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

Accuracy prediction of Goodsall's rule for anal fistulas of crypotogladular origin, is still standing?

Background

Treatment of anal fistulas is still a challenging task because of high recurrence and risk of incontinence. Identification of internal fistula opening is paramount for successful treatment. Goodsall's rule is commonly used to predict the course of fistula and internal opening. However, its accuracy has been questioned by many investigators and its role became a controversial topic.

Method

This is a case series prospective study in which 320 consecutive patients with anal fistula with Mean age 48.9± 6 years ages (ranges from 16 to 64 years) and mean body mass index 24.8± 5.5 average 18.5-30.6) were enroled. Goodsall's rule was applied to all fistulas according to the site of external fistula opening. Location of internal fistula opening as suggested by Goodsall's rule then compared to the exact location of internal opening identified by perineal or pelvic MRI and intraoperative findings. to assess the accuracy and positive predictive value of the Goodsall's rule in predicting the internal opening of the tract.

Results

The overall accuracy rate, positive predictive value (PPV), sensitivity and specificity of Goodsall's rule in this study were 74.75%, 77.1, 74.5, and 72.05, respectively. The accuracy in predicting the internal fistula opening was 52.4% in anterior tracts and 73% in posterior tracts. Goodsall's rule was found to be more accurate in posterior fistulas than anterior fistulas and in short superficial fistulas rather than in long and high fistulas.

Conclusion

Goodsall's rule was accurate in 74.75% of anal fistulas. It was more accurate for posterior long fistulas and anterior short and superficial fistulas. Patients with long (>3 cm) anterior fistulas defied Goodsall's rule when they found to have fistulas tracking to a midline anterior origin. Further, short posterior fistulas were found to open more commonly in a direct radial course rather to midline posteriorly.

Preoperative Assessment of Perianal Fistulas with Combined Magnetic Resonance and Tridimensional Endoanal Ultrasound: A Prospective Study

BACKGROUND

we designed a prospective study of diagnostic accuracy that compared pelvic MRI and 3D-EAUS with pelvic MRI alone in the preoperative evaluation and postoperative outcomes of patients with perianal fistulas.

METHODS

the sample size was 72 patients and this was divided into two imaging groups. MRI alone was performed on the first group. Both MRI and 3D-EAUS were performed in parallel on the second group. Surgical exploration took place after two weeks and was the standard reference. Park's classification, the presence of a concomitant abscess or a secondary tract, and the location of the internal opening were recorded. All patients were re-evaluated for complete fistula healing and fecal incontinence six months postoperatively. All of the collected data were subjected to statistical analysis.

RESULTS

the MRI group included 36 patients with 42 fistulas. The MRI + 3D-EAUS group included 36 patients with 46 fistulas. The adjusted sensitivity and negative predictive value were 1.00 for most fistula types in the group that underwent combined imaging. The adjusted specificity improved for intersphincteric fistulas in the same group. The adjusted balanced accuracy improved for all fistula types except rectovaginal. The combination of imaging methods showed improved diagnostic accuracy only in the detection of a secondary tract. The healing rate at six months was 100%. Fecal incontinence at six months did not present a statistically significant difference between the two groups (Fisher's exact test p-value > 0.9). Patients with complex perianal fistulas had a statistically significant higher probability of undergoing a second surgery (x2 test p-value = 0.019).

CONCLUSIONS

the combination of pelvic MRI and 3D-EAUS showed improved metrics of diagnostic accuracy and should be used in the preoperative evaluation of all patients with perianal fistulas, especially those with complex types.

Advancements in Rectal Drug Delivery Systems: Clinical Trials, and Patents Perspective

The rectal route is an effective route for the local and systemic delivery of active pharmaceutical ingredients. The environment of the rectum is relatively constant with low enzymatic activity and is favorable for drugs having poor oral absorption, extensive first-pass metabolism, gastric irritation, stability issues in the gastric environment, localized activity, and for drugs that cannot be administered by other routes. The present review addresses the rectal physiology, rectal diseases, and pharmaceutical factors influencing rectal delivery of drugs and discusses different rectal drug delivery systems including suppositories, suspensions, microspheres, nanoparticles, liposomes, tablets, and hydrogels. Clinical trials on various rectal drug delivery systems are presented in tabular form. Applications of different novel drug delivery carriers viz. nanoparticles, liposomes, solid lipid nanoparticles, microspheres, transferosomes, nano-niosomes, and nanomicelles have been discussed and demonstrated for their potential use in rectal administration. Various opportunities and challenges for rectal delivery including recent advancements and patented formulations for rectal drug delivery have also been included.

