Hydrogen peroxide-enhanced three-dimensional endoanal ultrasonography and endoanal magnetic resonance imaging in evaluating perianal fistulas: agreement and patient preference

Comparison of MRI and Endoanal Ultrasound in Assessing Intersphincteric, Transsphincteric, and Suprasphincteric Perianal Fistula

OBJECTIVES

Perianal fistula is a common disorder characterized by an anomalous perianal track connecting two epithelialized surfaces, most commonly the anal canal and the perianal skin. Although each has its limitations, magnetic resonance imaging (MRI) and endoanal ultrasound are currently two acceptable modalities for assessing perianal fistula. This study aimed to evaluate the accuracy of MRI and endoanal ultrasonography in diagosing perianal fistula, considering the surgical results as the references.

METHODS

This prospective cohort study was performed on patients with symptomatic perianal fistulas. MRI results of patients reported by the radiologist were collected along with the findings of endoanal ultrasonography performed by a gastroenterologist. These results were compared with surgical findings as the reference standard.

RESULTS

The study enrolled 126 patients. Exactly 222 definitive fistulas were identified during surgery. Sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of ultrasound for perianal fistula were 87.38, 38.46, 92.38, 26.31, and 82.25% respectively; and for MRI were 76.12, 57.69, 93.88, 22.05, and 74.19% respectively. The accuracy of endoanal ultrasound for detecting transsphincteric and intersphincteric fistulas was higher than MRI. In contrast, the diagnostic value of MRI for detecting suprasphincteric fistulas was higher than endoanal ultrasound.

CONCLUSIONS

Using endoanal ultrasonography to diagnose perianal fistulas is a relatively accurate method. This method may be more sensitive than MRI in detecting patients with perianal fistulas and abscesses.

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.

Clinicopathological determinants of recurrence after surgical treatment of fistula-in-ano in a Ghanaian teaching hospital

AIM

The aim of this work is to describe the clinicopathological and surgical aspects of fistula-in-ano and assess the risks associated with recurrence of the disease in a Ghanaian teaching hospital.

METHOD

This was a retrospective observational study assessing all fistula-in-ano surgeries performed at the Korle Bu Teaching hospital from January 2014 to January 2021 that had completed follow up of at least 3 months after wound healing. Demographic, clinical, pathological and surgical data were extracted from patient records. Logistic regression analysis was used to test for association between these variables and recurrence.

RESULTS

A total of 105 patients underwent 124 fistula surgeries. Their median age was 41 years, the male:female ratio was 4:1 and 12 had comorbidities including human immunodeficiency virus infection and diabetes mellitus. Thirty-one per cent (39/124) of fistulas had previously been operated on. At surgery, 51% (64/124) of fistulas followed a single straight tract, 30% (37/124) a single curved tract and 19% (23/124) had multiple curved tracts. More than half (65/124) were trans-sphincteric, 35% (44/124) suprasphincteric, 10% (12/124) subsphincteric and 2% (3/124) were intersphincteric. Sixty per cent of fistulas were treated with a ligation of intersphincteric fistula tract (74/124), 35% (44/124) a fistulectomy and 5% a fistulotomy. Recurrence after surgery was 22.5% (28/124); this was significantly higher for fistulas with multiple curved tracts (OR 4.153, 95% CI 1.431-12.054, p = 0.012) and fistulas with comorbidities (OR 3.222, 95% CI 1.076-9.647, p = 0.037).

CONCLUSION

There was high recurrence after fistula surgery with increased risk for fistulas with multiple tracts and the presence of comorbidities.

Endoscopic Evaluation and Management of Perianal Disease

Perianal Crohn's disease is associated with decreased quality of life, high morbidity, and high health care use. Treatment goals are to provide infection control, stop fistula drainage, and heal fistula tracts while preserving the anorectal sphincter. Treatment includes a combination of medical and surgical intervention, but new techniques are using interventional endoscopy to act as either a bridge to surgery or to decrease the need for surgical intervention. The decision on which approach to pursue requires knowledge of prior surgery, altered anatomy, prior fistula treatment, and imaging and endoscopic evaluation of fistula complexity, mucosal involvement, and associated stricture or abscess.

Three-dimensional endoanal ultrasound to assess the validity of Goodsall's Rule and the Midline Rule in predicting the path of perianal fistula-in-ano and the location of the internal opening

BACKGROUND

Correct identification of the internal opening is essential in the management of perianal fistulae. The aim of this study was to assess the validity of Goodsall's Law and the Midline Rule in predicting the path of perianal fistula-in-ano and the location of the internal opening using 3-dimensional endoanal ultrasound.

METHODS

An observational study including patients diagnosed with fistula-in-ano, at our institution from January 2006 to December 2020 was performed. Location and distance from the anal verge of the external opening, internal opening, and the path of the fistulous tract were recorded during physical examination and endoanal ultrasound. Goodsall's and Midline rules were applied to all fistulae according to the location of the external opening. The location of the internal opening as predicted by either rule was then compared to the real location of the internal opening identified during endoanal ultrasound examination.

RESULTS

Nine hundred and nine patients [657 (72.3%) males, mean age 50.78 (49.84-51.72) years] were included. 665 (73.2%) of fistulae were transsphinteric. Concordance between predicted internal opening site and the true internal opening location was 0.601 (good match) for Goodsall's rule, and 0.416 (moderate match) for the Midline rule. Goodsall's rule proved to be more predictive in the anterior plane (p < 0.001). Both rules were more likely to make a correct diagnosis in posterior fistulae located 4.5-7.5 mm from the anal verge.

CONCLUSIONS

Both Midline and Goodsall's rules are highly predictive of the course of fistula tracts located in the posterior plane, and are lower for anterior located fistulae, female patients and when the external opening is located further from the anal verge.

Establishing the normal ranges of female and male anal canal and rectal wall vascularity with color Doppler anorectal ultrasonography

Study objectives To evaluate blood supply in the anal canal, rectal wall and mesorectal fat of men and women, using color Doppler endorectal sonography to establish normal ranges for vascular parameters.

Methods A prospective cross-sectional study conducted at a tertiary-care hospital recruited asymptomatic volunteers (≤50 years). Vascularity percentage and index were calculated for defined regions.

