Anovaginal Fistulas: Evaluation with Endoanal MR Imaging

Current update on the role of endoanal ultrasound: a primer for radiologists

Endoanal ultrasound (EAUS) is a valuable imaging modality for the evaluation of anal and perianal pathologies. It provides detailed information about the anatomy and physiology of the anorectal region and has been used in pre-and post-operative settings of anorectal pathologies. EAUS is not only useful in the evaluation of benign pathologies but also in loco-regional staging of anal and rectal tumors. EAUS has several advantages over MRI, including reduced cost, better patient tolerance, and improved scope of application in patients with contraindications to MRI. Despite its benefits, EAUS is not widely performed in many centers across the globe. This article aims to educate radiologists, trainees, and surgeons about the indications, contraindications, patient preparation, imaging technique, and findings of EAUS. We will also highlight the technical difficulties, diagnostic challenges, and procedural complications encountered during EAUS, along with a comparative analysis of EAUS with other imaging approaches.

MRI of the ileal pouch

Ileal pouch surgery is the surgical gold standard treatment for patients with ulcerative colitis (UC) and familial adenomatous polyposis (FAP). However, ileal pouch surgery is a technically challenging procedure and is associated with high morbidity. Clinical presentations of pouch complications are often nonspecific but imaging can identify many of these complications and is essential in clinical management. This paper will focus on magnetic resonance imaging (MRI) of the ileal pouch, including recommended MRI protocol and approach to imaging interpretation with an emphasis on those ileal pouch complications particularly well evaluated with MRI.

[Perianal Fistula: An Overview]

Perianal fistula is a common inflammatory condition in the general population and affects the area around the anal canal. Although most cases are benign, they cause serious morbidity and require surgical treatment due to a high risk of recurrence. MR imaging is a gold standard technique for the evaluation of perianal fistulas and provides accurate information on the anatomy of the anal canal, its relationship to the anal sphincter complex, accurate identification of secondary tracts or abscesses, and reporting associated complications. MR imaging can help monitor treatment effects and determine treatment methods. Crohn's disease-related fistulas often require medical rather than surgical treatment. The radiologist is required to know the anatomy and MR imaging findings of the perianal fistula to present an accurate diagnosis to the clinician.

Vesicovaginal fistula with bladder and vaginal stone

INTRODUCTION

In developing countries, Vesico-vaginal fistula (VVF) results following obstetric trauma or iatrogenic during hysterectomy. Large calculus associated with VVF is relatively rare, with the risk factor are presence of foreign body, urinary tract infection, and prolonged duration of disease. Most bladder stones can be found among patients who are bedridden, indwelling urethral catheter, bladder outlet obstruction, infection, and other similar characteristic. We report a case of VVF with bladder and vaginal stone in 37 years old woman and reviews the evaluation and treatment and highlights the role of the healthcare team in managing patients with this condition.

PRESENTATION OF CASE

A 37-year-old, P2A0, woman with a history of hysterectomy three years ago. Intermittent small amounts of watery vaginal discharge developed 1,5 years after the operation. A physical examination revealed mild tenderness over the suprapubic area and no evidence of uterine prolapse. Cystography computed tomography scan with contrast confirmed a fistula vesicovagina with a connection between posterosuperior wall of vesica urinaria and anterosuperior wall of vagina with vesicolithiasis, size 15 × 26 × 14 mm and two vaginal stone with size of 7 × 12 × 17 mm and 4 × 4 × 5 mm. Cystoscopy revealed a grayish stone identified in supratrigone with size of 30 × 12 mm.

DISCUSSION

A hanging intravesical stone on the dome of urinary bladder is scarce, possibly caused by any synthetic and non-absorbable suture material inside of the bladder were encrusted forming a bladder stone. Important risk factors known, which is specific in developing countries, are poor socioeconomic status, malnourishment, low literacy rate, early marriage and childbearing, and inadequate obstetrical care.

CONCLUSION

Although the incidence of VVF accompanied by hanging vaginal stone and a large bladder stone is scarce, reports of any case regarding this study can be beneficial to other studies. Due to its harmful effect, the usage of non-absorbable sutures material during surgery isn't suggested. Hence, the absorbable suture material usage with careful dissection is suggested for any gynecological or pelvic surgery.

