (Type 2), seen in all Group 2 patients, which was characterized by rectal prolapse/intussusception, ballooning of the levator hiatus with impingement of the rectal floor and prostatic base, excessive pelvic floor descent and residue ≤ 1/2. Posterolateral outpouching defined as perineal hernia was present in 28.6% of patients in Group 1 and were absent in Group 2. The average levator plate angle on straining differed significantly in the two patterns (21.3° ± 4.1 in Group 1 vs 65.6° ± 8.1 in Group 2; p < 0.05). Responses to the phone interview were obtained from 31 patients (18 of Group 1 and 13 of Group 2, response rate, 86.1%). Patients of Group 1 were always treated without surgery (i.e., biofeedback, dietary regimen, laxatives and/or enemas) which resulted in symptomatic improvement in 12/18 cases (66.6%). Of the patients in Group 2, 2/13 (15.3) underwent surgical repair, consisting of stapled transanal rectal resection (STARR) which resulted in symptom recurrence after 6 months and laparoscopic ventral rectopexy which resulted in symptom improvement. The other 11 patients of Group 2 were treated without surgery with symptoms improvement in 3 (27.3%).

CONCLUSIONS

The appearance of various abnormalities at MR defecography in men with ODS shows 2 distinct patterns which may have potential relevance for treatment planning, whether conservative or surgical.

A biomechanical model of the human defecatory system to investigate mechanisms of continence

This article presents a method to fabricate, measure and control a physical simulation of the human defecatory system to investigate individual and combined effects of anorectal angle and sphincter pressure on continence. To illustrate the capabilities and clinical relevance of the work, the influence of a passive-assistive artificial anal sphincter (FENIX^TM) is evaluated. A model rectum and associated soft tissues, based on geometry from an anonymised computed tomography dataset, was fabricated from silicone and showed behavioural realism to the biological system and ex vivo tissue. Simulated stool matter with similar rheological properties to human faeces was developed. Instrumentation and control hardware were used to regulate injection of simulated stool into the system, automate balloon catheter movement through the anal canal, define the anorectal angle and monitor stool flow rate, intra-rectal pressure, anal canal pressure and puborectalis force. Studies were conducted to examine the response of anorectal angles at 80°, 90° and 100° with simulated stool. Tests were then repeated with the inclusion of a FENIX device. Stool leakage was reduced as the anorectal angle became more acute. Conversely, intra-rectal pressure increased. Overall inclusion of the FENIX reduced faecal leakage, while combined effects of the FENIX and an acute anorectal angle showed the greatest resistance to faecal leakage. These data demonstrate that the anorectal angle and sphincter pressure are fundamental in maintaining continence. Furthermore, it demonstrates that use of the FENIX can increase resistance to faecal leakage and reduce anorectal angles required to maintain continence. Physical simulation of the defecatory system is an insightful tool to better understand, in a quantitative manner, the effects of the anorectal angle and sphincter pressure on continence. This work is valuable in helping improve our understanding of the physical behaviour of the continence mechanism and facilitating improved technologies to treat severe faecal incontinence.

MR-FLIP: a new method that combines a functional lumen imaging probe with anatomical information for spatial compliance assessment of the anal sphincter muscles

AIM

Continence results from a complex interplay between anal canal (AC) muscles and sensorimotor feedback mechanisms. The passive ability of the AC to withstand opening pressure - its compliance - has recently been shown to correlate with continence. A functional lumen imaging probe (FLIP) is used to assess AC compliance, although it provides no anatomical information. Therefore, assessment of the compliance specific anatomical structures has not been possible, and the anatomical position of critical functional zones remains unknown. In addition, the FLIP technique assumes a circular orifice cross-section, which has not been shown for the AC. To address these shortcomings, a technique combining FLIP with a medical imaging modality is needed.

METHOD

We implemented a new research method (MR-FLIP) that combines FLIP with MR imaging. Twenty healthy volunteers underwent MR-FLIP and conventional FLIP assessment. MR-FLIP was validated by comparison with FLIP results. Anatomical markers were identified, and the cross-sectional shape of the orifice was investigated.