Results Vascularity percentage and index were significantly higher in the puborectalis, mid-level external and upper internal anal sphincter compared to the low anal canal; these parameters were higher in men than in women at upper and middle levels of the inner anal canal structures. At mid-level, vascularity was greater in the external compared to the internal anal sphincter in both sexes; however, at the upper level it was greater in the puborectalis compared to the internal anal sphincter in women. Vascularity was greater in the rectal wall compared to the mesorectal fat, with no difference between middle and lower levels.

Conclusions Blood supply is highest at upper levels of the anal canal; however, inner structures are better irrigated in men. Moreover, the rectal wall is better irrigated than the mesorectal fat. Establishing normal ranges may permit future comparisons of the studied structures in disease states as well as the hormonal and age related changes.

Anatomical characteristics of anal fistula evaluated by three-dimensional anorectal ultrasonography: is there a correlation with Goodsall's theory?

Purpose We aimed to correlate the course of the anal fistula tract (T), location of the external opening (EO) and internal opening (IO) in anterior (A) and posterior (P) circumference using 3D-US according to Goodsall's rule.

Methods 151 patients with primary cryptoglandular Transsphincteric fistulas were examined with 3D-US and compared with surgical finding. The type of the T (straight or curved), EO and IO were identified and divided into 3 Groups: GI: EO and IO are located in a position; GII: EO and IO are located in P position and GIII: OE and OI are located in the opposite position. The findings were correlated with Goodsall's rule.

Results 74/151(49%) were included in GI, of them, 41 (55%) were male (33/44% had straight tract and 8/11% curved) and 33 (45%) female (15/20%-straight and 18/25%-curved). GII included 68 (45%), of them, 50 (74%) were male (39/57%-straight and 11/15%-curved) and 18 (26%) female (14/20%-straight and 04/8%-curved). GIII = 9 (6%) and all of them had curved tract. The overall concordance between 3D-US and surgical finding was 98% for tract and 96% for IO.

Conclusion The 3D-US findings correlate with the Goodsall's rule in transsphincteric fistulas located in the anterior circumference straight type, in male, while in females the distribution of curved and straight paths is similar. In the posterior circumference no correlation was observed in both the sexes.

Using preoperative three-dimensional endoanal ultrasound to determine operative procedure in patients with perianal fistulas

AIM

Accurate preoperative identification of perianal fistula tracts and internal openings can facilitate the choice of surgical procedure and may lead to improved healing rates. Our aim was to explore the effectiveness of three-dimensional endoanal ultrasound (3D-EAUS) in determining the type of perianal fistula and planning operative management.

METHOD

This was a cohort longitudinal study. Patients with perianal fistulas from January 2017 to January 2018 who underwent 3D-EAUS and subsequent surgery were included. Intra-operative findings were considered as standard for comparison with clinical examination and 3D-EAUS findings. The primary outcome measure was to evaluate the concordance between 3D-EAUS and intra-operative findings and the secondary outcome measure was healing rates.

RESULTS

Sixty-eight patients with a mean age of 43.1 ± 14.1 years were included. Twenty-eight patients had inter-sphincteric (41.2%) and 40 (14 high and 26 low) trans-sphincteric fistulas (58.8%). 3D-EAUS, clinical examination and intra-operative exploration could predict the location of internal openings in 62/68 (91.2%), 48/68 (70.5%) and 56/68 (82.4%) patients, respectively. Hydrogen peroxide (H₂O₂)-enhanced 3D-EAUS accurately predicted the location of internal openings when compared with 3D-EAUS without H₂O₂ (concordance K = 0.963, P = 0.05). High concordance rates were seen between intra-operative and 3D-EAUS findings on the type of perianal fistula. No significant difference was seen between the suggested surgical treatment based on 3D-EAUS and the eventual surgical treatment (P > 0.05). Study limitations were the small sample size and lack of randomization.

CONCLUSION

3D-EAUS may be considered as a first-line investigation for patients with perianal fistulas because of high concordance with intra-operative assessment and facilitation of surgical planning.

Advances in Perianal Disease Associated with Crohn's Disease-Evolving Approaches

Perianal diseases, common complications of Crohn's disease, are difficult to diagnose/manage. Patients with perianal Crohn's disease suffer from persistent pain and drainage, recurrent perianal sepsis, impaired quality of life, and financial burden. Conventional medical and surgical therapies carry risk of infection, myelosuppression, incontinence, disease recurrence. Although the phenotype of Crohn's disease has been extensively studied, reported outcomes are inconsistent. Endoanal ultrasonography is also becoming popular because of low cost and ability to acquire images in real time. Emerging management strategies for treatment including laser therapy, local injection of agents, use of hyperbaric oxygen, and stem cell therapy, have demonstrated efficacy.

Effects of preoperative endoanal ultrasound on functional outcome after anal fistula surgery

Objective

Endoanal ultrasound (EAUS) is a recommended preoperative investigation for fistula-in-ano (FiA) which aims to provide the best chance of healing and preservation of continence function. This study aims are (1) to assess effect of EAUS on functional outcome and (2) to determine factors associated with clinical outcomes after FiA surgery.

Design

Retrospective analysis of subjects with cryptogenic FiA between January 2011 and December 2016, in a tertiary hospital, was performed by comparing EAUS and no-EAUS groups. Postoperative change in St. Mark’s faecal incontinence severity score (cFISS=FISS at 6 months after surgery–FISS before surgery) were compared. General linear model was used to determine factors associated with cFISS. Binary logistic regression was used to assess factors related to clinical outcomes. A p-value of <0.05 is considered significant.

Results

We enrolled 339 subjects; 109 (M:F 91:18, mean age 41.7±13.6 years) of 115 in EAUS group and 230 in no-EAUS group (M:F 195:35, mean age 42.6±13.0 years). There were higher proportions of recurrent cases (24.8% vs 13.9%, p=0.014) and complex FiA (80.7% vs 50.4%, p=0.001) in EAUS group. Postoperative FISS (mean±SE) were increased in both groups; preoperative versus postoperative FISS were 0.36±0.20 versus 0.59±0.25 in EAUS group (p=0.056) and 0.31±0.12 versus 0.76±0.17 in no-EAUS group (p<0.001). EAUS had significant effects on cFISS in both univariate analysis, F(1,261)=4.053, p=0.045; and multivariate analysis, F(3,322)=3.147, p=0.025, Wilk’s Lambda 0.972. Other associated factors included recurrent fistula (F(3,322)=0.777, p=0.007, Wilk’s Lambda 0.993) and fistula classification (F(3,322)=16.978, p<0.001, Wilk’s Lambda 0.863). After a mean follow-up of 33.6±28.6 weeks, success rate was 63.3%(EAUS) and 60% (no-EAUS), p=0.822. Factors associated with clinical outcomes were fistula complexity, number of tracts, recurrence, number of previous surgery and type of operations. Accuracy of EAUS was 90.8% and not related to clinical outcomes (p=0.522).

