In Japan, the confirmed diagnosis of Crohn's disease (CD) is based on a single, historically established set of clinical criteria. However, for patients who present with a perianal lesion (PL), the diagnostic pattern actually applied is unclear.

We conducted a retrospective observational multicenter study among patients who presented with a PL without synchronous abdominal symptoms and were subsequently diagnosed with confirmed or probable CD according to the Japanese diagnostic criteria from May 1996 to April 2024. In total, 100 patients with confirmed CD and 10 with probable CD were identified and enrolled.

Among the 100 patients with confirmed CD, 72% met the criterion for the category "confirmed 1: main finding A (longitudinal ulcer) or B (cobblestone appearance)." In the same cohort, 35% met the criterion for the category "confirmed 2: main finding C (non-caseating epithelioid cell granuloma [NCEG]) with secondary finding a (extensive irregular-to-round ulcers or aphthae in the gastrointestinal tract) or b (characteristic anorectal lesions)," including 24% without the main finding A or B. Finally, 4% met the criterion for the category "confirmed 3: all secondary findings a, b, and c (characteristic gastric and duodenal lesions)." All 10 patients with probable CD were diagnosed based on secondary finding b only or secondary findings a and b.

In cases of suspected CD due to initial PLs, histological investigation of NCEG and precise total gastrointestinal inspection should be conducted to confirm the diagnosis.

A singular reliable modality for early distinguishing perianal fistulizing Crohn's disease (PFCD) from cryptoglandular fistula (CGF) is currently lacking. We aimed to develop and validate an MRI-based deep learning classifier to effectively discriminate between them.

The present study retrospectively enrolled 1054 patients with PFCD or CGF from three Chinese tertiary referral hospitals between January 1, 2015, and December 31, 2021. The patients were divided into four cohorts: training cohort (n = 800), validation cohort (n = 100), internal test cohort (n = 100) and external test cohort (n = 54). Two deep convolutional neural networks (DCNN), namely MobileNetV2 and ResNet50, were respectively trained using the transfer learning strategy on a dataset consisting of 44871 MR images. The performance of the DCNN models was compared to that of radiologists using various metrics, including receiver operating characteristic curve (ROC) analysis, accuracy, sensitivity, and specificity. Delong testing was employed for comparing the area under curves (AUCs). Univariate and multivariate analyses were conducted to explore potential factors associated with classifier performance.

A total of 532 PFCD and 522 CGF patients were included. Both pre-trained DCNN classifiers achieved encouraging performances in the internal test cohort (MobileNetV2 AUC: 0.962, 95% CI 0.903-0.990; ResNet50 AUC: 0.963, 95% CI 0.905-0.990), as well as external test cohort (MobileNetV2 AUC: 0.885, 95% CI 0.769-0.956; ResNet50 AUC: 0.874, 95% CI 0.756-0.949). They had greater AUCs than the radiologists (all p ≤ 0.001), while had comparable AUCs to each other (p = 0.83 and p = 0.60 in the two test cohorts). None of the potential characteristics had a significant impact on the performance of pre-trained MobileNetV2 classifier in etiologic diagnosis. Previous fistula surgery influenced the performance of the pre-trained ResNet50 classifier in the internal test cohort (OR 0.157, 95% CI 0.025-0.997, p = 0.05).

The developed DCNN classifiers exhibited superior robustness in distinguishing PFCD from CGF compared to artificial visual assessment, showing their potential for assisting in early detection of PFCD. Our findings highlight the promising generalized performance of MobileNetV2 over ResNet50, rendering it suitable for deployment on mobile terminals.

National Natural Science Foundation of China.

Isolated complex perianal fistulas, without luminal evidence of inflammatory bowel disease in the gastrointestinal tract, pose diagnostic and treatment dilemmas for gastroenterologists and colorectal surgeons. For patients who develop recurrent complex fistulas, a presumptive diagnosis of Crohn's disease may be made. It is unclear whether these cases of isolated perianal disease in the absence of luminal inflammation truly represent isolated severe cryptoglandular fistulas or rather an early presentation of Crohn's disease. We aimed to investigate the clinical course and outcomes of patients with isolated complex perianal fistulas.