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.

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.

Current imaging techniques for evaluation of fistula in ano: a review

Background

Fistula in ano is one of the common anorectal disorders which have a tendency to recur specially in complex cases usually due to missed or undetected sepsis at the time of examination or surgery. A correct identification of the primary source of crypt infection along with a complete understanding of the anatomical course of primary and secondary tracks and abscesses is a prerequisite for the successful management of fistula. Preoperative evaluation of fistula in ano using radio-imaging techniques provides a handy insight of fistula anatomy and helps in planning the appropriate treatment strategy. The objective of this article is to review the role of different radio-imaging techniques in the diagnosis and evaluation of fistula in ano along with their advantages and disadvantages over one another.

Main text

A comprehensive literature review was performed searching through the electronic databases as well as the standard textbooks of colorectal surgery. X-rays (plain radiographs and contrast fistulography), computed tomography (CT) scanning, anal endosonography, and magnetic resonance (MR) imaging are the modalities used for preoperative imaging of fistula in ano. Due to low accuracy, X-ray fistulography is not used now for fistula imaging. CT fistulography can be more accurate in cases associated with acute inflammations and abscesses and the fistulas related with inflammatory bowel disease. Anal endosonography and MRI are two of the mostly used and reliable imaging techniques for fistula in ano. Though the use of a 3D technology has improved the accuracy of anal endosonography, MRI is the preferred choice by many. However, various reports have depicted comparable accuracies for both MRI and anal endosonography showing both to be equally sensitive but MRI to be more specific. 3D endoanal ultrasound, on the other hand, is more rapid and can also be used intraoperatively to provide live imaging during surgical exploration.

Conclusion

Complex and recurrent fistula cases should undergo a preoperative imaging to reduce the chances of recurrence. MRI is recommended as the imaging modality of choice for such cases. 3D anal endosonography may however be a good option over MRI owing to its rapidity, availability, and potential of intraoperative assistance during surgery.

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.

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.

Preoperative assessment of simple and complex anorectal fistulas: Tridimensional endoanal ultrasound? Magnetic resonance? Both?

PURPOSE

The purpose of the study is to evaluate the diagnostic value of tridimensional endoanal ultrasound (3D-EAUS) and magnetic resonance (MR) in the preoperative assessment of both simple and complex anorectal fistulas.

METHODS

All the patients referred for the treatment of anal fistulas were enrolled in this study and underwent, as preoperative assessment, anamnestic evaluation, clinical examination, and unenhanced and H2O2-enhanced 3D-EAUS and MR. The results of imaging evaluation were compared with surgical findings, considered as reference standard.

RESULTS

During the study period, 124 patients operated on for anal fistulas underwent complete preoperative imaging assessment. Perfect agreement between 3D-EAUS and surgery in the anal fistulas' severity grading was found (K = 1). The fistulas were classified as simple in 68/126 (53.9%) and complex in 58/126 (46.03%) cases, according to fistulas' Parks' classification and the most recent American Guidelines. In both simple and complex anal fistulas, 3D-EAUS did not show a significantly higher accuracy in the evaluation of internal openings, if compared with MR (P = 0.47; McNemar's Chi-square test). In the complex anal fistulas, MR showed a significantly higher accuracy in the evaluation of secondary extensions if compared with 3D-EAUS (P = 0.041; McNemar's Chi-square test), whereas in the simple anal fistulas, no significant difference was found.

CONCLUSION

In the preoperative work-up of patients with anorectal fistulas, 3D-EAUS may represent the first-line diagnostic tool. In cases of fistulas classified as complex by 3D-EAUS, MR may be indicated as adjunctive diagnostic imaging examination, to more carefully describe the fistulas' complete anatomy.