Conclusion

EAUS had favourable effects on functional outcome after FiA surgery while multiple factors were associated with clinical outcomes. EAUS is useful, accurate, inexpensive and can be the first tool for planning of complex and recurrent FiA.

CAN THREE-DIMENSIONAL ANORECTAL ULTRASONOGRAPHY BE INCLUDED AS A DIAGNOSTIC TOOL FOR THE ASSESSMENT OF ANAL FISTULA BEFORE AND AFTER SURGICAL TREATMENT?

BACKGROUND

There is no a clear knowledge concerning the division of any part of the anal sphincter complex and the effect of this procedure on the function of the anal canal during the treatment of perianal fistula.

OBJECTIVE

To evaluate the usefulness of 3D anorectal ultrasound in the assessment of anal fistula, quantifying the length of the sphincter muscle to be transected, selecting patients for different approaches and identifying healing, failure or recurrence after the surgical treatment.

METHODS

A prospective study included patients with primarily cryptogenic transsphincteric anal fistula assessed by fecal Incontinence score, tri-dimensional anorectal ultrasound and anal manometry before and after surgery. Based on 3D-AUS, patients with ≥50% external sphincter or external sphincter+puborectalis muscle involvement in males and ≥40% external sphincter or external sphincter+puborectalis muscle in females were referred for the ligation of the intersphincteric tract (LIFT) or seton placement and subsequent fistulotomy; and with <50% involvement in males and <40% in females were referred to one-stage fistulotomy. After surgery, the fibrosis (muscles divided) and residual muscles were measured and compared with the pre-operative.

RESULTS

A total of 73 patients was included. The indication for the LIFT was significantly higher in females (47%), one-stage fistulotomy was significantly higher in the males (46%) and similar in seton placement. The minor postoperative incontinence was identified in 31% of patients underwent sphincter divided and were similar in both genders. The 3D-AUS identified seven failed cases.

CONCLUSION

The 3D ultrasound was shown to be an effective method in the preoperative assessment of anal fistulas by quantifying the length of muscle to be divided, as the results were similar at the post-operative, providing a safe treatment approach according to the gender and percentage of muscle involvement. Additionally, 3D ultrasound successfully identified the healing tissue and the type of failure or recurrence.

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.

Three-Dimensional Modeling for Crohn's Fistula-in-Ano: A Novel, Interactive Approach

BACKGROUND

Pelvic MRI allows for clear delineation of anatomy in Crohn's fistula-in-ano, although its interpretation is often difficult for nonradiologists.

OBJECTIVE

The aim was to develop a 3-dimensional model where fistula tracts and their relationship to the sphincter complex can be accurately defined, which can then be rotated in multiple axes by the surgeon.

DESIGN

A 3-dimensional model was created based on MRI images. An additional 3-dimensional T2-weighted sequence was added to the existing MRI protocol to obtain high-resolution images. Segmentation of the fistula tract and volume rendering of the segmented tract were performed to create the final model.

SETTINGS

This was a single-center study conducted in Victoria, Australia.

PATIENTS

All of the patients who had pelvic MRI for fistulating Crohn's disease between March 2016 and March 2017 had the additional MRI sequence.

INTERVENTIONS

Postprocessing of MRI images was performed by a single radiologist.

RESULTS

Total acquisition time for MRI images was extended to 31 minutes compared with the standard 2-dimensional protocol lasting 25 minutes. Additional postprocessing time used to create the model was ≈15 minutes. Two clinical vignettes using this model are presented and compared with conventional 2-dimensional MRI images to highlight the use of the 3-dimensional modeling technique.

LIMITATIONS

This technique involves a semiautomatic process of fistula tract segmentation that requires radiologist expertise and additional postprocessing time.

CONCLUSIONS

This 3-dimensional modeling technique enables accurate identification of tracts in Crohn's fistula-in-ano and improves spatial orientation for the surgeon. The model has the potential to be an invaluable preoperative tool to guide operative decision-making, as well as enabling the assessment of response to medical or surgical therapy.

Treatment of Perianal Fistulas in Poland

A perianal fistula is a pathological canal covered by granulation tissue connecting the anal canal and perianal area epidermis. The above-mentioned problem is the reason for the patient to visit the surgeonproctologist. Unfortunately, the disease is characterized by a high recurrence rate, even despite proper management. The aim of the study was to determine the current condition of perianal fistula treatment methods in everyday surgical practice, considering members of the Society of Polish Surgeons.

MATERIAL AND METHODS

1523 members of the Society of Polish Surgeons received an anonymous questionnaire comprising 15 questions regarding perianal fistula treatment in everyday practice.

RESULTS

Results were obtained from 807 (53%) members. After receiving answers, questionnaire results were collected, analysed, and presented in a descriptive form.

CONCLUSIONS

Study results showed that most Polish surgeons choose the fistulectomy/fistulotomy method. Considering treatment of perianal fistulas the most important issue is to find the correct, primary fistula canal. Further methods should be individually selected for each patient. One should also remember that every fistula is different. Surgical departments that operate a small number of perianal fistulas should direct such patients to reference centers.

Three-dimensional endoanal ultrasound for diagnosis of perianal fistulas: Reliable and objective technique

AIM: To evaluate accuracy of three-dimensional endoanal ultrasound (3D-EAUS) as compared to 2D-EAUS and physical examination (PE) in diagnosis of perianal fistulas and correlate with intraoperative findings.

METHODS: A prospective observational consecutive study was performed with patients included over a two years period. All patients were studied and operated on by the Colorectal Unit surgeons. The inclusion criteria were patients over 18, diagnosed with a criptoglandular perianal fistula. The PE, 2D-EAUS and 3D-EAUS was performed preoperatively by the same colorectal surgeon at the outpatient clinic prior to surgery and the fistula anatomy was defined and they were classified in intersphincteric, high or low transsphincteric, suprasphincteric and extrasphincteric. Special attention was paid to the presence of a secondary tract, the location of the internal opening (IO) and the site of external opening. The results of these different examinations were compared to the intraoperative findings. Data regarding location of the IO, primary tract, secondary tract, and the presence of abscesses or cavities was analysed.