Female Pelvic Fistulae

Female pelvic fistulae are a pathologic connection between the urinary or gastrointestinal tract and the genital tract. Although this condition has been present for millennia, successful surgical treatments have only been described for the past few hundred years. In developed nations, the most common cause of genitourinary fistulae is benign gynecologic surgery, but worldwide it is obstetric trauma. Fistulae management is rooted in surgical intervention with the highest probability of success associated with the first repair.

Recto-vaginal fistulas: A case series

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Falandry and Martius’ techniques were used firstly for vesico-vaginal fistulas with satisfying long-term functional results.

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The same techniques are feasible and safe for rectovaginal fistula repair.

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In this case series, patients had an improvement of their self-image and health-related quality of life.

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Temporary colostomy is recommended before this reconstructive surgery.

Introduction

Rectovaginal fistula (RVF) is defined as an abnormal communication between the anterior wall of the rectum and the posterior wall of the vagina. Many surgical techniques have been described in the treatment of RVF. However, none has proved its superiority. The aim of the study was to evaluate the functional results of surgical treatment of RVF using Martius and Falandry techniques in order to assess the feasibility and the efficacy of these techniques which were first described for vesico-vaginal fistulas.

Methods

The study was a retrospective case series conducted in a single centre: Department of general surgery at Ibn Sina University Hospital in Rabat. We included patients with rectovaginal fistula consecutively recruited from 2011 to 2014. 10 patients developed RVF after surgery for rectal cancer (9 cases), uterine cancer (1 case). One patient had RVF for ano-rectal malformation. Colostomy was performed before the treatment of fistula in 9 cases (82 %). They underwent surgical treatment using Falandry (8 patients) and Martius techniques (3 patients) performed by an experienced urologist surgeon.

Results

No postoperative complications were recorded. Time to discharge was postoperative day 3–4. There was a complete disappearance of RVF in 8 patients (72.7 % of cases), relapse in 2 cases (18 %), and failure in one case (9%). The average follow-up was 12.6 +/-10 months. Functionally, no long-term cases of fecal incontinence or dyspareunia were noted.

Conclusion

The choice of surgical technique in the treatment of RVF remains difficult because of poor literature data and absence of consensus. RVF repair results either by Martius or Falandry techniques are encouraging with low morbidity.

Use of the Martius advancement flap for low rectovaginal fistulas

AIM

The percentage recurrence after any surgical treatment for low rectovaginal fistula (LRVF) is unacceptably high. The aim of this study was to evaluate the short- and long-term results of the Martius procedure in a carefully selected series of patients with a LRVF of at least 1 cm diameter who had had at least two previous surgeries or in the presence of chronically inflamed local tissues.

METHOD

Between January 2009 and April 2017, 24 patients with the abovementioned features were prospectively included in this study. Success was defined both as the absence of any subjective symptoms and the fistula, as confirmed by evaluation under anaesthesia. Postoperative complications were assessed using the Clavien-Dindo classification. Quality of life (SF-12 score), quality of sexual life [Female Sexual Function Index (FSFI) score] and continence [Cleveland Clinic Incontinence Score (CCIS)] were also determined pre- and postoperatively.

RESULTS

The mean follow-up was 42 ± 29 months (range 3-101 months). The overall success rate was 91.3% (22/24 patients). The median operation time was 50 min (range 45-70 min), and the median hospital stay was 3.5 days (range 3-5 days). No major complications occurred. Pre- and postoperative CCIS did not differ [1 (range 0-3.5)]. The postoperative SF-12 score improved both in terms of the physical (33.6 ± 7.2 vs 50.8 ± 7.8; P < 0.001) and mental (32.6 ± 6.7 vs 56.3 ± 7.8; P < 0.001) components. FSFI improved from 19.5 ± 6.6 to 24.4 ± 6.3 (P < 0.001).

CONCLUSION

The Martius procedure should be considered as the first-line method of treatment in carefully selected cases of LRVF.

MRI anatomy and pathology of the anal canal

The normal function of the anal sphincter complex is crucial for quality of life, as it is the mechanism by which fecal continence is maintained. Additionally, the anal sphincter complex is an integral part of the coordinated effort of defecation. As imaging plays an important role in assessment of pathologic conditions involving the anal region, understanding the normal anatomy of the anal sphincter complex is important for correct image interpretation and accurate diagnosis. This review discusses the anatomy and function of the anal sphincter complex, important technical considerations for MRI, and various inflammatory, infectious, and neoplastic processes, as well as pathologic structural conditions that affect the anal region. Level of Evidence: 5 Technical Efficacy Stage: 3 J. Magn. Reson. Imaging 2019;50:1018-1032.