In this retrospective multicenter case series across 6 institutions in the United States, we report the clinical course of patients with isolated recurrent complex perianal fistulas, including their diagnostic evaluation, medical and surgical therapies, and clinical outcomes.

All patients (n = 24) required incision and drainage of perirectal abscesses. The majority received setons (n = 19, 79%), more intensive surgical interventions (n = 15, 62.5%, including fistulotomy/sphincterotomy, advancement flap, and ligation of the intersphincteric fistula tract), antibiotics (n = 17, 71%), and biologic therapy (n = 16, 67%). Nine patients (37.5%) underwent a combined medical-surgical approach with biologics and intensive surgical intervention. Despite surgical and/or medical management, active symptomatic complex perianal fistulas persisted in 58% (n = 14) of patients at follow-up (median 5.5 years, interquartile range 2.5-10 years); symptom remission was achieved in 21% (n = 5), and fistula closure in 21% (n = 5).

These cases highlight a multidisciplinary and multimodal approach when treating isolated complex perianal fistulas and their propensity to persist despite the incorporation of advanced therapies.

Complicated perianal disease (cPD) may be the sole presentation of Crohn's disease (CD). The role of small-bowel capsule endoscopy (SBCE) in the diagnostic algorithm of cPD is unclear. We aimed to evaluate the role of SBCE as a diagnostic tool, in patients with cPD, after a negative standard workup for CD.

A multicenter, retrospective, cross-sectional study, in patients with cPD, and negative standard workup for CD (ileocolonoscopy and cross-sectional imaging), who underwent SBCE for suspected CD. Demographics, biomarkers, and the Lewis Score (LS) were recorded and analyzed. An LS ≥ 135 was considered a positive SBCE for diagnosing CD.

Ninety-one patients were included: 65 (71.4%) males; median age: 37 (29-51) years; cPD duration: 25.1 (12.5-66.1) months. Positive SBCE: 24/91 (26.4%) patients. Fecal calprotectin (FC) positively correlated with LS (r = 0.81; p < 0.001). FC levels of 100 µg/g and 50 µg/g had a sensitivity of only 40% and 55% to rule out small-bowel CD, with a negative predictive value (NPV) of only 76% and 80%, respectively.

SBCE contributed to CD diagnosis in a quarter of patients with cPD after a negative standard workup. FC levels correlated with the degree of inflammation defined by the LS. However, the NPV of FC was low, suggesting that SBCE should be considered for patients with cPD even after a negative standard workup.

Accurate tools to distinguish Crohn's disease [CD] from cryptoglandular disease in patients with perianal fistulas without detectable luminal inflammation on ileocolonoscopy and abdominal enterography (isolated perianal fistulas [IPF]) are lacking. We assessed the ability of video capsule endoscopy [VCE] to detect luminal inflammation in patients with IPF.

We studied consecutive adults [>17 years] with IPF who were evaluated by VCE after a negative ileocolonoscopy and abdominal enterography between 2013 and 2022. We defined luminal CD by VCE as diffuse erythema, three or more aphthous ulcers, or a Lewis score greater than 135. We compared rates of intestinal inflammation in this cohort with age- and sex-matched controls without perianal fistulas, who underwent VCE for other indications. We excluded persons with pre-existing inflammatory bowel disease [IBD] and exposure to non-steroidal anti-inflammatory drugs or immunosuppressive treatments.

A total of 45 patients with IPF underwent VCE without complications. Twelve patients [26%] met our definition of luminal CD. Luminal CD was more common in patients with IPF than in controls [26% vs 3%; p <0.01]. Among patients with IPF, male sex (OR [odds ratio], 9.2; 95% confidence interval [CI] [1.1-79.4]), smoking (OR, 4.5; 95% CI [0.9-21.2]), abscess (OR, 6.3; 95% CI [1.5-26.8]), rectal enhancement on magnetic resonance imaging [MRI] (OR, 9.0; 95% CI [0.8-99.3]), and positive antimicrobial serology (OR, 7.1; 95% CI, [0.7-70.0]) were more common in those with a positive VCE study.

VCE detected small intestinal inflammation suggestive of luminal CD in approximately one-quarter of patients with IPF. Larger studies are required to validate these findings.