RESULTS: Seventy patients with a mean age of 47 years (range 21-77), 51 male were included. Low transsphincteric fistulas were the most frequent type found (33, 47.1%) followed by high transsphincteric (24, 34.3%) and intersphincteric fistulas (13, 18.6%). There are no significant differences between the number of IO diagnosed by the different techniques employed and surgery (P > 0.05) and, there is a good concordance between intraoperative findings and the 2D-EAUS (k = 0.67) and 3D-EAUS (k = 0.75) for the diagnosis of the primary tract. The ROC curves for the diagnosis of transsphincteric fistulas show that both ultrasound techniques are adequate for the diagnosis of low transsphincteric fistulas, 3D-EAUS is superior for the diagnosis of high transsphincteric fistulas and PE is weak for the diagnosis of both types.

CONCLUSION: 3D-EAUS shows a higher accuracy than 2D-EAUS for assessing height of primary tract in transsphincteric fistulas. Both techniques show a good concordance with intraoperative finding for diagnosis of primary tracts.

Fistula in Ano

An accurate delineation of the surgical anatomy of perianal inflammatory disease is vital before surgery to prevent postoperative recurrence and incontinence. The purpose of this study was to evaluate the use of transperineal sonography for evaluating perianal inflammatory disease. Thirty patients (23 males and 7 females) with clinically suspected perianal inflammatory disease were imaged with transperineal sonography in males and transperineal and transvaginal sonography in females. All fluid collections, sinus tracts, and fistulae were evaluated in relation to the sphincters and perineum. Twenty-seven of the 30 patients had fistulae: 7 intersphincteric, 17 transphincteric, and 1 extrasphincteric fistula. Three patients had perianal fluid collections with sinus tracts. Preoperative sonographic findings were confirmed in 23 patients. Thirty-one internal openings seen on sonography were confirmed on surgery. The authors conclude that transperineal and transvaginal sonography are accurate and painless methods for documenting perianal inflammatory disease.

Systematic review of evidence and consensus on perianal fistula: an analysis of national and international guidelines

AIM

Treatment of perianal fistula has evolved with the introduction of new techniques and biologicals in Crohn's disease (CD). Several guidelines are available worldwide, but many recommendations are controversial or lack high-quality evidence. The aim of this work was to provide an overview of the current available national and international guidelines for perianal fistula and to analyse areas of consensus and areas of conflicting recommendations, thereby identifying topics and questions for future research.

METHOD

MEDLINE, EMBASE and PubMed were systematically searched for guidelines on perianal fistula. Inclusion was limited to papers in English less than 10 years old. The included topics were classified as having consensus (unanimous recommendations in at least two-thirds of the guidelines) or controversy (fewer than three guidelines commenting on the topic or no consensus) between guidelines. The highest level of evidence was scored as sufficient (level 3a or higher of the Oxford Centre for Evidence-based Medicine Levels of Evidence 2009, http://www.cebm.net/oxford-centre-evidence-based-medicine-levels-evidence-march-2009/) or insufficient.

RESULTS

Twelve guidelines were included and topics with recommendations were compared. Overall, consensus was present in 15 topics, whereas six topics were rated as controversial. Evidence levels varied from strong to lack of evidence.

CONCLUSION

Evidence on the diagnosis and treatment of perianal fistulae (cryptoglandular or related to CD) ranged from nonexistent to strong, regardless of consensus. The most relevant research questions were identified and proposed as topics for future research.

Endoanal ultrasound in perianal fistulae and abscesses

Endoanal ultrasound is a technique that provides imaging of the anal sphincters and its surrounding structures as well as the pelvic floor. However, endoanal magnetic resonance imaging (MRI) is preferred by most physicians, although costs are higher and demand easily outgrows availability. Endoanal ultrasound is an accurate imaging modality delineating anatomy of both cryptoglandular as well as Crohn perianal fistula and abscess. Endoanal ultrasound is comparable with examination under anesthesia and equally sensitive as endoanal MRI in fistula detection. When fistula tracts or abscesses are located above the puborectal muscle, an additional endoanal MRI should be performed. Preoperative imaging is advocated in recurrent cryptoglandular fistula because a more complex pattern can be expected. Endoanal ultrasound can help avoid missing tracts during surgery, lowering the chance for the fistula to persist or recur. It can easily be performed in an outpatient setting and endosonographic skills are quickly incremented. Costs are low and endoanal ultrasound has the potential to improve outcome of patients with both cryptoglandular and fistulizing Crohn disease; therefore, it values more attention.

MR imaging of perianal fistulas in Crohn's disease: sensitivity and specificity of STIR sequences

INTRODUCTION

Although some studies proved the role of STIR sequences in the evaluation of perianal fistulas in Crohn's Disease (CD), contrast medium is still injected in many institutions since there is not a validated reference MR protocol. Our purpose was to evaluate the role of the STIR sequence in the detection and characterization of perianal fistulae comparing it to the post-contrast T1 sequence and correlating it with rectal examination under anesthesia.

MATERIALS AND METHODS

We retrospectively reviewed all clinical records of 31 CD patients, suspected of having perianal fistulas, who had been submitted to an MR study before and after contrast medium injection and surgical exploration under anesthesia within the same month. Perianal fistulas were classified according to the Parks' criteria. Finally, comparison between STIR and post-contrast T1-weighted fat saturated sequences was done.

RESULTS

29 fistulas were detected in 25 patients who underwent an MR study. There was no significant difference between MR imaging and exploration under anesthesia. For the detection of perianal fistulas of any type, there was a perfect statistical agreement between gadolinium-enhanced and STIR sequences (kappa value = 1).

CONCLUSION

STIR sequences represent a valid alternative to the T1-weighted sequences acquired after the injection of contrast medium, allowing the identification of the primary fistula, any secondary ramification, and complications of the disease.

Impact of three-dimensional endoanal ultrasound on the outcome of anal fistula surgery: a prospective cohort study

AIM

The aim of the study was to evaluate the impact of three-dimensional endoanal ultrasound (3D-EAUS) on postoperative outcome in patients with anal fistula.

METHOD

This prospective study compared clinical and functional outcomes of patients with and without preoperative 3D-EAUS examination 1 year after anal fistula surgery. Patients were prospectively followed and evaluated by a standardized protocol including physical examination, the Wexner Incontinence Score (WIS) and anorectal manometry, at baseline and 1 year after surgery.