MRI evaluation of anal and perianal diseases

Anal and perianal region is a commonly affected area in the course of several inflammatory, infectious, and neoplastic diseases. Several imaging modalities may be used in imaging evaluation of this area and magnetic resonance imaging (MRI) emerges as the imaging modality of choice due to its superb soft tissue resolution. MRI is not only useful for initial detection of anal/perianal pathologies but also in the follow-up of these disorders. In this article, we aimed to illustrate MRI findings of several diseases affecting this area including perianal fistula as well as anal fissure, hypertrophic myopathy of internal anal sphincter, hidradenitis suppurativa, pilonidal sinus, rectovaginal/anovaginal fistula and anal canal carcinoma. We think that this article will serve to familiarize the imaging specialists to the MRI findings of these diseases.

The Association of Coloproctology of Great Britain and Ireland consensus guidelines in surgery for inflammatory bowel disease

AIM

There is a requirement of an expansive and up to date review of surgical management of inflammatory bowel disease (IBD) that can dovetail with the medical guidelines produced by the British Society of Gastroenterology.

METHODS

Surgeons who are members of the ACPGBI with a recognised interest in IBD were invited to contribute various sections of the guidelines. They were directed to produce a procedure based document using literature searches that were systematic, comprehensible, transparent and reproducible. Levels of evidence were graded. An editorial board was convened to ensure consistency of style, presentation and quality. Each author was asked to provide a set of recommendations which were evidence based and unambiguous. These recommendations were submitted to the whole guideline group and scored. They were then refined and submitted to a second vote. Only those that achieved >80% consensus at level 5 (strongly agree) or level 4 (agree) after 2 votes were included in the guidelines.

RESULTS

All aspects of surgical care for IBD have been included along with 157 recommendations for management.

CONCLUSION

These guidelines provide an up to date and evidence based summary of the current surgical knowledge in the management of IBD and will serve as a useful practical text for clinicians performing this type of surgery.

MR Imaging of Perianal Fistulas

In this article, we begin with an introduction of the perianal region anatomy, then review the definition, etiology, epidemiology, and 2 major classification systems of perianal fistulas. The role of MR imaging for assessment of perianal fistulas is mainly discussed. Finally, the medical and surgical treatment principles are reviewed.

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.

MRI of anal canal: normal anatomy, imaging protocol, and perianal fistulas: Part 1

Anal complaints are very common in the general population and are caused by a variety of disorders mostly benign in nature. The aim of this article is to provide the radiologist with a detailed description of the MRI anatomy and technique, and an overview of the various diseases most commonly presenting with anal pain, by descriptions and illustrative examples of MRI features of each entity.

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

Perianal fistulas are a major problem in many patients with Crohn's disease. These are usually complex fistulas that adversely affect patients' quality of life, and their clinical management is difficult. Medical treatment sometimes achieves cessation of discharge and closure of the external opening; however, it is difficult to assess the status of the rest of the fistula tract. Magnetic resonance imaging is the method of choice with which to evaluate the condition of perianal fistulas and allows for assessment of the status of inaccessible areas. Magnetic resonance imaging also allows the clinician to evaluate other perianal manifestations of Crohn's disease that differ from the fistulas. This imaging technique is therefore a fundamental means of patient monitoring. When used in conjunction with assessment of the patient's morphological findings, it provides information that allows for both quantification of disease severity and evaluation of the response to treatment. New types of magnetic resonance sequences are emerging, such as diffusion, perfusion, and magnetisation transfer. These sequences may serve as biomarkers because they provide information reflecting the changes taking place at the molecular level. This will help to shape a new scenario in the early assessment of the response to treatments such as anti-tumour necrosis factor drugs.

TEACHING POINTS

• MRI is the method of choice with which to evaluate perianal fistulas. • In perianal Crohn's disease, MRI is a fundamental means of patient monitoring. • The usefulness of the Van Assche score for patient monitoring remains unclear. • New MRI sequences' diffusion, perfusion, and magnetisation transfer may serve as biomarkers.

