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.

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.

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.

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.

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.

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.

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.

This article represents part 3 of the EFSUMB Recommendations and Guidelines for Gastrointestinal Ultrasound (GIUS). It provides an overview of the examination techniques recommended by experts in the field of endorectal/endoanal ultrasound (ERUS/EAUS), as well as perineal ultrasound (PNUS). The most important indications are rectal tumors and inflammatory diseases like fistula and abscesses in patients with or without inflammatory bowel disease (IBD). PNUS sometimes is more flexible and convenient compared to ERUS. However, the technique of ERUS is quite well established, especially for the staging of rectal cancer. EAUS also gained ground in the evaluation of perianal diseases like fistulas, abscesses and incontinence. For the staging of perirectal tumors, the use of PNUS in addition to conventional ERUS could be recommended. For the staging of anal carcinomas, PNUS can be a good option because of the higher resolution. Both ERUS and PNUS are considered excellent guidance methods for invasive interventions, such as the drainage of fluids or targeted biopsy of tissue lesions. For abscess detection and evaluation, contrast-enhanced ultrasound (CEUS) also helps in therapy planning.

To establish the diagnostic test accuracy of two-dimensional (2D) and four-dimensional (4D) transperineal ultrasound (TPUS) for diagnosis of posterior pelvic floor disorders in women with obstructed defecation syndrome (ODS), in order to assess if 4D ultrasound imaging provides additional value.

This was a prospective cohort study of 121 consecutive women with ODS. Symptoms of ODS and pelvic organ prolapse on clinical examination were assessed using validated methods. All women underwent both 2D- and 4D-TPUS. Imaging analysis was performed by two blinded observers. Posterior pelvic floor disorders were dichotomized into presence or absence, according to predefined cut-off values. In the absence of a reference standard, a composite reference standard was created from a combination of results of evacuation proctography, magnetic resonance imaging and endovaginal ultrasound. Primary outcome measures were diagnostic test characteristics of 2D- and 4D-TPUS for rectocele, enterocele, intussusception and anismus. Secondary outcome measures were interobserver agreement, agreement between the two imaging techniques, and association of severity of ODS symptoms and degree of posterior vaginal wall prolapse with conditions observed on imaging.

For diagnosis of all four posterior pelvic floor disorders, there was no difference in sensitivity or specificity between 2D- and 4D-TPUS (P = 0.131-1.000). Good agreement between 2D- and 4D-TPUS was found for diagnosis of rectocele (κ = 0.675) and moderate agreement for diagnoses of enterocele, intussusception and anismus (κ = 0.465-0.545). There was no difference in rectocele depth measurements between the techniques (19.9 mm for 2D vs 19.0 mm for 4D, P = 0.802). Interobserver agreement was comparable for both techniques, although 2D-TPUS had excellent interobserver agreement for diagnosis of enterocele and rectocele depth measurements, while this was only moderate and good, respectively, for 4D-TPUS. Diagnoses of rectocele and enterocele on both 2D- and 4D-TPUS were significantly associated with degree of posterior vaginal wall prolapse on clinical examination (odds ratio (OR) = 1.89-2.72). The conditions observed using either imaging technique were not associated with severity of ODS symptoms (OR = 0.82-1.13).

There is no evidence of superiority of 4D ultrasound acquisition to dynamic 2D ultrasound acquisition for the diagnosis of posterior pelvic floor disorders. 2D- and 4D-TPUS could be used interchangeably to screen women with symptoms of ODS. Copyright © 2018 ISUOG. Published by John Wiley & Sons Ltd.

To establish the diagnostic test accuracy of evacuation proctography, magnetic resonance imaging (MRI), transperineal ultrasonography, and endovaginal ultrasonography for detecting posterior pelvic floor disorders (rectocele, enterocele, intussusception, and anismus) in women with obstructed defecation syndrome and secondarily to identify the most patient-friendly imaging technique.

In this prospective cohort study, 131 women with symptoms of obstructed defecation syndrome underwent evacuation proctogram, MRI, and transperineal and endovaginal ultrasonography. Images were analyzed by two blinded observers. In the absence of a reference standard, latent class analysis was used to assess diagnostic test accuracy of multiple tests with area under the curve (AUC) as the primary outcome measure. Secondary outcome measures were interobserver agreement calculated as Cohen's κ and patient acceptability using a visual analog scale.