RESULTS

A total of 196 patients were enrolled. There were no significant differences in demographic and operative parameters, except for operation time, between the two groups. At 1 year follow-up, the overall recurrence rates were 8.8% (9/102) in the 3D-EAUS group and 13.8% (13/94) in the examination under anaesthesia (EUA) group. In the subgroup of patients with complex fistulae, the recurrence rate was numerically lower in the 3D-EAUS group (12.8% vs 22.5%; P = 0.26). The WIS in the EUA group significantly worsened (0.35 ± 0.94 vs 1.07 ± 1.59; P = 0.003) with a decreased the number of fully continent patients (82.5% vs 55%; P = 0.008) while neither the WIS nor the proportion of fully continent patients changed in the 3D-EAUS group. Fewer patients in the 3D-EAUS group developed incontinence postoperatively (6.7% vs 33.3%; P = 0.012) and they had better maximum resting pressure and maximum squeeze pressure than the EUA group.

CONCLUSIONS

Preoperative use of 3D-EAUS had a favourable impact on the outcome of surgical treatment for anal fistulae, especially in those with complex anal fistula. It should be routinely used in the clinical setting.

Evaluation and management of perianal abscess and anal fistula: a consensus statement developed by the Italian Society of Colorectal Surgery (SICCR)

Perianal sepsis is a common condition ranging from acute abscess to chronic fistula formation. In most cases, the source is considered to be a non-specific cryptoglandular infection starting from the intersphincteric space. The key to successful treatment is the eradication of the primary track. As surgery may lead to a disturbance of continence, several sphincter-preserving techniques have been developed. This consensus statement examines the pertinent literature and provides evidence-based recommendations to improve individualized management of patients.

Role of tridimensional endoanal ultrasound (3D-EAUS) in the preoperative assessment of perianal sepsis

PURPOSE

The aim of this study was to evaluate the accuracy of tridimensional endoanal ultrasound (3D-EAUS) in the diagnosis of perianal sepsis comparing the results with the surgical findings, considered as reference standard.

METHODS

From January 2009 to January 2013, all the patients referred for the assessment and treatment of perianal sepsis with suspected anorectal origin were enrolled in the study. All patients gave informed written consent. Prior to surgery, all the patients underwent anamnestic evaluation, clinical examination, and unenhanced and H2O2-enhanced 3D-EAUS. Surgery was performed by a colorectal surgeon blinded to the 3D-EAUS results.

RESULTS

A total of 212 patients with suspected perianal suppurations were assessed during the study period. In 12 patients, the H2O2-enhanced 3D-EAUS was not performed, and so, they were excluded from the study. Very good agreement between 3D-EAUS and examination under anesthesia (EUA) in the classification of primary fistula tracts (kappa = 0.93) and in the identification of fistula internal opening (kappa = 0.97) was found. There was a good concordance (kappa = 0.71) between 3D-EAUS and surgery in the detection of fistula secondary extensions. The overall sensitivity and specificity of 3D-EAUS in the diagnosis of perianal sepsis were 98.3 and 91.3% respectively.

CONCLUSION

3D-EAUS is a safe and reliable technique in the assessment of perianal sepsis. It may assist the surgeon in delineating the fistula tract anatomy and in determining the origin of sepsis, supporting the preoperative planning of definitive and appropriate surgical therapy.

Management of perianal fistulas in Crohn’s disease: An up-to-date review

Perianal disease is one of the most disabling manifestations of Crohn’s disease. A multidisciplinary approach of gastroenterologist, colorectal surgeon and radiologist is necessary for its management. A correct diagnosis, based on endoscopy, magnetic resonance imaging, endoanal ultrasound and examination under anesthesia, is crucial for perianal fistula treatment. Available medical and surgical therapies are discussed in this review, including new local treatment modalities that are under investigation.

Transrectal ultrasonography of anorectal diseases: advantages and disadvantages

Transrectal ultrasonography (TRUS) has been widely accepted as a popular imaging modality for evaluating the lower rectum, anal sphincters, and pelvic floor in patients with various anorectal diseases. It provides excellent visualization of the layers of the rectal wall and of the anatomy of the anal canal. TRUS is an accurate tool for the staging of primary rectal cancer, especially for early stages. Although magnetic resonance imaging is a modality complementary to TRUS with advantages for evaluating the mesorectum, external sphincter, and deep pelvic inflammation, three-dimensional ultrasonography improves the detection and characterization of perianal fistulas and therefore plays a crucial role in optimal treatment planning. The operator should be familiar with the anatomy of the rectum and pelvic structures relevant to the preoperative evaluation of rectal cancer and other anal canal diseases, and should have technical proficiency in the use of TRUS combined with an awareness of its limitations compared to magnetic resonance imaging.

A global consensus on the classification, diagnosis and multidisciplinary treatment of perianal fistulising Crohn's disease

OBJECTIVE

To develop a consensus on the classification, diagnosis and multidisciplinary treatment of perianal fistulising Crohn's disease (pCD), based on best available evidence.

METHODS

Based on a systematic literature review, statements were formed, discussed and approved in multiple rounds by the 20 working group participants. Consensus was defined as at least 80% agreement among voters. Evidence was assessed using the modified GRADE (Grading of Recommendations Assessment, Development, and Evaluation) criteria.

RESULTS

Highest diagnostic accuracy can only be established if a combination of modalities is used. Drainage of sepsis is always first line therapy before initiating immunosuppressive treatment. Mucosal healing is the goal in the presence of proctitis. Whereas antibiotics and thiopurines have a role as adjunctive treatments in pCD, anti-tumour necrosis factor (anti-TNF) is the current gold standard. The efficacy of infliximab is best documented although adalimumab and certolizumab pegol are moderately effective. Oral tacrolimus could be used in patients failing anti-TNF therapy. Definite surgical repair is only of consideration in the absence of luminal inflammation.

CONCLUSIONS

Based on a multidisciplinary approach, items relevant for fistula management were identified and algorithms on diagnosis and treatment of pCD were developed.