MR Imaging of Perianal Crohn Disease

Pelvic magnetic resonance (MR) imaging is currently the standard for imaging perianal Crohn disease. Perianal fistulas are a leading cause of patient morbidity because closure often requires multimodality treatments over a prolonged period of time. This review summarizes clinically relevant anal sphincter anatomy, imaging methods, classification systems, and treatment objectives. In addition, the MR appearance of healing perianal fistulas and fistula complications is described. Difficult imaging tasks including the assessment of rectovaginal fistulas and ileoanal anastomoses are highlighted, along with illustrative cases. Emerging innovative treatments for perianal Crohn disease are now available and have the promise to better control sepsis and maintain fecal continence. Different treatment modalities are selected based on fistula anatomy, patient factors, and management goals (closure versus sepsis control). Radiologists can help maximize patient care by being familiar with MR imaging features of perianal Crohn disease and knowledgeable about what features may influence therapy decisions. ^© RSNA, 2017 Online supplemental material is available for this article.

Management of Complex Perineal Fistula Disease

Management of complex perineal fistulas such as high perianal, rectovaginal, pouch-vaginal, rectourethral, or pouch-urethral fistulas requires a systematic approach. The first step is to control any sepsis with drainage of abscess and/or seton placement. Patients with large, recurrent, irradiated fistulas benefit from stoma diversion. In patients with Crohn's disease, it is essential to induce remission prior to any repair. There are different approaches to repair complex fistulas, from local repairs to transperineal and transabdominal approaches. Simpler fistulas are amenable to local repair. More complex fistulas, such as those secondary to irradiation, require interposition of healthy, well-vascularized tissue. The most common flap used for this treatment is the gracilis muscle with good outcomes reported. Once healing is confirmed by imaging and endoscopy, the stoma is reversed.

Clinical value of endoluminal ultrasonography in the diagnosis of rectovaginal fistula

Background

Rectovaginal fistula (RVF) refers to a pathological passage between the rectum and vagina, which is a public health challenge. This study was aimed to explore the clinical value of endoluminal biplane ultrasonography in the diagnosis of rectovaginal fistula (RVF).

Methods

Thirty inpatients and outpatients with suspected RVF from January 2006 to June 2013 were included in the study, among whom 28 underwent surgical repair. All 28 patients underwent preoperative endoluminal ultrasonography, and the obtained diagnostic results were compared with the corresponding surgical results.

Results

All of the internal openings located at the anal canal and rectum of the 28 patients and confirmed during surgery were revealed by preoperative endosonography, which showed a positive predictive value of 100 %. Regarding the 30 internal openings located in the vagina during surgery, the positive predictive value of preoperative endosonography was 93 %. The six cases of simple fistulas confirmed during surgery were revealed by endosonography; for the 22 cases of complex fistula confirmed during surgery, the positive predictive value of endosonography was 90 %. Surgery confirmed 14 cases of anal fistula and 14 cases of RVF, whereas preoperative endoluminal ultrasonography suggested 16 cases of anal fistula and 12 cases of RVF, resulting in positive predictive values of 92.3 and 93 %, respectively.

Conclusion

The use of endoluminal biplane ultrasonography in the diagnosis of RVF can accurately determine the internal openings in the rectum or vagina and can relatively accurately identify concomitant branches and abscesses located in the rectovaginal septum. Thus, it is a good imaging tool for examining internal and external anal sphincter injuries and provides useful information for preoperative preparation and postoperative evaluation.

Rectovaginal Fistulae

Rectovaginal fistulae are abnormal epithelialized connections between the rectum and vagina. Fistulae from the anorectal region to the posterior vagina are truly best characterized as anovaginal or very low rectovaginal fistulae. True rectovaginal fistulae are less common and result from inflammatory bowel disease, trauma, or iatrogenic injury. A very few patients are asymptomatic, but the symptoms of rectovaginal fistula are incredibly distressing and unacceptable. Diagnostic approach, timing, and choice of surgical intervention, including sphincteroplasty, gracilis flaps, Martius flaps, and special circumstances are discussed.

Chronic anal and perianal pain resolved with MRI

OBJECTIVE

The purpose of this study was to assess the diagnostic value of anorectal MRI in the care of patients with chronic anal and perianal pain but without findings of abnormalities in the clinical workup.

MATERIALS AND METHODS

Patients referred from a tertiary department of colorectal surgery to the MRI unit with clinically occult chronic anal and perianal pain were included. MRI of the anorectum was performed with an endoanal or pelvic phased-array coil. The images from all examinations were read by two radiologists. MRI findings were correlated with clinical follow-up data.