RESULTS

MR-FLIP provides compliance measurements identical to those obtained by conventional FLIP. Anatomical analysis revealed that the least compliant AC zone was located at the proximal end of the external anal sphincter (EAS). The cross-sectional shape of the AC was found to deviate only slightly from circularity in healthy volunteers.

CONCLUSION

The proposed method is equivalent to classical FLIP. It establishes for the first time direct mapping between local tissue compliance and anatomical structure, which is key to gaining novel insights into (in)continence. In addition, MR-FLIP provides a tool for better understanding conventional FLIP measurements in the AC by quantifying its limitations and assumptions.

Sonographic appearance of anal cushions of hemorrhoids

AIM

To evaluate the diagnostic value of different sonographic methods in hemorrhoids.

METHODS

Forty-two healthy volunteers and sixty-two patients with grades I-IV hemorrhoids received two different sonographic examinations from January 2013 to January 2016 at the First and Second Hospitals of Xinjiang Medical University in a prospective way. We analyzed the ultrasonographic findings of these participants and evaluated the outcomes. Resected grades III and IV hemorrhoid tissues were pathologically examined. The concordance of ultrasonographic results with pathology results was assessed with the Cohen’s kappa coefficient.

RESULTS

All healthy volunteers and all patients had no particular complications related to sonography. There were no statistically significant differences between the participants regarding age (P = 0.5919), gender (P = 0.4183), and persistent symptoms (P > 0.8692). All healthy control participants had no special findings. However, 30 patients with hemorrhoids showed blood signals around the dentate line on ultrasonography. When grades I and II hemorrhoids were analyzed, there were no significant differences between transrectal ultrasound (TRUS), transperianal ultrasound (TPUS), and transvaginal ultrasound (TVUS) (P > 0.05). Grades III and IV hemorrhoids revealed blood flow with different directions which could be observed as a “mosaic pattern”. In patients with grades III and IV hemorrhoids, the number of patients with “mosaic pattern” as revealed by TRUS, TPUS and TVUS was 22, 12, and 4, respectively. Patients with grades III and IV disease presented with a pathologically abnormal cushion which usually appeared as a “mosaic pattern” in TPUS and an arteriovenous fistula in pathology. Subepithelial vessels of resected grades III and IV hemorrhoid tissues were manifested by obvious structural impairment and retrograde and ruptured changes of internal elastic lamina. Some parts of the Trietz’s muscle showed hypertrophy and distortion. Arteriovenous fistulas and venous dilatation were obvious in the anal cushion of hemorhoidal tissues. After pathological results with arteriovenous fistulas were taken as the standard reference, we evaluated the compatibility between the two methods according to the Cohen’s kappa co-efficiency calculation. The compatibility (Cohein kappa co-efficiency value) between “mosaic pattern” in the TPUS and arteriovenous fistula in pathology was very good (ĸ = 0.8939). When compared between different groups, TRUS presented the advantage that the mosaic pattern could be confirmed in more patients, especially for group A. There was a statistical difference when comparing group A with group B or C (P < 0.05 for both). There were obvious statistical differences between group A and group B with regard to the vessel diameter and blood flow velocity measured by TRUS (P < 0.05).

CONCLUSION

Patients with grades III and IV hemorrhoids present with a pathologically abnormal cushion which usually appears as a “mosaic pattern” in sonography, which is in accord with an arteriovenous fistula in pathology. There are clearly different hemorrhoid structures shown by sonography. “Mosaic pattern” may be a parameter for surgical indication of grades III and IV hemorrhoids.

Proposed definition of the vaginal cuff and paracolpium clinical target volume in postoperative uterine cervical cancer

PURPOSE

The aim of this study was to develop an appropriate definition for vaginal cuff and paracolpium clinical target volume (CTV) for postoperative intensity modulated radiation therapy in patients with uterine cervical cancer.

METHODS AND MATERIALS

A working subgroup was organized within the Radiation Therapy Study Group of the Japan Clinical Oncology Group to develop a definition for the postoperative vaginal cuff and paracolpium CTV in December 2013. The group consisted of 5 radiation oncologists who specialized in gynecologic oncology and a gynecologic oncologist. A comprehensive literature review that included anatomy, surgery, and imaging fields was performed and was followed by multiple discreet face-to-face discussions and e-mail messages before a final consensus was reached.

