Anal fistula: Levovist-enhanced endoanal ultrasound: a pilot study

The Use of Endoscopic Ultrasonography in Inflammatory Bowel Disease: A Review of the Literature

The diagnosis of inflammatory bowel disease (IBD) can sometimes be challenging. By corroborating clinical, imaging and histological data, the two main entities of IBD, ulcerative colitis and Crohn's disease (CD), can be differentiated in most cases. However, there remains 10-20% of patients where the diagnosis cannot be accurately established, in which case the term "IBD unclassified" is used. The imaging techniques most used to evaluate patients with IBD include colonoscopy, ultrasonography and magnetic resonance imaging. Endoscopic ultrasonography is mainly recommended for the evaluation of perianal CD. Through this work, we aim to identify other uses of this method in the case of patients with IBD.

Perianal fistulas: A review with emphasis on preoperative imaging

PURPOSE

We aim to present a comprehensive literature review which focuses on the preoperative imaging of perianal fistulas.

MATERIAL/METHODS

Pelvic magnetic resonance imaging (MRI) and endoanal ultrasound (EAUS) are the two first-line imaging modalities for the preoperative evaluation of patients with perianal fistulas. We conducted a search in PubMed, Scopus and Google Scholar concerning articles comparing pelvic MRI with EAUS, which were published from 1994 until 2019.

RESULTS

In most articles, pelvic MRI is superior to EAUS for the evaluation of perianal fistulas (especially for supralevator and extrasphincteric ones). Preoperative pelvic MRI is associated with statistically significant better results and prognosis after surgical treatment of the disease. Preoperative EAUS poses high sensitivity and specificity in identifying intersphincteric and transsphincteric perianal fistulas, as well as the internal opening of a fistula-in-ano. There is only one meta-analysis which compares the diagnostic accuracy of the two mentioned imaging modalities in preoperative fistula detection. Sensitivity of both - pelvic MRI and EAUS, is acceptably high (0.87). Specificity of pelvic MRI is 0.69 in comparison to EAUS (0.43), but both values are considered low.

CONCLUSIONS

Future well-designed prospective studies are needed to investigate the diagnostic accuracy of pelvic MRI and EAUS in the preoperative assessment of patients with perianal fistulas. Moreover, the combination of pelvic MRI and EAUS should also be studied, since several published articles suggest that it could lead to improved diagnostic accuracy. A novel treatment algorithm for perianal fistulas could arise from this study.

Intra-Cavitary Contrast-Enhanced Ultrasound: A Novel Radiation-Free Method for Detecting Abscess-Associated Penetrating Disease in Crohn's Disease

BACKGROUND AND AIM

Penetrating disease is a common condition complicating Crohn's disease [CD]. Establishing the presence of a fistula and the anatomical definition of the fistulous tracts are essential for deciding on appropriate treatment strategies. We aimed to assess the diagnostic accuracy of intra-cavitary contrast-enhanced ultrasound [IC-CEUS] for the detection of a fistulous tract associated with abscesses in CD patients.

METHODS

In this prospective cohort study, consecutive CD patients suspected of having an intra-abdominal abscess, who were referred for US-guided aspiration were recruited. IC-CEUS was performed by injecting diluted contrast agent [SonoVue] into the abscess cavity immediately following the ultrasound-guided needle abscess aspiration and drainage. The diagnostic accuracy of IC-CEUS in demonstrating the presence of fistulous tracts was compared with that of computed tomography enterography/magnetic resonance enterography [CTE/MRE], using surgical and gross pathological findings as the reference standard.

RESULTS

Thirty-one patients who underwent IC-CEUS and subsequent surgery were included in the final analysis. IC-CEUS demonstrated fistulous/sinus tracts in 26 of 31 participants with a sensitivity and specificity of 86.7 % (95% confidence interval [CI], 68.4-95.6%) and 100% [95% CI, 5.5-100.0%], respectively. Moreover, IC-CEUS correctly demonstrated fistulous/sinus tracts in 13 participants without delineation of fistulous/sinus tracts on CTE/MRE. Combining IC-CEUS and CTE/MRE, the fistula/sinus tract was clearly demonstrated in 29 patients [93.5%, 29/31]. The mean duration of the IC-CEUS procedure was 8.6 min [range 5.0-12.0]. No severe adverse events occurred during the IC-CEUS procedure.