Crohn's disease (CD) is a chronic inflammatory disease that develops at a young age and frequently leads to intestinal resection. Capsule endoscopy (CE) can directly and non-invasively inspect the entire small bowel mucosa. We suspected that CE could be a good diagnostic tool for detecting CD in young patients. The aim of this study was to investigate the safety and efficacy of CE in patients with newly diagnosed CD and to evaluate the CE findings, especially in the upper small bowel of young patients. We retrospectively investigated 32 patients with newly diagnosed CD from 5 institutions. Patient characteristics, clinical course, and characteristics of CE findings were analyzed. The total small intestine observation rate was 93%, and the retention rate was 3% (1/32). No abnormality was identified by ileocolonoscopy in 46% (15/32), and transition of small bowel lesions (TSL) was found in 35% (12/34) of the patients. The frequency of longitudinal ulcers and cobblestones in the upper small intestine was significantly higher in younger patients (≤20 years). Moreover, positive findings in the upper small intestine were predominantly observed in younger patients (≤20 years). CE for patients with newly diagnosed CD was safe and useful, especially for the detection of upper small bowel lesions in young patients.

Management of perianal fistulas differs based on fistula type. We aimed to assess the ability of diagnostic strategies to differentiate between Crohn's disease (CD) and cryptoglandular disease (CGD) in patients with perianal fistulas.

We performed a diagnostic accuracy systematic review and meta-analysis. A systematic search of electronic databases was performed from inception through February 2021 for studies assessing a diagnostic test's ability to distinguish fistula types. We calculated weighted summary estimates with 95% confidence intervals for sensitivity and specificity by bivariate analysis, using fixed effects models when data were available from 2 or more studies. The Quality Assessment of Diagnostic Accuracy Studies tool was used to assess study quality.

Twenty-one studies were identified and included clinical symptoms (2 studies; n=154), magnetic resonance imaging (MRI) characteristics (3 studies; n=296), ultrasound characteristics (7 studies; n=1003), video capsule endoscopy (2 studies; n=44), fecal calprotectin (1 study; n=56), and various biomarkers (8 studies; n=440). MRI and ultrasound characteristics had the most robust data. Rectal inflammation, multiple-branched fistula tracts, and abscesses on pelvic MRI and the Crohn's ultrasound fistula sign, fistula debris, and bifurcated fistulas on pelvic ultrasonography had high specificity (range, 80%-95% vs 89%-96%) but poor sensitivity (range, 17%-37% vs 31%-63%), respectively. Fourteen of 21 studies had risk of bias on at least 1 of the Quality Assessment of Diagnostic Accuracy Studies domains.

Limited high-quality evidence suggest that imaging characteristics may help discriminate CD from CGD in patients with perianal fistulas. Larger, prospective studies are needed to confirm these findings and to evaluate if combining multiple diagnostic tests can improve diagnostic sensitivity.

Capsule endoscopy (CE) has proven to be a valuable diagnostic modality for small bowel diseases over the past 20 years, particularly Crohn's disease (CD), which can affect the entire gastrointestinal tract from the mouth to the anus. CE is not only used for the diagnosis of patients with suspected small bowel CD, but can also be used to assess disease activity, treat-to-target, and postoperative recurrence in patients with established small bowel CD. As CE can detect even mildly non-specific small bowel lesions, a high diagnostic yield is not necessarily indicative of high diagnostic accuracy. Moreover, the cost effectiveness of CE as a third diagnostic test employed usually after ileocolonoscopy and MR or CT enterography is an important consideration. Recently, new developments in colon capsule endoscopy (CCE) have increased the utility of CE in patients with ulcerative colitis (UC) and pan-enteric CD. Although deflation of the colon during the examination and the inability to evaluate dysplasia-associated lesion or mass results in an inherent risk of overestimation or underestimation, the convenience of CCE examination and the risk of flare-up after colonoscopy suggest that CCE could be used more actively in patients with UC.

Perianal Crohn's disease (pCD) is a potentially severe phenotype of CD. We conducted a systematic review with meta-analysis to estimate cumulative incidence, risk factors, and outcomes of pCD in population-based cohort studies.

Through a systematic literature review through March 1, 2021, we identified population-based inception cohort studies reporting cumulative incidence of perianal disease (primarily abscess and/or fistula) in patients with CD. We estimated the cumulative incidence of pCD at presentation and 1-, 5-, and 10-year follow-up, and risk factors for perianal disease and outcomes including risk of major (bowel resection, proctectomy, ostomy) and minor perianal (incision and drainage, seton placement, etc.) surgery.