RESULTS

Definitions for the landmark structures in all directions that demarcate the vaginal cuff and paracolpium CTV were decided by consensus agreement of the working group. A table was created that showed boundary structures of the vaginal cuff and paracolpium CTV in each direction.

CONCLUSIONS

A definition of the postoperative cervical cancer vaginal cuff and paracolpium CTV was developed. It is expected that this definition guideline will serve as a template for future radiation therapy clinical trial protocols, especially protocols involving intensity modulated radiation therapy.

Artificial Muscle Devices: Innovations and Prospects for Fecal Incontinence Treatment

Fecal incontinence describes the involuntary loss of bowel content, which is responsible for stigmatization and social exclusion. It affects about 45% of retirement home residents and overall more than 12% of the adult population. Severe fecal incontinence can be treated by the implantation of an artificial sphincter. Currently available implants, however, are not part of everyday surgery due to long-term re-operation rates of 95% and definitive explantation rates of 40%. Such figures suggest that the implants fail to reproduce the capabilities of the natural sphincter. This article reviews the artificial sphincters on the market and under development, presents their physical principles of operation and critically analyzes their performance. We highlight the geometrical and mechanical parameters crucial for the design of an artificial fecal sphincter and propose more advanced mechanisms of action for a biomimetic device with sensory feedback. Dielectric electro-active polymer actuators are especially attractive because of their versatility, response time, reaction forces, and energy consumption. The availability of such technology will enable fast pressure adaption comparable to the natural feedback mechanism, so that tissue atrophy and erosion can be avoided while maintaining continence during daily activities.

Magnetic resonance imaging of pelvic floor disorders

Physical examination alone is often inadequate for evaluation of pelvic floor dysfunction. Magnetic resonance imaging (MRI) is a robust modality that can provide high-quality anatomic and functional evaluation of the pelvic floor. Although lack of standardized technique and radiologist inexperience may be relative deterrents in universal acceptance of pelvic floor MRI, the role of MRI is increasing as it is technically feasible on most magnets and offers some advantages over the traditional fluoroscopic defecography. This review focuses on the technical and interpretational aspects of anatomic and functional pelvic floor MRI.

Comparison between dynamic cystocolpoproctography and dynamic pelvic floor MRI: pros and cons: which is the "functional" examination for anorectal and pelvic floor dysfunction?

"Functional" imaging of anorectal and pelvic floor dysfunction has assumed an important role in the diagnosis and management of these disorders. Although defecography has been widely practiced for decades to evaluate the dynamics of rectal emptying, debate concerning its clinical relevance, how it should be done and interpreted continues. Due to the recognition of the association of defecatory disorders with pelvic organ prolapse in women, the need to evaluate the pelvic floor as a unit has arisen. To meet this need, defecography has been extended to include not only evaluation of defecation disorders but also the rest of the pelvic floor by opacifying the small bowel, vagina, and the urinary bladder. The term "dynamic cystocolpoproctography" (DCP) has been appropriately applied to this examination. Rectal emptying performed with DCP provides the maximum stress to the pelvic floor resulting in complete levator ani relaxation. In addition to diagnosing defecatory disorders, this method of examination demonstrates maximum pelvic organ descent and provides organ-specific quantification of organ prolapse, information that is only inferred by means of physical examination. It has been found to be of clinical value in patients with defecation disorders and the diagnosis of associated prolapse in other compartments that are frequently unrecognized by history taking and the limitations of physical examination. Pelvic floor anatomy is complex and DCP does not show the anatomical details pelvic magnetic resonance imaging (MRI) provides. Technical advances allowing acquisition of dynamic rapid MRI sequences has been applied to pelvic floor imaging. Early reports have shown that pelvic MRI may be a useful tool in pre-operative planning of these disorders and may lead to a change in surgical therapy. Predictions of hypothetical increase cancer incidence and deaths in patients exposed to radiation, the emergence of pelvic floor MRI in addition to questions relating to the clinical significance of DCP findings have added to these controversies. This review analyses the pros and cons between DCP and dynamic pelvic floor MRI, addresses imaging and interpretive controversies, and their relevance to clinical management.