3D-EAUS and MRI in the Activity of Anal Fistulas in Crohn's Disease

Aim. This study aspires to assess the role of 3D-Endoanal Ultrasound (3D-EAUS) and Magnetic Resonance Imaging (MRI) in preoperative evaluation of the primary tract and internal opening of perianal fistulas, of secondary extensions and abscess. Methods. During 2014, 51 Crohn's disease patients suspected for perianal fistula were enrolled. All patients underwent physical examination with both the methods and subsequent surgery. Results. In the evaluation of CD perianal fistulas, there are no significant differences between 3D-EAUS and MRI in the identification of abscess and secondary extension. Considering the location, 3D-EAUS was more accurate than MRI in the detection of intersphincteric fistulas (p value = 10(-6)); conversely, MRI was more accurate than 3D-EAUS in the detection of suprasphincteric fistulas (p value = 0.0327) and extrasphincteric fistulas (p  value = 4 ⊕ 10(-6)); there was no significant difference between MRI and 3D-EAUS in the detection of transsphincteric fistulas. Conclusions. Both 3D-EAUS and MRI have a crucial role in the evaluation and detection of CD perianal fistulas. 3D-EAUS was preferable to MRI in the detection of intersphincteric fistulas; conversely, in the evaluation of suprasphincteric and extrasphincteric fistulas the MRI was preferable to 3D-EAUS.

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.

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 cryptoglandular supralevator abscesses in the magnetic resonance imaging era: a case series

AIM

The aim of this study is to describe the diagnostic performance of magnetic resonance imaging in the management of supralevator abscess, regarding its origin, location, drainage route, subsequent treatment of the fistula, and long-term results.

METHODS

A retrospective case series including thirteen consecutive patients with cryptoglandular supralevator abscess treated between 2001 and 2011 at a colorectal unit of a tertiary referral center. A magnetic resonance imaging was performed in all patients before surgical drainage, and its usefulness in assessing supralevator abscess origin was analyzed. Short- and long-term results after drainage were also evaluated.

RESULTS

The final diagnosis of supralevator abscess and the location described in the magnetic resonance were confirmed intraoperatively in all patients. An ischiorectal origin was identified in nine patients, and perineal translevator drainage was performed placing a mushroom catheter through the ischiorectal or the postanal space. Four patients underwent secondary treatment of anal fistula: two rectal advancement flap and two non-cutting seton. In the other four patients, an intersphincteric origin was identified and transanal surgical drainage was performed placing a long-term mushroom catheter. Several weeks later, transanal unroofing of the residual cavity was performed and the fistula lay open to the anorectal lumen. In the long-term follow-up (median 61 months), only patients with supralevator abscess of ischiorectal origin in whom fistula was not subsequently treated presented a recurrence of the anal sepsis.

CONCLUSIONS

Magnetic resonance imaging seems essential to clarify the location of supralevator abscess, its origin, and choice of the right drainage route. Subsequent treatment of the fistula is necessary to avoid recurrence.

Endosonography and magnetic resonance imaging in the diagnosis of high anal fistulae - a comparison

Anal fistula is a benign inflammatory disease with unclear etiology which develops in approximately 10 in 100 000 adult patients. Surgical treatment of fistulae is associated with a risk of damaging anal sphincters. This usually happens in treating high fistulae, branched fistulae, and anterior ones in females. In preoperative diagnosis of anal fistulae, endosonography and magnetic resonance imaging play a significant role in planning the surgical technique. The majority of fistulae are diagnosed in endosonography, but magnetic resonance is performed when the presence of high fistulae, particularly branched ones, and recurrent is suspected.

THE AIM OF THIS PAPER

The aim of this paper was to compare the roles of the two examinations in preoperative assessment of high anal fistulae.

MATERIAL AND METHODS

The results of endosonographic and magnetic resonance examinations performed in 2011-2012 in 14 patients (4 women and 10 men) with high anal fistulae diagnosed intraoperatively were subject to a retrospective analysis. The patients were aged from 23 to 66 (mean 47). The endosonographic examinations were performed with the use of a BK Medical Pro Focus system with endorectal 3D transducers with the frequency of 16 MHz. The magnetic resonance scans were performed using a Siemens Avanto 1.5 T scanner with a surface coil in T1, T1FS, FLAIR, T2 sequences and in T1 following contrast medium administration. The sensitivity and specificity of endosonography and magnetic resonance imaging were analyzed. A surgical treatment served as a method for verification. The agreement of each method with the surgery and the agreement of endosonography and magnetic resonance imaging were compared in terms of the assessment of the fistula type, localization of its internal opening and branches. The agreement level was determined based on the percentage of consistent assessments and Cohen's coefficient of agreement, κ. The integrity of the anal sphincters was assessed in each case.