CONCLUSION

In this pilot study, IC-CEUS accurately delineated the anatomical definition of fistulous/sinus tracts associated with intra-abdominal abscesses in CD patients. As a radiation-free and safe technique, IC-CEUS may be used as an alternative/adjunctive method to CTE/MRE for detecting penetrating disease in patients with CD.

The treatment of anal fistula: second ACPGBI Position Statement - 2018

It is over 10 years since the first ACPGBI Position Statement on the management of anal fistula was published in 2007. This second edition is the result of scrutiny of the literature published during this time; it updates the original Position Statement and reviews the published evidence surrounding treatments for anal fistula that have been developed since the original publication.

How to perform Contrast-Enhanced Ultrasound (CEUS)

"How to perform contrast-enhanced ultrasound (CEUS)" provides general advice on the use of ultrasound contrast agents (UCAs) for clinical decision-making and reviews technical parameters for optimal CEUS performance. CEUS techniques vary between centers, therefore, experts from EFSUMB, WFUMB and from the CEUS LI-RADS working group created a discussion forum to standardize the CEUS examination technique according to published evidence and best personal experience. The goal is to standardise the use and administration of UCAs to facilitate correct diagnoses and ultimately to improve the management and outcomes of patients.

Endocavitary contrast-enhanced ultrasound: a technique whose time has come?

Endocavitary use of contrast agents in sonography (US) is a relatively new method in diagnostic imaging, competing against gray-scale US, fluoroscopy, and endoscopy. This article describes established indications, demonstrates the techniques of evolving applications, and discusses their potential benefits. These benefits include the ability to obtain precise information about the placement of drains and the extent of fluid collections, and to accurately identify the location and features of strictures in various organs, and those of complications of fluid collections or abscesses, without resorting to ionizing radiation.

Transperineal ultrasonography as a complementary diagnostic tool in identifying acute perianal sepsis

BACKGROUND

Successful anal fistula care in complex cases can be assisted by specialized imaging which accurately defines the site of the internal fistula opening and the fistula type. There are currently limited data concerning the clinical indications for and accuracy of transperineal ultrasound (TP-US) in acute perianal sepsis. The aims of this study were to compare the anatomical interpretation of TP-US images with magnetic resonance imaging (MRI) and surgical findings in an unselected patient cohort presenting with acute perianal sepsis.

METHODS

Sixty-seven consecutive patients with acute anorectal sepsis referred from the surgical department were examined using TP-US and Gadolinium-enhanced MRI with both examiners blinded to the surgical results. Fistulae were categorized by the Parks' classification of fistula type.

RESULTS

Thirty-six abscesses were detected by MRI, 38 by TP-US and 30 by surgical examination. Operatively discordant cases showed only ischiorectal panniculitis. TP-US was more accurate in the diagnosis of superficial sepsis and MRI in the diagnosis of deep-seated perirectal infection. TP-US and MRI show concordance with operative findings in fistula diagnosis with a tendency for TP-US to overdiagnose trans-sphincteric fistulae and MRI to over diagnose extra-sphincteric fistulae. Comparison of TP-US with MRI showed good agreement for perianal abscess diagnosis (τ = 0.82) and for fistula diagnosis (τ = 0.68). For fistulae, TP-US showed moderate agreement with surgery (τ = 0.43) with only fair agreement between MRI and surgery (τ = 0.29).

CONCLUSIONS

Transperineal ultrasound complements other imaging modalities in the anatomical diagnosis of acute perianal abscesses and fistulae. It has specific advantages over other techniques and is accurate in the detection of superficially located perirectal sepsis showing concordance with MRI and surgical findings.

A diagnostic accuracy meta-analysis of endoanal ultrasound and MRI for perianal fistula assessment

BACKGROUND

Imaging modalities such as endoanal ultrasound or MRI can be useful preoperative adjuncts before the appropriate surgical intervention for perianal fistulas.

OBJECTIVES

We present a systematic review of published literature comparing endoanal ultrasound with MRI for the assessment of idiopathic and Crohn's perianal fistulas.

DESIGN

A meta-analysis was performed to obtain pooled values for specificity and sensitivity.

SETTINGS

Electronic databases were searched from January 1970 to October 2010 for published studies.

PATIENTS AND INTERVENTIONS

Four studies were used in our analysis. There were 241 fistulas in the ultrasound group and 240 in the magnetic resonance group.