MRI role in morphological and functional assessment of the levator ani muscle: use in patients affected by stress urinary incontinence (SUI) before and after pelvic floor rehabilitation

OBJECTIVE

Pelvic floor dysfunctions affect a very high proportion of female population. Magnetic resonance imaging is the only technique able to provide a multiplanar overview of pelvic organs and muscles without the use of ionizing radiation. The aim of our prospective study is to objectively evaluate the effectiveness of perineal re-education applying MR technique.

MATERIALS AND METHODS

22 patients affected by stress urinary incontinence were enrolled in our prospective study. They underwent urogynaecological, urodynamic examinations, and a questionnaire about symptoms (ICIQ-UI) to investigate the degree of their interference with daily activities. Then they underwent a morphological and dynamic MR exam.

RESULTS

The pre-perineal rehabilitation MR examinations showed an asymmetry of the levator ani muscle in 87% of patients; the remaining 13% showed a muscular bilateral volume reduction. In the group with unilateral defect, the muscle total volume had values between 15 and 21 cm3. Its overall volume was 34.2% smaller on the defective side (9.28±0.26 cm3) compared to the normal side (12.64±12.31 cm3, P<0.001). In patients with a bilateral impairment, the muscle was replaced by fibro-fatty tissue, without a significant asymmetry between the two sides. The post-perineal rehabilitation MR tests showed three different degrees of response to therapy, with a "complete response" found in 67% of patients and no response in 13%.

CONCLUSIONS

MR is an useful tool in the management of patients affected by stress urinary incontinence with indication for perineal rehabilitation. Its objective data allow to distinguish different types of response to therapy and, consequently, different outcomes in terms of additional treatments.

MR imaging of the pelvic floor: defecography

Defecography by magnetic resonance (MR) imaging makes it possible to view the multiple compartments of the pelvic floor at one examination, with high-resolution images at rest and dynamic images, providing accurate evaluation of the morphology and function of the anorectal and pelvic organs and muscles, involved in pelvic floor dynamics. MR imaging of the pelvic floor identifies the diseases affecting the evacuation mechanism, providing information essential for surgical planning and choice of treatment approach. This article focuses on the MR details of the pelvic floor anatomy and the most commonly observed anatomic and functional abnormalities.

Anorectal physiology and testing

A good understanding of anorectal physiology is essential for the diagnosis and appropriate treatment of various anorectal disorders, such as fecal incontinence, constipation, and pain. This article reviews the physiology of the anorectum and details the various investigations used to diagnose anorectal physiology disorders. These anatomic and functional tests include anal manometry, endoanal ultrasound, defecography, balloon expulsion test, magnetic resonance imaging, pudendal nerve terminal motor latency, electromyography, and colonic transit studies. Indications for investigations, steps in performing the tests, and interpretation of results are discussed.

Does conventional defecography has a role to play in evaluation of evacuatory disorders in Indian population?

Barium studies are one of the best investigations for evaluating submucosal and extrinsic mass lesions. However, barium studies bring less money, are operator dependent and one of the more difficult investigations for radiologists to master. Economic factors have acted as powerful disincentives for performing gastrointestinal (GI) fluoroscopy in most radiology practices. In this pictorial essay, we discuss the role of conventional defecography in evaluating evacuatory disorders in the Indian population.

MR-defecography in obstructed defecation syndrome (ODS): technique, diagnostic criteria and grading

BACKGROUND

The aim of this study was to evaluate the use of a magnetic resonance (MR)-based classification system of obstructive defecation syndrome (ODS) to guide physicians in patient management.

METHODS

The medical records and imaging series of 105 consecutive patients (90 female, 15 male, aged 21-78 years, mean age 46.1 ± 5.1 years) referred to our center between April 2011 and January 2012 for symptoms of ODS were retrospectively examined. After history taking and a complete clinical examination, patients underwent MR imaging according to a standard protocol using a 0.35 T permanent field, horizontally oriented open-configuration magnet. Static and dynamic MR-defecography was performed using recognized parameters and well-established diagnostic criteria.