In 12 population-based studies, prevalence of pCD was 18.7% (95% confidence interval [CI], 12.5%-27.0%) with 1-, 5-, and 10-year risk of perianal disease being 14.3% (95% CI, 7.9%-24.6%), 17.6% (95% CI, 11.3%-26.5%), and 18.9% (95% CI, 15.0%-23.4%), respectively. Approximately 11.5% of patients (95% CI, 6.7%-19.0%) had perianal disease at or before CD diagnosis. Colonic disease location and rectal involvement were associated with higher risk of pCD. Overall, 63.3% of patients (95% CI, 53.3-72.3) required minor perianal surgery and 6.4% of patients (95% CI, 1.8%-20.6%) required major abdominal surgery for pCD. Use of biologic therapy for pCD is common and has steadily increased throughout the years.

Approximately 1 in 5 patients with CD develops perianal disease within 10 years of CD diagnosis, including 11.5% who have perianal disease at presentation. Approximately two-thirds of patients require perianal surgery, with a smaller fraction requiring major abdominal surgery.

Video capsule endoscopy is indicated in a broad range of clinical settings, most commonly in evaluating suspected small bowel bleeding. It is also useful in diagnosing Crohn's disease and monitoring patients with known Crohn's. Video capsule endoscopy has a role in evaluating patients with refractory celiac disease symptoms and in surveying patients with polyposis syndromes. The only absolute contraindication to video capsule endoscopy is luminal gastrointestinal tract obstruction. Despite manufacturer statement, video capsule endoscopy can be used safely in patients with implantable cardiac devices including pacemakers, defibrillators, and ventricular assist devices.

Most anal fistulas are crypto-glandular. Nevertheless, anal fistulas can reveal Crohn's disease (CD). The aim of our study was to evaluate the risk of developing CD in patients undergoing surgery for anal fistula.

All patients undergoing surgery for anal fistula in our center between January 1, 2008 and January 31, 2017 were identified through a prospective administrative database. Demographic, clinical, and laboratory data were retrospectively collected.

Ninety-three patients underwent anal exploration under general anesthesia. The median age at diagnosis of fistula was 43 years (IQR, 34-56) and 27% (n=29) were women. Twenty-seven percent (n=16) had had at least one previous fistula episode. After a median follow-up of 16.8 months (IQR, 7.2-42.0), seven (7.4%) patients were diagnosed with CD. The median time between the diagnosis of fistula and that of CD was 7.6 months (IQR, 2.7, 26.1). Chronic diarrhea (P=0.0003), weight loss (P=0.001), and chronic abdominal pain (P=0.002) were associated with the diagnosis of CD. Characteristics of the fistulas (number, simple/complex, abscess), smoking, extra-digestive manifestations of CD, or a family history of IBD were not associated with the diagnosis of CD.

A medical history of anal fistula surgery resulted in the diagnosis of CD in 7% of cases. Weight loss and the presence of digestive symptoms were associated with the diagnosis of CD. These elements could be used to select patients requiring endoscopic exploration after anal fistula.

Complex perianal fistulas occurring in the absence of luminal inflammation (isolated perianal disease, IPD) may represent a specific phenotype of Crohn's disease (CD).

We assessed the effectiveness of tumor necrosis factor (TNF)-antagonists in patients with IPD compared to those with perianal CD (PCD) with luminal inflammation.

Patients were identified through our institutional radiology database and were classified as PCD or IPD based on the presence or absence of luminal inflammation by ileocolonoscopy and abdominal enterography. Consecutive adults (> 17 years) with recurrent IPD who were treated with TNF antagonists were matched by age and gender to patients with complex PCD (1:2 ratio). Fistula remission was defined as an absence of fistula drainage. Surgery-free survival was assessed by Cox proportional hazard models.