No significant differences in diagnostic accuracy were found among the imaging techniques for all the target conditions. Estimates of diagnostic test accuracy were highest for rectocele using MRI (AUC 0.79) or transperineal ultrasonography (AUC 0.85), for enterocele using transperineal (AUC 0.73) or endovaginal ultrasonography (AUC 0.87), for intussusception using evacuation proctography (AUC 0.76) or endovaginal ultrasonography (AUC 0.77), and for anismus using endovaginal (AUC 0.95) or transperineal ultrasonography (AUC 0.78). Interobserver agreement for the diagnosis of rectocele (κ 0.53-0.72), enterocele (κ 0.54-0.94) and anismus (κ 0.43-0.81) was moderate to excellent, but poor to fair for intussusception (κ -0.03 to 0.37) with all techniques. Patient acceptability was better for transperineal and endovaginal ultrasonography as compared with MRI and evacuation proctography (P<.001).

Evacuation proctography, MRI, and transperineal and endovaginal ultrasonography were shown to have similar diagnostic test accuracy. Evacuation proctography is not the best available imaging technique. There is no one optimal test for the diagnosis of all posterior pelvic floor disorders. Because transperineal and endovaginal ultrasonography have good test accuracy and patient acceptability, we suggest these could be used for initial assessment of obstructed defecation syndrome.

ClinicalTrials.gov, NCT02239302.

In recent years, a large number of studies have been published on the clinical relevance of pelvic floor three-dimensional (3D) transperineal ultrasound. Several studies compare sonography with other imaging modalities or clinical examination. The quality of reporting in these studies is not known. The objective of this systematic review was to determine the compliance of diagnostic accuracy studies investigating pelvic floor 3D ultrasound with the Standards for Reporting of Diagnostic Accuracy (STARD) guidelines.

Published articles on pelvic floor 3D ultrasound were identified by a systematic literature search of MEDLINE, Web of Science and Scopus databases. Prospective and retrospective studies that compared pelvic floor 3D ultrasound with other clinical and imaging diagnostics were included in the analysis. STARD compliance was assessed and quantified by two independent investigators, using 22 of the original 25 STARD checklist items. Items with the qualifier 'if done' (Items 13, 23 and 24) were excluded because they were not applicable to all papers. Each item was scored as reported (score = 1) or not reported (score = 0). Observer variability, the total number of reported STARD items per article and summary scores for each item were calculated. The difference in total score between STARD-adopting and non-adopting journals was tested statistically, as was the effect of year of publication.

Forty studies published in 13 scientific journals were included in the analysis. Mean ± SD STARD checklist score of the included articles was 16.0 ± 2.5 out of a maximum of 22 points. The lowest scores (< 50%) were found for reporting of handling of indeterminate results or missing responses, adverse events and the time interval between tests. Interobserver agreement for rating the STARD items was excellent (intraclass correlation coefficient, 0.77). An independent t-test showed no significant mean difference ± SD in total STARD checklist score between STARD-adopting and non-adopting journals (16.4 ± 2.2 vs 15.9 ± 2.6, respectively). Mean ± SD STARD checklist score for articles published in 2003-2009 was lower, but not statistically different, compared with those published in 2010-2015 (15.2 ± 2.5 vs 16.6 ± 2.4, respectively).

The overall compliance with reporting guidelines of diagnostic accuracy studies on pelvic floor 3D transperineal ultrasound is relatively good compared with other fields of medicine. However, specific checklist items require more attention when reported. Copyright © 2016 ISUOG. Published by John Wiley & Sons Ltd.

Transperineal ultrasound is an inexpensive, safe and painless technique that dynamically and non-invasively evaluates the anorectal area. It has multiple indications, mainly in urology, gynaecology, surgery and gastroenterology, with increased use in the last decade. It is performed with conventional probes, positioned directly above the anus, and may capture images of the anal canal, rectum, puborectalis muscle (posterior compartment), vagina, uterus, (central compartment), urethra and urinary bladder (anterior compartment). Evacuatory disorders and pelvic floor dysfunction, like rectoceles, enteroceles, rectoanal intussusception, pelvic floor dyssynergy can be diagnosed using this technique. It makes a dynamic evaluation of the interaction between pelvic viscera and pelvic floor musculature, with images obtained at rest, straining and sustained squeezing. This technique is an accurate examination for detecting, classifying and following of perianal inflammatory disease. It can also be used to sonographically guide drainage of deep pelvic abscesses, mainly in patients who cannot undergo conventional drainage. Transperineal ultrasound correctly evaluates sphincters in patients with fecal incontinence, postpartum and also following surgical repair of obstetric tears. There are also some studies referring to its role in anal stenosis, for the measurement of the anal cushions in haemorrhoids and in chronic anal pain.