RESULTS

Sixty-seven out of 105 (64 %) patients found the prone position more comfortable for the evacuation of rectal contrast while 10/105 (9.5 %) were unable to empty their rectum despite repeated attempts. Increased hiatus size, anterior rectocele and focal or extensive defects of the levator ani muscle were the most frequent abnormalities (67.6, 60.0 and 51.4 %, respectively). An MR-based classification was developed based on the combinations of abnormalities found: Grade 1 = functional abnormality, including paradoxical contraction of the puborectalis muscle, without anatomical defect affecting the musculo-fascial structures; Grade 2 = functional defect associated with a minor anatomical defect such as rectocele ≤ 2 cm in size and/or first-degree intussusception; Grade 3 = severe defects confined to the posterior anatomical compartment, including >2 cm rectocele, second- or higher-degree intussusception, full-thickness external rectal prolapse, poor mesorectal posterior fixation, rectal descent >5 cm, levator ani muscle rupture, ballooning of the levator hiatus and focal detachment of the endopelvic fascia; Grade 4 = combined defects of two or three pelvic floor compartments, including cystocele, hysterocele, enlarged urogenital hiatus, fascial tears enterocele or peritoneocele; Grade 5 = changes after failed surgical repair abscess/sinus tracts, rectal pockets, anastomotic strictures, small uncompliant rectum, kinking and/or lateral shift of supra-anastomotic portion and pudendal nerve entrapment.

CONCLUSIONS

According to our classification, Grades 1 and 2 may be amenable to conservative therapy; Grade 3 may require surgical intervention by a coloproctologist; Grade 4 would need a combined urogynecological and coloproctological approach; and Grade 5 may require an even more complex multidisciplinary approach. Validation studies are needed to assess whether this MR-based classification system leads to a better management of patients with ODS.

Assessment of levator ani morphology and function in asymptomatic nulliparous women via static and dynamic magnetic resonance imaging

OBJECTIVE

To evaluate levator ani morphology and function in healthy nulliparous women using static and dynamic magnetic resonance imaging.

METHODS

Eighty asymptomatic, healthy nulliparous Chinese women (mean age, 25.3±3.5years) volunteered for the present study. Static T2-weighted fast spin-echo images were employed to evaluate levator ani morphology; dynamic T2-weighted fast imaging employing steady-state acquisition was used to evaluate its function. A 2 samples t test was employed to compare groups.

RESULTS

No morphologic abnormality was detected in the 80 healthy nulliparous women. However, 15% (12/80) of women had various degrees of pelvic organ descent below the pubococcygeal line. In these women, the width of the pubic portion of the levator ani was significantly reduced during straining, whereas the levator plate angle, the levator hiatus area, and the H and M line lengths were enlarged. These changes were associated with weakened levator ani function and pelvic floor laxity.

CONCLUSION

Functional abnormality of the levator ani muscle was noted in nulliparous women at static and dynamic magnetic resonance imaging. Further follow-up investigation is needed to confirm whether women with functional abnormality are more likely to develop a prolapse after vaginal birth.

Diffusion tensor imaging and fiber tractography for the visualization of the female pelvic floor

In the past decade, the evaluation of the pelvic support for understanding pelvic floor dysfunction by means of magnetic resonance imaging (MRI) has been an emerging area of research. Both static and dynamic MRI techniques have been effectively applied as a diagnostic resource to reveal abnormalities to the muscular pelvic support, but fail to unravel the precise pathophysiology of this complex disorder. Diffusion tensor imaging (DTI) and tractography comprise enhanced MRI techniques that enable the three-dimensional visualization of anisotropic tissue, such as muscle fibers, and provide a quantitative description of tissue organization and integrity. Quantifying DTI and fiber tractography might be able to reveal microstructural abnormalities in the pelvic support that are not noticeable using conventional MRI techniques. In this article, we discuss relevant anatomy, the current state of DTI and tractography in the evaluation of the female pelvic floor, and their potential future clinical applications.

MRI in evaluation of perianal fistula

This essay illustrates the usefulness of MRI in evaluating perianal fistulas, a common disease, notorious for recurrence if not assessed and treated adequately. MRI exquisitely depicts the perianal anatomy and shows the fistulous tracks and their associated ramifications and abscesses. It thus provides an excellent preoperative understanding of the disease, enabling selection of the most appropriate surgical treatment and therefore minimising all chances of recurrence.

Four-dimensional sonographic evaluation of avulsion of the levator ani according to delivery mode

OBJECTIVE

To determine the frequency of avulsion of the levator ani muscle in primiparous women according to delivery mode, using introital four-dimensional ultrasonography.