Imaging techniques for assessment of inflammatory bowel disease: joint ECCO and ESGAR evidence-based consensus guidelines

The management of patients with IBD requires evaluation with objective tools, both at the time of diagnosis and throughout the course of the disease, to determine the location, extension, activity and severity of inflammatory lesions, as well as, the potential existence of complications. Whereas endoscopy is a well-established and uniformly performed diagnostic examination, the implementation of radiologic techniques for assessment of IBD is still heterogeneous; variations in technical aspects and the degrees of experience and preferences exist across countries in Europe. ECCO and ESGAR scientific societies jointly elaborated a consensus to establish standards for imaging in IBD using magnetic resonance imaging, computed tomography, ultrasonography, and including also other radiologic procedures such as conventional radiology or nuclear medicine examinations for different clinical situations that include general principles, upper GI tract, colon and rectum, perineum, liver and biliary tract, emergency situation, and the postoperative setting. The statements and general recommendations of this consensus are based on the highest level of evidence available, but significant gaps remain in certain areas such as the comparison of diagnostic accuracy between different techniques, the value for therapeutic monitoring, and the prognostic implications of particular 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).

Three-dimensional endoanal ultrasonography in daily proctological practice

Three-dimensional endoanal ultrasonography (3D-EAUS) provides unequalled quality in terms of the anatomical image of the anal canal and sphincter complex. In less than one minute it produces a three-dimensional "cube" that can be manipulated in all spatial dimensions, then archived. In just a few years it has become a new gold standard exploration in proctology. In addition to image quality, 3D-EAUS has the advantage of being easily and rapidly performed, well-tolerated and moderate in cost. For anal incontinence, 3D-EAUS contributes to the identification of sphincter defects. The anatomy of the sphincters can be evaluated spatially. Simple scoring systems with good reproducibility and readily applicable in routine practice can be used to evaluate the "damaged" sphincter volume. For the management of anoperineal suppurations, 3D-EAUS provides information on the fistulous track(s) and on potential collections. These data are crucial as the choice of treatment and its efficacy depend on accurate topographic assessment of the suppuration and the state of the sphincter apparatus.

The accuracy of a postprocessing technique--volume render mode--in three-dimensional endoanal ultrasonography of anal abscesses and fistulas

OBJECTIVE

This study aimed to evaluate the accuracy of a 3-dimensional volume render mode endoanal ultrasonography in the assessment of anal abscesses and fistulas.

PATIENTS AND METHODS

Three-dimensional endoanal ultrasonography was performed preoperatively in 62 patients with clinical diagnoses of an anal abscess and/or an anal fistula. The accuracy of a volume render mode endoanal ultrasonography was evaluated blindly by 2 observers through a retrospective analysis of all the stored images of anal abscesses and fistulas. Differences in classification of the type of anal abscesses and in determination of the type and location of internal openings of anal fistulas were assessed.

RESULTS

In classification of the primary tract, the agreement between the volume render mode endoanal ultrasonography and surgery was much higher than that for the 3-dimensional endoanal ultrasonography (marginal homogeneity test P > .1, κ = 0.96, and marginal homogeneity test P = .0048, κ = 0.28, respectively). In localizing the internal openings and in classifying anal abscesses, the agreement for both methods with surgery was identical. The interobserver agreement showed complete agreement (100%) with regard to luminance and thickness parameters and very high accuracy for the opacity and filter parameters.

CONCLUSIONS

This study demonstrated that volume render mode endoanal ultrasonography is a useful adjunct method to the 3-dimensional endoanal ultrasonography, showing better classification results of the types of anal fistulas.

The role of 3-dimensional anorectal ultrasonography in the assessment of anterior transsphincteric fistula

PURPOSE

The aim of this study was to evaluate the role of 3-dimensional anorectal ultrasonography in the choice of surgical technique according to the position of the fistulous tract in patients with anterior transsphincteric anal fistula.

METHODS

A total of 33 patients (18 male) with anterior transsphincteric fistulas were evaluated by ultrasonography. The length of the external and internal anal sphincters, the position of the internal opening, the length of the compromised sphincter, and the percentage of sphincter muscle to be transected during surgery were measured, compared between sexes, and used in planning the surgery. Postoperative incontinence symptoms were quantified with a Wexner score.

RESULTS

The external and internal sphincters were longer and the position of the internal opening was higher in males. The position where the tract crossed the external sphincter was in both sexes, but the percentage of compromised muscle was higher in females because of the smaller length of the external sphincter. Seton placement followed by fistulotomy or advanced flap repair were indicated in 11 of 18 males and 13 of 15 females as the tract crossed the external sphincter above 50.0%. The mean postoperative follow-up was 12 months. Overall, minor fecal incontinence symptoms were identified in 16 (48.0%) patients. Of these, 11 (73.0%) females and 5 (28.0%) males had a mean incontinence score of 2.9 and 3.0, respectively.

CONCLUSIONS

Three-dimensional ultrasonography was shown to be useful in the preoperative assessment of anterior transsphincteric fistulas by quantifying the length of muscle to be transected, contributing to the choice of a safe treatment approach and to the reduction of the rate of postoperative continence disorders.

[Evaluation of three-dimensional endoanal endosonography of perianal fistulas and correlation with surgical findings]

OBJECTIVE

This study aims to assess the accuracy of three-dimensional endoanal ultrasound (3D-US), two-dimensional ultrasound (2D-US) and physical examination (PE) for the diagnosis of perianal fistulas and correlate the results with intraoperative findings.

MATERIALS AND METHODS

A prospective, observational study with consecutive inclusion of patients was performed between December 2008 and August 2009. Twenty-nine patients diagnosed with a perianal fistula due to undergo surgery were included. All patients underwent PE, 2D-US and 3D-US, and the results were compared to intraoperative findings. The examinations were repeated with hydrogen peroxide instilled through the external opening.

RESULTS

Internal opening (IO): no significant differences with regards to the number of IO diagnosed by PE and 2D-US or 3D-US (P>0.05). Primary tract: good concordance between 3D US and surgery (k=0.61), and this was higher than any of the other techniques used (PE: k=0.41; 2D-US: k=0.56). Secondary tracts: both 2D and 3D-US show good concordance with surgery (86%, k=0.66; 90%, k=0.73, respectively). Abscesses/cavities: The ultrasound examinations showed a moderate concordance with surgery (k=0.438, k=0.540, respectively).

CONCLUSIONS

3D-US shows a higher diagnostic accuracy than 2D-US when compared with surgery to estimate primary fistula height in transphincteric fistulas. 3D-US shows good concordance with surgery for diagnosing primary and secondary tracts and a high sensitivity and specificity for diagnosis of the IO. There was a tendency to overestimate fistula height with 2D-US as shown by the lower specificity of 2D-US for the diagnosis of high transphincteric fistulas and lower sensitivity of 2D-US for low transphincteric fistulas.