RESULTS

The combined sensitivity and specificity of magnetic resonance for fistula detection were 0.87 (95% CI: 0.63-0.96) and 0.69 (95% CI: 0.51-0.82). There was a high degree of heterogeneity between studies reporting on MRI sensitivity (df = 3, I = 93%). This compares to a sensitivity and specificity for endoanal ultrasound of 0.87 (95% CI: 0.70-0.95) and 0.43 (95% CI: 0.21-0.69). There was a high degree of heterogeneity between studies reporting on endoanal ultrasound sensitivity (df = 3, I = 92%).

CONCLUSIONS

From the available literature, the summarized performance characteristics for MRI and endoanal ultrasound demonstrate comparable sensitivities at detecting perianal fistulas, although the specificity for MRI was higher than that for endoanal ultrasound. Both specificity values are considered to be diagnostically poor, however. The high degree of data heterogeneity and the shortage of applicable studies precludes any firm conclusions being made for clinical practice. Future trials with improved study design (including prospective data collection and consideration of verification bias) may help to further clarify the role of MRI in the assessment and treatment response monitoring of perianal fistulas (particularly in patients with Crohn's disease).

Ultrasonographic assessment of patients referred with chronic anal pain to a tertiary referral centre

BACKGROUND

Chronic anal pain is relatively common as a presentation to specialist physicians and surgeons. Currently, it is regarded as a functional disorder upon the exclusion of occult intersphincteric sepsis. Our study assessed an unselected cohort of patients presenting with chronic previously undiagnosed anal pain using routine ultrasonography.

METHODS

All patients referred to a tertiary gastroenterology service between January 2005 and January 2008 with a diagnosis of chronic anal pain (>3 months duration with no clinical anorectal signs) underwent endoanal and static and dynamic transperineal ultrasound to assess for the frequency and pattern of occult intersphincteric sepsis.

RESULTS

Of 1,580 patients referred, there were 146 presenting with chronic anal pain as a main symptom. Of these, 37 (25.3%) had intersphincteric sepsis (ISS) diagnosed with ultrasound examination with 17 undergoing evaluable surgery. There was a male preponderance (70.3%) with the diagnosis being made in 46% of cases after 6 months of symptoms and with 80.8% having posteriorly located sepsis. This occurred on a background of 62% having previous acute proctological conditions. There was complete ultrasonographic and operative concordance with 15 becoming asymptomatic after surgery at a mean follow-up of 6 months.

CONCLUSION

Occult intersphincteric sepsis is not uncommon and is diagnosed using routine ultrasonography at the time of clinical presentation. Endoanal and transperineal ultrasound is recommended as part of the investigative armamentarium to exclude categorization as functional anorectal pain. This is currently not part of the Rome III coding for such a diagnosis suggesting a revision of these diagnostic criteria for the ultimate diagnosis of functional proctalgia.

Current techniques in imaging of fistula in ano: three-dimensional endoanal ultrasound and magnetic resonance imaging

Perianal fistula is an abnormal communication between the anal canal and perianal skin. The majority of perianal fistulous disease results from either cryptoglandular inflammation or Crohn's disease. These groups differ in pathophysiology, prognosis, and strategies for imaging and treatment. Endoanal ultrasound and magnetic resonance imaging represent current imaging strategies for evaluating perianal fistulas and may be used alone or in combination. The use of three-dimensional technique and peroxide fistulography optimize the ultrasound evaluation of perianal fistula. The use of multiple imaging planes and sequences including fat suppression and contrast enhancement optimize the magnetic resonance imaging protocol. Examples of the imaging appearance of perianal fistulas and a proposed flowchart for imaging modality selection are provided.

Comparison of accuracy of physical examination and endoanal ultrasonography for preoperative assessment in patients with acute and chronic anal fistula

BACKGROUND

This study was undertaken to evaluate the accuracy of endoanal ultrasonography for preoperative assessment of anal fistula, with special reference to the difference between acute and chronic fistula.

METHODS

The subjects comprised 401 patients treated for acute or chronic anorectal sepsis of cryptoglandular origin during the period January through December 2005. All patients underwent physical examination and endoanal ultrasonography. Agreement between the physical and endosonographic findings and the definitive surgical findings were evaluated with special reference to classification of the primary tract and horseshoe extension and localization of the internal opening. The difference in accuracy of endosonographic assessment between acute and chronic fistula was also evaluated.