METHODS

We performed a prospective observational study at a tertiary obstetric unit. One hundred and eighty primiparous women were included and divided into three groups: normal vaginal delivery without episiotomy, forceps delivery and Cesarean section groups. Between 40 and 120 days after delivery, four-dimensional ultrasonography was performed in order to evaluate the integrity of the levator ani muscle. The operator was blinded to all clinical data and was not aware of delivery mode. The influence of other variables associated with delivery such as birth weight, body mass index, maternal age and use of epidural anesthesia was also studied.

RESULTS

Avulsion of the puborectalis component of the levator ani muscle was detected on ultrasonography in 61.7% of women who had undergone a forceps delivery, compared with 13.3% of those who had had a normal vaginal delivery and 0% of those who had had a Cesarean section. Bilateral avulsion was observed in 12/60 (20.0%) of the forceps group and in 2/60 (3.3%) of the normal vaginal delivery group (P < 0.001). Other variables did not seem to influence prevalence.

CONCLUSIONS

Forceps delivery is associated with an increased rate of avulsion of the puborectalis component of the levator ani muscle. The effect of forceps use is independent of other delivery-related variables.

Diffusion tensor imaging of the anal canal at 3 tesla: feasibility and reproducibility of anisotropy measures

PURPOSE

To assess the feasibility and reproducibility of 3-tesla diffusion tensor imaging (DTI) of the anal canal.

MATERIALS AND METHODS

DTI was performed in 25 men with no clinical history of anal canal disease undergoing MRI for prostate cancer. Analysis of fractional anisotropy (FA), relative anisotropy (RA), and apparent diffusion coefficient (ADC) were determined for the epithelial/subepithelial layer, internal sphincter, external sphincter, and puborectalis. The directionality of diffusion was recorded from color-coded tractography maps. Obturator internus and gluteus maximus served as reference muscles. Mean (SD) of values for FA, RA, and ADC were compared using analysis of variance. Intra and inter-rater agreement and test reproducibility (n = 5) was assessed by Bland-Altman statistics.

RESULTS

Mean (SD) for the epithelial/subepithelial layer, internal, external sphincter, and puborectalis were as follows: FA: 0.283 (0.099); 0.337 (0.049); 0.415 (0.072); and 0.407 (0.062), respectively. RA: 0.241 (0.094); 0.292 (0.050); 0.371 (0.083); 0.361 (0.067), respectively; and ADC: 1.49 (0.23); 1.59 (0.19); 1.51 (0.28); and 1.54 (0.29) × 10(-3) mm(2) /s, respectively. Good overall intra and inter-rater agreement and test-retest reproducibility was noted (coefficient of variation of 4.8-19.4% and 5.9-12.9%, respectively).

CONCLUSION

Anisotropy is evident in the anal canal with good inter-rater agreement and test reproducibility.

Endoanorectal ultrasonography

Endoanorectal ultrasonography (EARUS) may be used for diagnosing various anorectal disorders. EARUS is easy to perform, has a short learning curve, and causes less discomfort than routine digital examination. Anal sphincters can be clearly visualized, and one can easily distinguish between the internal (hypoechoic) and external (hyperechoic) anal sphincters. Other pelvic floor structures, like the puborectalis muscle, can also be visualized. The use of contrast agents can increase the accuracy of EARUS in the assessment of perianal fistulae. In addition, EARUS is an excellent alternative to expensive magnetic resonance imaging. Besides its use in incontinence and perianal sepsis, the presence of slight or massive submucosal invasion in early rectal cancer may be imaged in greater detail. With 3-dimensional EARUS, it is possible to diagnose the anorectal diseases, in multiplane, with high spatial resolution, adding important information about the therapeutic decision. The normal sonographic anatomy of the anorectum, sonographic findings of anorectal diseases, and indications and limitations of endosonography with complementary techniques such as transvaginal and transperineal ultrasound are reviewed in this article.

Malignant tumors of the female pelvic floor: self-assessment module

The educational objectives for this self-assessment module are for the participant to exercise, self-assess, and improve his or her understanding of malignant tumors of the female pelvic floor and the imaging features that determine therapy.