RESULTS

The study group (103 patients) was stratified into patients with no history of anorectal disease (n = 60) and those who had a history of surgery for anorectal disease (n = 43). MRI findings suggested the final diagnoses in 40 patients (39%). These diagnoses were 28 cases of suppurative lesions (27%), 11 cases of painful scarring of the anus (11%), and one case of metastasis to the sacrum (1%). Suppurative lesions were surgically proved with marked relief of pain after surgery. In the other patients the final diagnoses were 37 cases of levator ani syndrome (36%) and 26 cases of unspecified functional anorectal pain (25%). No MRI abnormalities were found in 33 of the patients with levator ani syndrome and 26 of the patients with unspecified anorectal pain. The two readers had very good agreement (κ = 0.92). The patients with a history of anorectal disease had significantly more MRI findings of abnormalities (60%) than did patients without a history of anorectal disease (23%). The positive predictive value of MRI was 91%, and the negative predictive value was 100%.

CONCLUSION

In 39% of patients, MRI showed abnormalities that were clinically confirmed as the final diagnosis. Surgical treatment will especially benefit patients with suppurative lesions, resulting in relief of pain.

Crohn disease and the gynecologic patient

Although Crohn disease (CD) is considered an inflammatory bowel disease, extraintestinal gynecologic manifestations are varied, frequent, and oftentimes difficult to manage. Its predilection for young and reproductive-age women makes it an important disease process for the gynecologist to understand, as its complications can have long-term repercussions on the developmental, sexual, reproductive, and psychological health of affected women. Patients may present with a variety of vulvovaginal, perineal, perianal, and urologic complaints. Perianal involvement from an intestinal fistula is the most common skin manifestation seen in CD. Other gynecologic manifestations include metastatic CD and rectovaginal and urovaginal fistulas. Recognition and accurate diagnosis of extraintestinal gynecologic manifestations, as well as a good understanding of the gynecologic effects of chronic disease, are necessary for optimal management. The article provides an overview of CD and highlights the gynecologic considerations in caring for women affected by this disease.

Vesicovaginal fistula: diagnosis and management

Vesicovaginal fistula (VVF) is still a major cause for concern in many developing countries. It represents a significant morbidity in female urology. Continual wetness, odor, and discomfort cause serious social problems. The diagnosis of the condition has traditionally been based on clinical methods and dye testing. A successful repair of such fistulas requires an accurate diagnostic evaluation and timely repair using procedures that exploit basic surgical principles and the application of interposition flaps. The method of closure depends on the surgeon's training and experience. The main complication of VVF surgery is recurrent fistula formation.

Contrast-enhanced ultrasonography (CEUS) vs. MRI of the small bowel in the evaluation of Crohn's disease activity

PURPOSE

The presence of disease activity in Crohn's disease (CD) is one of the main parameters used to establish whether optimal therapy should be drug therapy or surgery. However, a major problem in monitoring CD is the common mismatch between the patient's symptoms and imaging objective signs of disease activity. Bowel ultrasonography (US) has emerged as a low-cost, noninvasive technique in the diagnosis and follow-up of patients with CD. Accordingly, the use of contrast-enhanced US (CEUS) has made possible an evaluation of the vascular enhancement pattern, similar to the use of magnetic resonance imaging (MRI). The aim of our study was to evaluate the role of CEUS in comparison with small-bowel MRI for assessing Crohn's disease activity.

MATERIALS AND METHODS

We prospectively enrolled 30 consecutive patients with known CD. Clinical and laboratory data were compared with imaging findings obtained from MRI and CEUS of the small bowel. MRI was performed with a 1.5-T system using phased-array coils and biphasic orally administered contrast agent prior to and after gadolinium chelate administration. We performed US with a 7.5-MHz linear-array probe and a second-generation contrast agent. The parameters analysed in both techniques were the following: lesion length, wall thickness, layered wall appearance, comb sign, fibroadipose proliferation, presence of enlarged lymph nodes and stenosis. We classified parietal enhancement curves into two types in relation to the contrast pattern obtained with the time-intensity curves at MRI and CEUS: (1) quick washin, quick washout, (2) slow washin, plateau with a slow washout.

RESULTS

Comparison between Crohn's disease activity index (CDAI) and MRI showed a low correlation, with an rho=0.398; correlation between CDAI-laboratory data and CEUS activity was low, with rho=0.354; correlation between MRI activity and CEUS activity was good, with rho = 0.791; high correlation was found between CEUS and MRI of the small bowel when assessing wall-thickness, lymph nodes and comb sign; good correlation was fund when assessing layered wall appearance, disease extension and fibroadipose proliferation. At MRI, time-intensity curves for 12/30 patients were active, compared with for 14/30 patients at CEUS; therefore there was a poor correlation between curve on CEUS and curve on MRI (r=0.167; p=0.36).