RESULTS

The accuracy of endoanal ultrasonography was significantly higher than that of physical examination in detecting the primary tract (88.8% vs. 85.0%, p=0.0287) and horseshoe extension (85.7% vs. 58.7%, p<0.0001) and in localizing the internal opening (85.5% vs. 69.1%, p<0.0001). Furthermore, localization of the internal opening by endosonography was significantly more accurate in chronic fistula than in acute fistula (89.5 % vs. 76.8%, p<0.0001), although the accuracy in detecting the primary tract and horseshoe extension was not significantly different.

CONCLUSIONS

Endoanal ultrasonography is reliable and useful for preoperative assessment of anal fistula, particularly for detecting horseshoe extension and localizing the internal opening. Endosonographic assessment provides clearer depiction of the internal opening during periods of quiescence than during the period of abscess formation. For patients with acute anorectal sepsis, initial surgical drainage and subsequent fistula surgery, rather than one-stage fistula surgery, may be advisable to avoid misidentification of the internal opening.

Endoanal ultrasound in benign anorectal disorders: clinical relevance and possibilities

Endoanal ultrasound is a well-established technique used to evaluate benign anorectal disorders. The technique is easy to perform, has a short learning curve and causes very little discomfort. Reconstruction of 3D images is possible. The clinical indications for endoanal ultrasound in benign anorectal diseases are fecal incontinence and peri-anal fistula. Sphincter defects can be depicted with precision and correlate perfectly with surgical findings. Furthermore, an impression of sphincter atrophy can be established. With perianal fistula the tracts can be visualized. Introducing hydrogen peroxide via the external fistula opening improves imaging. Endoanal ultrasound and MRI have comparable results in diagnosing anorectal disorders.

The role of transperineal ultrasonography in the assessment of the internal opening of cryptogenic anal fistula

PURPOSE

The aim of this study was to assess the reliability of transperineal ultrasonography (TPUS) in the pre-operative identification of the internal opening of anal fistulas compared to conventional proctological examination and operative findings.

METHODS

Forty-three patients with anal fistula were assessed by TPUS with and without the use of hydrogen-peroxide injection (E-TPUS) in an attempt to identify the internal opening. Results were compared to preoperative conventional examination and operative findings.

RESULTS

Operative assessment showed an anterior internal opening in 29 patients (67.4%) and a posterior opening in 14 (32.6%). Compared to the operative findings, the agreement rate for the identification of the internal opening was 74.4% for physical examination alone, 93.0% for TPUS and 90.7% for E-TPUS. Physical examination was less accurate in detecting the internal opening than both TPUS (p=0.014) and E-TPUS (p=0.026).

CONCLUSIONS

TPUS and E-TPUS are superior to physical examination in the identification of internal openings in anal fistulas. Hydrogen peroxide injection does not provide additional advantages.

Sonography of benign conditions of the anal canal: an update

OBJECTIVE

The objective of this article is to describe our experience with sonography for the study of benign conditions of the anal canal and perianal soft tissues.

CONCLUSION

Assessment of the anal sphincters in patients with fecal incontinence and documentation of perianal inflammatory masses and tracts in those with perianal inflammatory disease are the major indications for imaging the anal canal. We augment traditional transanal sonography with transperineal scanning in both sexes and transvaginal scanning in women to better show the anal canal in its quiet state to allow an accurate assessment of the integrity of the anal sphincters and of evidence of acute or chronic inflammatory involvement.

Simple clinical examination predicts complexity of perianal fistula

OBJECTIVE

To investigate the diagnostic value of the distance between external opening of perianal fistula and anal verge and to evaluate its relation to the type of fistula. Preoperative identification of complex fistulae is important for proper planning of treatment.

PATIENTS AND METHODS

One hundred and fifteen consecutive patients operated for perianal fistula were studied prospectively. The distance between the external opening and the anal verge was measured. Location of the external opening, demographic and medical history data were correlated with characteristics of the fistulae. Data analysis was performed using the SPSS statistical package. The association between categorical variables was examined using the chi(2)-test or Fisher's exact test for small sample. Comparison of continuous variables between two groups was analysed by t-test.