Anorectal Crohn's disease

Crohn's disease manifests with perianal or rectal symptoms in approximately one-third of patients, and is associated with a more aggressive natural history. Due to the chronic relapsing nature of the disease, surgery has been traditionally avoided. However, combined medical and surgical intervention when treating perianal fistulae has been shown to offer the best chance for success. Endoanal ultrasound examination or pelvic magnetic resonance imaging should be done in conjunction with an examination under anesthesia to characterize the disease. Any abscess should be drained and setons placed if there is active rectal inflammation or complex fistulae. Antibiotics and immunosuppressive therapy (especially with infliximab) should also be initiated. Simple fistulae can be treated surgically by fistulotomy or anal fistula plug. Complex fistulae can be closed with either an anal fistula plug or covered with flaps. Up to 20% of patients anorectal Crohn's disease require proctectomy for persistent and disabling disease.

Three-dimensional endoanal ultrasonographic assessment of an anal fistula with and without H2O2 enhancement

AIM: To evaluate the effectiveness of three-dimensional endoanal ultrasound (3D-EAUS) in the assessment of anal fistulae with and without H₂O₂ enhancement.

METHODS: Sixty-one patients (37 males, aged 17-74 years) with anal fistulae, which were not simple low types, were evaluated by physical examination and 3D-EAUS with and without enhancement. Fistula classification was determined with each modality and compared to operative findings as the reference standard.

RESULTS: The accuracy of 3D-EAUS was significantly higher than that of physical examination in detecting the primary tract (84.4% vs 68.7%, P = 0.037) and secondary extension (81.8% vs 62.1%, P = 0.01) and localizing the internal opening (84.2% vs 59.7%, P = 0.004). A contrast study with H₂O₂ detected several more fistula components including two primary suprasphincteric fistula tracks and one supralevator secondary extension, which were not detected on non-contrast study. However, there was no significant difference in accuracy between 3D-EAUS and H₂O₂-enhanced 3D-EAUS with respect to classification of the primary tract (84.4% vs 89.1%, P = 0.435) or secondary extension (81.8% vs 86.4%, P = 0.435) or localization of the internal opening (84.2% vs 89.5%, P = 0.406).

CONCLUSION: 3D-EAUS was highly reliable in the diagnosis of an anal fistula. H₂O₂ enhancement was helpful at times and selective use in difficult cases may be economical and reliable.

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.

Effects of age and gender on three-dimensional endoanal ultrasonography measurements: development of normal ranges

BACKGROUND

Faecal incontinence is a common and morbid disorder that is often related to anal sphincter dysfunction. High-frequency, three-dimensional (3-D) endoanal ultrasonography (EAUS) allows greater spatial resolution and longitudinal appreciation of the anal canal than conventional 2-D assessment. A robust normal range of values allowing for age and sex is required for subsequent disease comparison.

METHODS

A group of 30 healthy male (n=12) and female (n=18) volunteers (median age, 49 years; range, 31-63 years) underwent 3-D EAUS using a high-frequency 10-MHz transducer. A reconstructed data cube was interrogated to measure anal canal structures in 2-D at high, middle and low levels, and in 3-D for longitudinal measurements.

RESULTS

Men had a significantly longer 3-D external anal sphincter (EAS) and internal anal sphincter (IAS) than women, especially the anterior EAS (mean in men 2.5 cm, mean in women 1.6 cm, p<0.0001). There were no significant differences between the sexes for anal canal length or by 2-D scanning for the thickness of the EAS and IAS. No significant differences were observed between parous and nulliparous women. Age had no significant effect on 3-D length measurements, but 2-D EAUS measurements of the thickness of both the IAS and EAS increased with age significantly (mid canal, p=0.004). On these bases, normal ranges were generated.

CONCLUSIONS

Sphincter measurements, enabled by 3-D reconstruction, vary with age and sex. A normal range incorporating these variations has been produced for future data comparison in disease states.

The role of three-dimensional endoluminal ultrasound imaging in the evaluation of anorectal diseases: a review

BACKGROUND

The authors conducted a review of the available English literature to evaluate the advantages of three-dimensional ultrasound for assessing anorectal pathology, to provide a state-of-the-art approach, and to compare this technique with conventional endoluminal ultrasound and other imaging methods.

METHODS

All studies describing results obtained with three-dimensional ultrasound in the evaluation of anorectal pathologies, both alone and compared with other techniques, were selected.

RESULTS

Since 1996, 32 articles have been published. In tumor staging, specific data derived by three-dimensional reconstruction for the assessment of T invasion and nodal involvement were more accurate than endoluminal ultrasound and computed tomography. For evaluating perianal sepsis, the detection of secondary fistula tracts and fluid collections and the location of internal openings were superior to endoanal magnetic resonance imaging. In the evaluation of anal incontinence, the results for sphincter defects were similar to those obtained with endoanal magnetic resonance imaging.

CONCLUSION

Analysis of the literature confirmed that three-dimensional ultrasound is a valuable technique for assessing anorectal disorders, facilitating the interpretation of the images obtained, and providing additional data that in many cases have changed the operative approach.

Referral for anorectal function evaluation is indicated in 65% and beneficial in 92% of patients

AIM: To determine the indicated referrals to a tertiary centre for patients with anorectal symptoms, the effect of the advised treatment and the discomfort of the tests.

METHODS: In a retrospective study, patients referred for anorectal function evaluation (AFE) between May 2004 and October 2006 were sent a questionnaire, as were the doctors who referred them. AFE consisted of anal manometry, rectal compliance measurement and anal endosonography. An indicated referral was defined as needing AFE to establish a diagnosis with clinical consequence (fecal incontinence without diarrhea, 3^rd degree anal sphincter rupture, congenital anorectal disorder, inflammatory bowel disease with anorectal complaints and preoperative in patients for re-anastomosis or enterostoma, anal fissure, fistula or constipation). Anal ultrasound is always indicated in patients with fistula, anal manometry and rectal compliance when impaired continence reserve is suspected. The therapeutic effect was noted as improvement, no improvement but reassurance, and deterioration.