RESULTS

In determining the fistula type, magnetic resonance imaging agreed with intraoperative assessment in 79% of cases, and endosonography in 64% of cases. Endosonography agreed with magnetic resonance in 57% of cases. In the assessment of internal opening, the agreement between endosonography and intraoperative assessment was 65%, between magnetic resonance and intraoperative assessment - 41% and between endosonography and magnetic resonance - 53%. In the assessment of fistula branches, endosonography agreed with intraoperative assessment in 67% of cases, magnetic resonance in 87% of cases, and the agreement between the two methods tested was 67%.

CONCLUSIONS

Magnetic resonance is a more accurate method than endosonography in determining the type of high fistulae and the presence of branches. In assessing the internal opening, endosonography proved more accurate. The agreement between the two methods ranges from 53-67%; the highest level of agreement was noted for the assessment of branching.

Comparison of different magnetic resonance imaging sequences for assessment of fistula-in-ano

AIM: To assess agreement between different forms of T2 weighted imaging (T2WI), and post-contrast T1WI in the depiction of fistula tracts, inflammation, and internal openings with that of a reference test.

METHODS: Thirty-nine consecutive prospective cases were enrolled. The following sequences were used for T2WI: 2D turbo-spin-echo (2D T2 TSE); 3D T2 TSE; short tau inversion recovery (STIR); 2D T2 TSE with fat saturation performed in all patients. T1WI were either a 3D T1-weighted prepared gradient echo sequence with fat saturation or a 2D T1 fat saturation [Spectral presaturation with inversion (SPIR)]. Agreement for each sequence for determination of fistula extension, internal openings, and the presence of active inflammation was assessed separately and blindly against a reference test comprised of follow-up, surgery, endoscopic ultrasound, and assessment by an independent experienced radiologist with access to all images.

RESULTS: Fifty-six fistula tracts were found: 2 inter-sphincteric, 13 trans-sphincteric, and 24 with additional tracts. The best T2 weighted sequence for depiction of fistula tracts was 2D T2 TSE (Cohen’s kappa = 1.0), followed by 3D T2 TSE (0.88), T2 with fat saturation (0.54), and STIR (0.19). Internal openings were best seen on 2D T2 TSE (Cohen’s kappa = 0.88), followed by 3D T2 TSE (0.70), T2 with fat saturation (0.54), and STIR (0.31). Detection of inflammation showed Cohen’s kappa of 0.88 with 2D T2 TSE, 0.62 with 3D T2 TSE, 0.63 with STIR, and 0.54 with T2 with fat saturation. STIR, 3D T2 TSE, and T2 with fat saturation did not make any contributions compared to 2D T2 TSE. Post-contrast 3D T1 weighted prepared gradient echo sequence with fat saturation showed better agreement in the depiction of fistulae (Cohen’s kappa = 0.94), finding internal openings (Cohen’s kappa = 0.97), and evaluating inflammation (Cohen’s kappa = 0.94) compared to post-contrast 2D T1 fat saturation or SPIR where the corresponding figures were 0.71, 0.66, and 0.87, respectively. Comparing the best T1 and T2 sequences showed that, for best results, both sequences were necessary.

CONCLUSION: 3D T1 weighted sequences were best for the depiction of internal openings and active inflammatory components, while 2D T2 TSE provided the best assessment of fistula extension.

Magnetic resonance imaging of the gut: a primer for the luminal gastroenterologist

Magnetic resonance imaging (MRI) is well established for imaging the solid organs of the abdomen and pelvis. In recent years it has been having an increasingly important role in the evaluation of the gastrointestinal (GI) tract. Fluoroscopy and abdominal computed tomography, the traditional mainstays of bowel imaging, remain valuable; however, the contemporary emphasis on decreasing patient radiation exposure is driving practice toward non-ionizing modalities such as MRI. The inherent dynamic properties of MRI, its superior tissue contrast, and cross-sectional capabilities offer additional advantages. Here we review, from esophagus to anus, techniques and indications for MRI of the GI lumen with an emphasis on the normal MRI appearance of the GI tract and commonly encountered pathology.