Twenty-two patients with IPD treated with a TNF antagonist were compared with 44 matched patients with PCD. A similar proportion of patients with IPD and PCD were treated with concomitant immunomodulators (55% vs. 66%) and underwent examinations under anesthesia prior to therapy (36% vs. 46%). Fistula remission at 3, 6, and 12 months was lower for the IPD cohort: 9.5% versus 34%; 19% versus 39%; and 19% versus 43%. Surgical intervention after initiating anti-TNF therapy was more common for patients with IPD (HR 3.99: 95% CI, 1.62-9.83; p = 0.0026).

Fewer patients with IPD achieved fistula remission, and more required surgical intervention after anti-TNF therapy, suggesting that TNF antagonists may not be as effective in these patients.

Capsule endoscopy (CE) provides visualization of small bowel mucosa for evidence of inflammation. Given its ability to detect subtle mucosal changes, CE is recommended in the diagnostic work-up of small bowel Crohn disease (CD) and also in monitoring mucosal response to therapy in nonstricturing CD. Patency capsule and cross-sectional imaging can reduce risk of capsule retention in patients with suspected stenotic disease. CE is complementary to magnetic resonance enterography, which can provide extraintestinal information. Device-assisted enteroscopy has limited role in CD.

The review discusses the roles of small bowel capsule endoscopy and deep enteroscopy in patients with Crohn's disease. It highlights recent advances in the field and identifies areas where evidence is lacking.

Small bowel capsule endoscopy has an important role in the follow-up of patients with Crohn's disease after escalation of therapy and in the postoperative assessment period following surgical resection. Device-assisted enteroscopy offers the therapeutic advantage of small bowel dilatation, which may result in a reduction in the number of surgical resections required, thus avoiding long-term complications, such as short bowel syndrome and malabsorption.

Capsule endoscopy has an established role in the diagnosis and management of small bowel Crohn's disease. It is used in the setting of suspected Crohn's disease when ileocolonoscopy is negative and for the assessment of extent of small bowel disease in established Crohn's disease. It is relatively well tolerated because of the provision of patency capsule endoscopy to minimize the risk of inadvertent capsule retention. Device-assisted enteroscopy aids with the diagnosis of Crohn's disease as it enables histology to be taken from inflamed areas within the small bowel. Therapeutic procedures can be carried out during device-assisted enteroscopy including dilatation of Crohn's disease-related strictures and retrieval of retained capsules.

Perianal Crohn's disease (CD) prevalence varies according to the disease location, being particularly frequent in patients with colonic involvement. We aimed to evaluate small bowel involvement and compare small bowel capsule endoscopy findings and inflammatory activity between patients with and without perianal disease.

Retrospective single-center study including 71 patients - all patients with perianal CD (17 patients) who performed a small bowel capsule endoscopy were included, and non-perianal CD patients were randomly selected (54 patients). Clinical and analytical variables at diagnosis were reviewed. Statistical analysis was performed with SPSS v21.0 and a two-tailed p value <.05 was defined as indicating statistical significance.

Patients had a median age of 30 ± 16 years with 52.1% females. Perianal disease was present in 23.9%. Patients with perianal disease had significantly more relevant findings (94.1% vs 66.6%, p = .03) and erosions (70.6% vs 42.6%, p = .04), however, no differences were found between the two groups regarding ulcer, villous edema and stenosis detection. Overall, patients with perianal disease had more frequently significant small bowel inflammatory activity, defined as a Lewis Score ≥135 (94.1% vs 64.8%, p = .03), and higher Lewis scores in the first and second tertiles (450 ± 1129 vs 0 ± 169, p = .02 and 675 ± 1941 vs 0 ± 478, p = .04, respectively). No differences were found between the two groups regarding third tertile inflammatory activity assessed with the Lewis Score.

Patients with perianal CD have significantly higher inflammatory activity in the small bowel, particularly in proximal small bowel segments, when compared with patients without perianal disease.

Video capsule endoscopy (CE) provides a noninvasive option to assess the small intestine, but its use with respect to endoscopic procedures and cross-sectional imaging varies widely. The aim of this consensus was to provide guidance on the appropriate use of CE in clinical practice.

A systematic literature search identified studies on the use of CE in patients with Crohn's disease, celiac disease, gastrointestinal bleeding, and anemia. The quality of evidence and strength of recommendations were rated using the Grading of Recommendation Assessment, Development, and Evaluation (GRADE) approach.