RESULTS: From the 216 patients referred, 167 (78%) returned the questionnaire. The referrals were indicated in 65%. Of these, 80% followed the proposed advice. Improvement was achieved in 35% and a reassurance in 57% of the patients, no difference existed between patient groups. On a VAS scale (1 to 10) symptoms improved from 4.0 to 7.2. Most patients reported no or little discomfort with AFE.

CONCLUSION: Referral for AFE was indicated in 65%. Beneficial effect was seen in 92%: 35% improved and 57% was reassured. Advice was followed in 80%. Better instruction about indication for AFE referral is warranted.

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.

Imaging of perianal Crohn's disease

Perianal fistulas and abscesses are common complications of Crohn's disease, affecting up to 50% of patients during their disease course. Accurate diagnosis and classification of perianal disease is crucial before and during treatment to plan an adequate approach for each patient and to avoid irreversible functional consequences. Although examination under anaesthesia has been considered the gold standard for diagnosis and classification of Crohn's disease perianal fistulas, taken alone it does not have perfect accuracy, stressing the need for concomitant or alternative, non-invasive, methods of evaluation. In this context, imaging modalities assessed for diagnosis, classification and monitoring of Crohn's disease perianal fistulas include pelvic magnetic resonance imaging, anorectal endoscopic ultrasonography, transcutaneous perianal ultrasound, fistulography and computed tomography. In particular, magnetic resonance imaging and endoscopic ultrasonography findings have shown the best accuracy, and the ability to influence therapeutic management of these patients. For transcutaneous perianal ultrasound too, good preliminary data have been reported. This paper reviews the available data on imaging methods for the management of perianal Crohn's disease.

Perianal Crohn's disease

Perianal Crohn's disease in children is a potentially debilitating condition that can precede or follow the intestinal disease component. The perianal abnormalities are varied and can include lesions of the perianal skin or anal canal, abscesses or fistulas, and malignancies. The appropriate management of these problems is predicated on a thorough evaluation of the perineum and anus as well as the remainder of the alimentary tract. Therapy usually includes a combination of antibiotics, immunomodulators, and biologic agents as well as conservative operative procedures. The surgical options are intended to safely ameliorate disease-related symptoms without compromising function or continence.

The advantages of volume rendering in three-dimensional endosonography of the anorectum

Anorectal diseases require imaging for proper case management. At present, endoanal ultrasonography and endorectal ultrasonography have become important parts of diagnostic workup of patients with fecal incontinence, perianal fistulas, and rectal cancer and provides sufficient information for clinical decision-making in many cases. However, with the currently available ultrasonographic equipment and techniques, a good deal of relevant information may remain hidden. The advent of high-resolution three-dimensional endoluminal ultrasound, constructed from a synthesis of standard two-dimensional cross-sectional images, and of "Volume Render Mode," a technique to analyze information inside a three-dimensional volume by digitally enhancing individual voxels, promises to revolutionize diagnosis of pelvic floor disorders. By use of the different postprocessing display parameters, the volume-rendered image provides better visualization performance when there are not large differences in the signal levels of pathologic structures compared with surrounding tissues. The anatomic structures in the pelvis, the axial and longitudinal extension of anal sphincter defects, the anatomy of the fistulous tract in complex perianal sepsis, and the presence of slight or massive submucosal invasion in early rectal cancer may be imaged in greater detail. This additional information will bring an improvement for both planning and conduct of surgical procedures.

Computer-assisted evaluation of perianal fistula activity by means of anal ultrasound in patients with Crohn's disease

OBJECTIVES

Assessment of the activity of perianal fistulas may be of clinical relevance in patients with Crohn's disease. Fistula activity is currently evaluated by means of magnetic resonance imaging; anal ultrasound can also be used, but its diagnostic performance in this setting remains to be defined. Our aims were to evaluate the agreement between clinical examination, magnetic resonance imaging, and anal ultrasound in assessing perianal fistula activity, and to apply computerized analysis to improve the assessment of ultrasound images.

METHODS

Thirty-one consecutive patients with Crohn's perianal fistulas underwent clinical examination, and magnetic resonance and anal ultrasound imaging. Active fistulas were defined as the presence of active drainage or signs of local inflammation on clinical examination, and the definition was confirmed by surgical examination. Activity was assessed on the basis of T2 hyperintensity on magnetic resonance imaging and the degree of hypoechogenicity on anal ultrasound; the anal ultrasound images were also analyzed using dedicated computer image-analysis software.

RESULTS

Twenty-five patients had an active fistula at clinical examination. The agreement between clinical examination and magnetic resonance imaging was good (k-value = 0.739), whereas that with anal ultrasound was only fair (k-value = 0.266-0.294); computer-assisted analysis of the anal ultrasound images improved the agreement from fair to good (k-value = 0.608-0.670).

CONCLUSIONS

Anal ultrasound can be used to assess fistula track activity in patients with Crohn's disease. The diagnostic performance of the technique can be improved to values comparable with those of magnetic resonance imaging by using a computer-assisted evaluation of the anal ultrasound images.

Endosonographic imaging of anorectal diseases

OBJECTIVE

The normal sonographic anatomy of the anorectum, sonographic findings of anorectal diseases, and indications and limitations of endosonography compared with magnetic resonance imaging are reviewed. Methods. Endosonographic imaging was performed with a Siemens (Erlangen, Germany) FI 400 ultrasound scanner with an end-fire 7.5-MHz biplane endorectal probe and a B-K Medical (Sandhoften, Denmark) scanner with an 1850 axial-type side-fire 5.0- to 10.0-MHz rotating endoscopic probe.

RESULTS

Rectal carcinoma appears on endorectal sonography as a low-echogenicity lesion that abruptly interrupts the normal sequence of layers. The internal anal sphincter is seen very clearly on endoanal sonography, and it is easy to appreciate atrophy and small tears of this sphincter. Endoanal sonography cannot accurately show thinning of the external anal sphincter. Peroxide-enhanced endoanal sonography is especially useful for patients with recurrent perianal fistulas in whom scarring should be distinguished from recurrent fistulas and detection of the internal opening. However, sonography does not provide an adequate deep and global display of all adjacent pelvic and perineal spaces.

CONCLUSIONS

Endosonography can accurately stage primary rectal tumors and assess the internal anal sphincter. Peroxide-enhanced 3-dimensional imaging can increase the utility of endoanal sonography in detection and characterization of perianal fistulas and planning of optimal therapy. However, magnetic resonance imaging can be used a complementary modality to endosonography, especially for evaluation of external anal sphincter atrophy and deep pelvic inflammation.