CONCLUSIONS

The use of CEUS can be recommended if there is a discrepancy between MRI and clinical/laboratory parameters. MRI of the small bowel remains the most accurate method for evaluating disease activity.

Magnetic resonance imaging in the management of anal fistula and anorectal sepsis

Complex perianal disease may be extremely debilitating for the patient with significant impingement on quality of life. The accurate identification of anatomical areas of involvement and subsequent appropriate management is crucial to achieving a successful outcome when treating anorectal sepsis and anal fistulae. Magnetic resonance imaging (MRI) has become a powerful tool in the evaluation of anal anatomy. In patients with complex disease MRI is an important adjunct in delineating disease location and extent, its relationship to sphincter muscles, and in planning management. MRI also plays an important role in evaluating the response to medical and surgical therapies.

Rectovaginal fistula

Despite the prevalence and severe implications of rectovaginal fistula, there is no universally accepted evidence-based approach to surgical management. This article offers a disease-based review of traditional management strategies and highlights the variety of technical approaches that are currently effective for the eradication of this socially disabling condition.

Current considerations in the management of rectovaginal fistula from Crohn's disease

Rectovaginal fistulas are dreaded complications of Crohn's disease. Accurate assessment is essential for planning management. Treatment options range from observation to medical therapeutics to the need for surgical intervention. Ultimately, establishing reasonable expectations is mandatory when treatment algorithms are considered. In this article, we review the evaluation of these fistulas and the current options to consider in the treatment of Crohn's related rectovaginal fistula.

Magnetic resonance fistulography for the demonstration of anovaginal fistula: an alternative imaging technique?

Anovaginal fistulae (AVF) are frequently seen in patients with inflammatory bowel disease, especially in Crohn disease with active colonic inflammation. Herein, we report a 21-year-old woman with Crohn disease suffering from vaginal discharge and anal pain. Although clinical presentation was very suggestive of AVF, physical examination and colonoscopy were inconclusive. We used an alternative technique and performed magnetic resonance fistulography by applying rectal contrast for the demonstration of AVF.

Evaluating bowel wall vascularity in Crohn’s disease: a comparison of dynamic MRI and wideband harmonic imaging contrast-enhanced low MI ultrasound

This was a prospective comparison of dynamic MRI (1.5 T) and echo-signal enhanced ultrasound in evaluating vascularization in thickened bowel walls cases of Crohn's disease. Twenty-one patients with histologically confirmed Crohn's disease and bowel wall diameters >5 mm were examined by MRI and ultrasound (US). MR sequences: T1w fl2D, T2w, FLASH T1w post-contrast media (CM) applications with fat saturation were used. Dynamic Turbo-FLASH T1w sequences were acquired in the area of maximal thickening of the ileal wall every 1.5 s post-CM application for a total duration of 1 min. US was performed after the application of 1.2 ml of echo-signal enhancer. Contrast uptake was measured by the semiquantitative score and brightness analysis in regions of interest (ROI). Clinical and laboratory findings including Crohn's disease activity indices were documented; MRI and US parameters were correlated. The length of sonographically documented lesions (122+/-75 mm) correlated significantly with the length of thickened bowel segments in MRI (128+/-76 mm; r=0.466; P=0.033). The maximum percent signal enhancement in the terminal ileum at ultrasound (217.5+/-100.1%) showed a high correlation with the findings of MRI (262+/-108%; r=0.623; P=0.003). With both methods, a plateau phase was observed. US and MRI are capable of evaluating local vascularization in the bowel wall objectively.

Magnetic resonance imaging of perianal fistulas

Most cases of fistula-in-ano are nonspecific and result from inflammation of anal glands and crypts (cryptoglandular). The classification of cryptoglandular fistulas depends on the degree of involvement of the anal sphincter complex and determines the type of treatment. Studies have shown that preoperative MR imaging revealed important additional information compared with surgery alone and better predicts clinical outcome of patients with fistula-in-ano than initial surgical exploration. With the emergence of novel surgical treatments like MRI-guided surgery, laser, and adhesive treatments, MR imaging is a mainstay for preprocedural and intraoperative evaluation to ensure the adequacy of the procedure.