The consensus includes 21 statements focused on the use of small-bowel CE and colon capsule endoscopy. CE was recommended for patients with suspected, known, or relapsed Crohn's disease when ileocolonoscopy and imaging studies were negative if it was imperative to know whether active Crohn's disease was present in the small bowel. It was not recommended in patients with chronic abdominal pain or diarrhea, in whom there was no evidence of abnormal biomarkers typically associated with Crohn's disease. CE was recommended to assess patients with celiac disease who have unexplained symptoms despite appropriate treatment, but not to make the diagnosis. In patients with overt gastrointestinal bleeding, and negative findings on esophagogastroduodenoscopy and colonoscopy, CE should be performed as soon as possible. CE was recommended only in selected patients with unexplained, mild, chronic iron-deficiency anemia. CE was suggested for surveillance in patients with polyposis syndromes or other small-bowel cancers, who required small-bowel studies. Colon capsule endoscopy should not be substituted routinely for colonoscopy. Patients should be made aware of the potential risks of CE including a failed procedure, capsule retention, or a missed lesion. Finally, standardized criteria for training and reporting in CE should be defined.

CE generally should be considered a complementary test in patients with gastrointestinal bleeding, Crohn's disease, or celiac disease, who have had negative or inconclusive endoscopic or imaging studies.

Small bowel capsule endoscopy (CE) was first introduced 15 years ago, and a large amount of literature has since been produced, focused on its indication, diagnostic yields, and safety. Guidelines that have made CE the primary diagnostic tool for small bowel disease have been created. Since its initial use in the small bowel, CE has been used for the esophagus, stomach, and colon. The primary indications for small bowel CE are obscure gastrointestinal bleeding, unexplained iron deficiency anemia, suspected Crohn's disease, small bowel tumors, nonsteroidal anti-inflammatory drug enteropathy, portal hypertensive enteropathy, celiac disease, etc. Colon CE provides an alternative to conventional colonoscopy, with possible use in colorectal cancer screening. Guidelines for optimal bowel preparation of CE have been suggested. The main challenges in CE are the development of new devices with the ability to provide therapy, air inflation for better visualization of the small bowel, biopsy sampling systems attached to the capsule, and the possibility of guiding and moving the capsule by an external motion controller. We review the current status and future directions of CE, and address all aspects of clinical practice, including the role of CE and long-term clinical outcomes.

Video capsule endoscopy (VCE) was launched in 2000 and has revolutionized direct endoscopic imaging of the gut. VCE is now a first-line procedure for exploring the small bowel in cases of obscure digestive bleeding and is also indicated in some patients with Crohn's disease, celiac disease, and polyposis syndrome. A video capsule has also been designed for visualizing the esophagus in order to detect Barrett's esophagus or esophageal varices. Different capsules are now available and differ with regard to dimensions, image acquisition rate, battery life, field of view, and possible optical enhancements. More recently, the use of VCE has been extended to exploring the colon. Within the last 5 years, tremendous developments have been made toward increasing the capabilities of the colon capsule. Although colon capsule cannot be proposed as a first-line colorectal cancer screening procedure, colon capsule may be used in patients with incomplete colonoscopy or in patients who are unwilling to undergo colonoscopy. In the near future, new technological developments will improve the diagnostic yield of VCE and broaden its therapeutic capabilities.

Video capsule endoscopy (CE) since its introduction 13 years back, has revolutionized our approach to small intestinal diseases. Obscure gastrointestinal bleed (OGIB) continues to be the most important indication for CE with a high sensitivity, specificity as well as positive and negative predictive values. It is best performed during ongoing bleed or immediately thereafter. Overt OGIB has a higher diagnostic yield than occult OGIB. However, even in iron deficiency anemia, CE is emerging as important investigation after initial negative work up. In suspected Crohn's disease (CD), CE has been shown superior to traditional imaging and endoscopic technique and should be considered after a negative ileocolonoscopy. Although CE has also been used for evaluating established CD, a high capsule retention rate precludes its use ahead of cross-sectional imaging. Celiac disease, particularly where gastro-duodenoscopy cannot be performed or is normal, can also be investigated by CE. Small bowel tumor, hereditary polyposis syndrome, and non-steroidal anti-inflammatory drugs induced intestinal damage are other indications for CE. Capsule retention is the only significant adverse outcome of CE and occurs mostly in presence of intestinal obstruction. This can be prevented by use of Patency capsule prior to CE examination. Presence of cardiac pacemaker and intracardiac devices continue to be relative contraindications for CE, though data do not suggest interference of CE with these devices. Major limitations of CE today include failure to control its movement from outside, inability of CE to acquire tissue for diagnosis, and lack of therapeutic help. With ongoing interesting and exciting developments taking place in these areas, these issues would be solved in all probability in near future. CE has the potential to become one of the most important tools in diagnostic and possibly in the therapeutic field of gastrointestinal disorder.