Ileal pouch-anal anastomosis surgery: anatomy, postoperative complications, and image-guided intervention

Total proctocolectomy with ileal pouch-anal anastomosis (IPAA) surgery has become the surgical procedure of choice for chronic ulcerative colitis and familial adenomatous polyposis. Since its introduction in 1978, the technique of ileal pouch-anal anastomosis has improved and is commonly performed. Although associated with low mortality, postsurgical complications are frequent with which the radiologist should be familiar. An understanding of surgical technique and postsurgical anatomy facilitates the diagnosis of these frequently encountered complications and governs their potential image-guided intervention.

Fistula-in-Ano Complicated by Fournier's Gangrene Our Experience in North-Eastern Region of Nigeria

BACKGROUND

Fistula-in-ano when complicated by Fournier's gangrene is an unusual finding and always carries high morbidity. This study details our experience in managing 10 cases.

METHODS OF STUDY

Case files of all patients managed in University of Maiduguri Teaching Hospital and Federal Medical Center of Yola and Gombe from January, 2007 to December, 2011 were retrieved from Medical Record Departments and other Hospital Records. These were analyzed for demographic, clinical and pathological variables, the type of treatment and follow-up.

RESULTS

A total of 10 men with a mean age of 50.5 years (35-60) were managed in the period of study. Nearly, 50% of the patients were farmers, 30% businessmen and 20% were civil servant. 7 (70%) of these patients presented with Fournier's gangrene within 4 weeks of development of fistula-in-ano and the rest within 8 weeks. 4 (40%) of these patients had inadequate drainage of their perianal abscess and 2 (20%) had incision and drainage. Another 4 (40%) had spontaneously rupture of the perianal abscess. 6 (60%) of the fistula-in-ano was submuscular, 30% subcutaneous and 10% were complex or recurrent. Nearly, 20% of patients had fistulotomy and seton application for adequate drainage. Mucosal advancement flap was performed in 5 (50%) and fistulotomy in 3 (30%) patients. Another 30% had fistulotomy and continuing sitz bath.

CONCLUSION

Cryptoglandular infection is an important cause of perianal abscesses and fistula-in-ano and if poorly managed results in Fournier's gangrene. Early broad spectrum parenteral antibiotic therapy and primary surgical treatment can prevent Fournier's gangrene.

The treatment of anal fistulas with biologically derived products: is innovation better than conventional surgical treatment? An update

New technical approaches involving biologically derived products have been applied in the treatment for anal fistulas in order to avoid the risk of fecal incontinence. The aim of this review was to evaluate the scientific evidence present in the literature regarding these techniques. Trials comparing surgery (fistulotomy, advancement mucosal flap closure and placement of seton) versus fibrin glue, fistula plug or acellular dermal matrix were considered. In fibrin glue versus traditional surgical treatment the healing rate was higher in the surgery group, and the recurrence rate was lower in the traditional surgery group, but these results were not statistically relevant. In acellular dermal matrix (ADM) versus traditional surgical treatment the recurrence rate of fistulas was significantly lower in the ADM group, but non-significant differences were recorded in incontinence and anal deformity. Our review shows that there are no significant advantages of the new techniques involving biologically derived products. Further randomized controlled trials are needed.

Rectal imaging: part 2, Perianal fistula evaluation on pelvic MRI--what the radiologist needs to know

OBJECTIVE

The purpose of this article is to provide an overview of pelvic MRI for the evaluation of perianal fistulas, with a description of the technique, illustration of relevant normal anatomy, and examples of various fistula types.

CONCLUSION

MRI evaluation of perianal fistulas can be challenging, and knowledge of relevant pelvic anatomy and fistula classification remains crucial in the diagnosis. MRI is highly accurate for fistula depiction and, by providing an accurate assessment of disease status and extension, can help surgical planning to minimize recurrence and detect clinically unapparent disease.

Advancement flap repair: a good option for complex anorectal fistulas

BACKGROUND

Rectal advancement flap is a popular option for treatment of complex anal fistula. Although early outcomes vary, concerns remain about postoperative continence, long-term healing, and its role in patients with Crohn's disease and anovaginal fistulas.

PURPOSE

This study aimed to report long-term outcomes in patients with complex fistula disease.

PATIENTS

Patients who were undergoing rectal advancement flap for anal fistula were included in the study.

DESIGN

Patients were contacted to determine the status of their fistula disease, their bowel function, and their degree of fecal incontinence.