RESULTS

The mean distance between external opening and anal verge in simple fistulae was 2.8 cm (range 1.5-4.3, SD 0.689) and in complex fistulae it was 4.4 cm (range 3.5-6.0, SD 0.526). This difference was statistically significant -P < 0.0001. Age and previous operations (particularly attempted definitive operations) were also significantly related to the complexity of the fistula. Data concerning location and direction of the fistulous tracts confirm the validity of Goodsall's rule.

CONCLUSION

Simple preoperative clinical examination may reliably predict the complexity of a perianal fistula. Identification of these patients permits to select the cases that should have specific sophisticated preoperative work-up. The first definitive operation is most important to assure a successful outcome, thus such preoperative triage may also permit selective referral to a specialized colorectal team.

Imaging of fistula in ano

Fistula in ano is a common condition that often recurs despite seemingly adequate surgery, usually because of infection that was missed at surgery. It is now increasingly recognized that preoperative imaging can help identify infection that would have otherwise gone unidentified. In particular, magnetic resonance (MR) imaging findings have been shown to influence surgery and markedly diminish the chance of recurrence; thus, preoperative imaging will become increasingly routine in the future. In this article, the authors describe the pathogenesis, classification, and imaging of fistula in ano, with an emphasis on MR imaging. Most important, the authors describe how the radiologist is well placed to answer the surgical riddles that must be solved for treatment to be effective.

The use of intra-operative endo-anal ultrasound in perianal disease

INTRODUCTION

Endoanal ultrasound (EAUS) has demonstrated high sensitivity and specificity for the structural imaging of anorectal pathology. This study prospectively assessed the impact of intra-operative EAUS on the surgical management of perianal disease.

METHODS

EAUS was performed prior to and after examination under anaesthesia (EUA) in a consecutive series of patients with perianal disease. The impact of EAUS on the surgery performed was identified.

RESULTS

Forty-three procedures have been performed in 38 patients (21 male, 17 female; mean age 42.7 years, range 6-76 years) over a three year period. Pathologies encountered were fistula-in-ano (42%), fissure-in-ano (26%), complicated perianal sepsis (16%) and carcinoma (5%). No specific abnormality was identified in 5 symptomatic patients (12%). Four patients with fissures had undergone previous sphincterotomy. In 22 cases (51.2%) the EAUS findings affected the surgical management (extent of muscle above a fistula 9 cases, extent of sphincterotomy 7 cases, site of sepsis identified 2 cases, exclusion of sepsis 2 cases, assessment of cancer resectability 1 case, biopsy of intersphincteric lesion 1 case).

CONCLUSION

Intra-operative EAUS accurately identifies perianal disease and influences the surgical procedure performed. While not essential, it is a useful adjunct especially in recurrent perianal sepsis, undiagnosed anorectal pain and anal fissure.

Transcutaneous perianal sonography: A sensitive method for the detection of perianal inflammatory lesions in Crohn’s disease

AIM: Pelvic magnetic resonance imaging (MRI) and endoanal ultrasound which are established imaging methods for perianal inflammatory lesions in patients with Crohn’s disease require expensive specialized equipments and expertise. We investigated the feasibility and sensitivity of transcutaneous perianal ultrasound (PAUS) using regular ultrasound probes in the imaging of perianal inflammatory lesions. The sonographic findings were correlated to pelvic MRI-scans.

METHODS: We performed PAUS in 25 patients with Crohn’s disease and clinical signs of perianal inflammatory disease. Within a median of 10 d (range 0-75) these patients underwent MRI of the pelvis. Regular convex and linear high resolution probes were used for PAUS. The sonographic findings were correlated to the MRI findings by blinded investigators.

RESULTS: The sonographic investigations were well tolerated by all patients. Fistulae typically presented as hypoechoic tracks. Twenty-nine fistulae were detected in 22 patients. Abscesses were detected in 7 patients and presented as hypo- or anechoic formations. Twenty-six of 29 fistulae and 6 of 7 abscesses could be confirmed by MRI. Kappa statistics showed an excellent agreement (kappa > 0.83) between the two imaging methods.

CONCLUSION: PAUS is a simple, painless, feasible, real-time method that can be performed without specific patient preparation which is comparable in its sensitivity to pelvic MRI in the detection of perianal fistulae and/or abscesses. PAUS can especially be recommended as a screening tool in acute perianal disorders such as perianal abscess and for follow-up studies of perianal inflammatory disease.