Small bowel imaging and endoscopy in IBD have undergone a tremendous change and advancement in the recent years. Modalities shifted from gastroscopy, colonoscopy and small bowel follow through to ileocolonoscopy, CT or MR enteroscopy, wireless video capsule endoscopy and balloon-assisted enteroscopy.

We reviewed the present role of endoscopy in assessing the small bowel in the context of IBD.

Endoscopy has a major role in the diagnosis of IBD, in the assessment of its extent, treatment of complications, assessment of the success of various medications and as a predictor of disease course. Wireless capsule endoscopy (WCE) is a relatively new tool allowing direct, patient-friendly visualization of the entire small bowel mucosa. It has gained a substantial role in the evaluation of patients with suspected Crohn's disease (CD) and indeterminate colitis. WCE has a high positive predictive value in patients with suspected CD, when one uses more than two of the International Conference on Capsule Endoscopy criteria, and not less important a very high negative predictive value in patients with suspected CD. Its role in patients with known CD, in the assessment of their disease activity and extent, assessment of postsurgical small bowel recurrence and evaluation of mucosal healing is still unclear. Balloon-assisted enteroscopy has established its role as a complementary tool in cases where there is a need for biopsy or treatment (dilatation of strictures).

The present review summarizes the role of endoscopy in the assessment of the small bowel in the context of IBD.

The diagnostic significance of single-balloon enteroscopy (SBE) in patients presenting with Crohn's disease (CD)-like anorectal fistula is unknown. We experienced 11 cases undergoing SBE due to CD-like fistulas between December 2007 and April 2013. The mean interval from fistula onset to SBE was 19.2 months with a range of 1.3-44.7. Prior to SBE, all patients underwent anorectal examination under anesthesia (EUA), and 9 patients underwent total colonoscopy with terminal ileal cannulation (TCS-I). One of 7 patients undergoing upper gastrointestinal endoscopy had CD-like gastritis. EUA revealed CD fissures in 7 patients, 1 of whom had no intestinal lesion. Primary TCS-I identified early lesions, such as aphthes and small ulcers, in 4 patients. Among the other 5 patients without any intestinal lesions with TCS-I, SBE indicated early lesions in 3 patients. One of 2 patients who initially underwent SBE without TCS-I showed multiple aphthes. Of the 11 patients, only 4 patients fulfilled the definitive Japanese diagnostic criteria for CD and 7 remained 'suspected CD' cases. Intrinsic anorectal fistulas as a presenting symptom of CD may be an early predictor of bowel lesions. SBE has the potential to reveal incipient disease because an early ileal lesion is not rare for patients with anorectal fistulas.

Small bowel capsule endoscopy (SBCE) was introduced 13 years ago by Given Imaging (Yokneam, Israel). It has become one of the most important investigational tools of the small bowel. The capsule is swallowed with water after a 12 h fast, propelled via peristalsis through the gastrointestinal tract and excreted naturally. A nonvideo patency capsule was developed to confirm functional patency of the gastrointestinal tract.

Four additional companies have introduced competitive small bowel video capsules, some of which are Food and Drug Admistration (FDA) approved. Due to the easiness of the procedure, SBCE has become a first-line tool to detect small bowel abnormalities. The main indications for SBCE include obscure gastrointestinal bleeding, suspected Crohn's disease, small bowel tumors and practically any abnormal small bowel imaging. New indications are emerging like small bowel motility and monitoring of drug therapy and mucosal healing. The present review will describe the available capsules in the market, the procedure itself, present indications and future expectations. It will focus on the PillCam SB of Given Imaging as it is the one on which most of the literature is written.

Over the past 10 years, SBCE has become a routine, first-line investigational tool of many small bowel pathologies.