MAIN OUTCOME MEASURES

The main outcomes measured were healing rate and continence.

RESULTS

There were 98 patients, 43 men and 55 women, mean age 53 ± 14 years. Fifty-eight had cryptoglandular fistulas, and 40 (41%) had IBD (33 had Crohn's disease). Seventy-seven of 98 patients had perianal fistulas, and all 77 underwent seton drainage before advancement flap. Twenty-one women had anovaginal fistulas. Average postoperative length of stay was 3 ± 1 days. There were no mortalities. Follow-up was possible in 75 patients, a mean of 7 ± 3 years after surgery. Primary healing occurred in 54 (72%) patients. Twenty-one patients (28%) underwent further treatment, and 12 (57%) healed after a second advancement flap. Four more patients healed after more than 2 flaps or fistulotomy leading to an overall healing rate of 70 of 75 (93%). Patients with Crohn's disease had lower healing rates than those with cryptoglandular fistulas (87% vs 98%). Thirty-two patients (43%) had normal fecal continence before flap, and 43 (57%) had normal fecal continence after flap.

CONCLUSION

Advancement flap is a good option for patients with complex anal fistulas.

Anatomic characteristics of anal fistula on three-dimensional anorectal ultrasonography

BACKGROUND

Surgery for anal fistula is often associated with continence disorders due to the transection of sphincter muscles. Extensive knowledge of anal canal anatomy and anal fistula can help prevent this outcome.

OBJECTIVE

This study aimed to correlate the anatomical conformation of the anal canal, the fistula track, and the internal opening according to sex and hemicircumference (anterior vs posterior) by use of 3-dimensional ultrasonography.

METHODS

One hundred sixty-five patients with fistula were evaluated with 3-dimensional ultrasound and grouped according to sex, fistula type, internal opening, and track position. Fistulas were transsphincteric in 128 subjects and intersphincteric in 37 subjects. The study measured the external and internal anal sphincter, the puborectalis, the distance from the internal opening to the distal edge of the external and internal sphincter, the length of the internal and external sphincter compromised by the track, and the percentage of compromised muscle.

RESULTS

The anal canal muscles were longer in males. The distance from the internal opening to the internal sphincter was greater for the posterior hemicircumference. The point where the fistulous track crossed the anterior external sphincter was similar for the 2 sexes, but the percentage of compromised muscle was greater in females. The point where the fistulous track crossed the internal sphincter was similar for the 2 sexes, but the percentage of compromised internal sphincter was greater in males for the posterior hemicircumference. The study was limited by the absence of testing for interobserver and intraobserver agreement.

CONCLUSION

The anal canal muscles are longer in males and the pectinate line is asymmetrical. In females, the percentage of compromised external sphincter was greater in the anterior hemicircumference because of the shorter external sphincter, whereas in males the percentage of compromised internal sphincter was greater in the posterior hemicircumference.

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.

Role of magnetic resonance imaging in evaluation of the activity of perianal Crohn's disease

AIM

To evaluate the diagnostic ability of contrast-enhanced Magnetic Resonance Imaging (MRI) in assessment of the activity of perianal fistulas in Crohn's disease (CD) patients, compared to clinical data.

MATERIALS AND METHODS

Fifty CD patients (25 men; mean[SD] age: 40.4[12.6] years) with known or suspected perianal fistulas underwent perianal space MRI. Radiological activity of disease was measured as the percentage increase (PI) of ROI values of fistulas in relation to ROI values of healthy local fat, after contrast administration. Clinical activity of disease was defined according to Perianal Disease Activity Index (PDAI) and Fistula Drainage Assessment (FDA).

RESULTS

Forty-two patients presented perianal disease at MRI (55 fistulas identified). An association between both fistula's PI and PDAI (Pearson's coefficient 0.512, p<0.0001) and between PI and FDA (p=0.003) was demonstrated. Areas under ROC curves of PI values in relation to PDAI and FDA were respectively 0.876 [95%CI=(0.743-1.00), p<0.001] and 0.784 [95%CI=(0.588-0.980), p=0.003]. A cut-off value of PI, calculated on these preliminary data, correctly classified more than 90% of fistulas.

CONCLUSIONS

Contrast-enhanced MRI with PI calculation offered practical information about activity of perianal fistulas and might be helpful in providing a comprehensive evaluation of CD perianal disease.