Diagnostic Value Of Double-balloon Enteroscopy And Capsule Endoscopy For Suspected Small Bowel Diseases

BackgroundSmall bowel (SB) is the longest part of entire gastrointestinal tract and considered as a blind spot in the past because of limitations of traditional methods such as push enteroscopy (PE) and colonoscopy. Conventional endoscopes can be performed to investigate proximal SB and terminal ileum, respectively. Small bowel diseases (SBDs) has low prevalence and nonspecific manifestations, plus deep location in the digestive tract, the diagnosis and treatment of patients with SBDs may be delayed, contributing to huge medical cost and poor prognosis. Early identification, diagnosis and timely intervention of SBDs become extremely important in clinical practice. With advent of capsule endoscopy (CE) and balloon-assisted enteroscopy (BAE), patients with SBDs can be early diagnosed and treated by theses advanced techniques with endoscopic biopsy(BAE), their application innovates a new era for diagnostics and management of SBDs.CE, also known as wirelesses CE, was initially invented and developed by Given Image Corp. at the beginning of this century. Compared with traditional noninvasive methods such as small bowel barium study and CT, CE can be performed to investigate the entire SB according intestinal movements because of its characteristics of noninvasiveness, non-radioactive hazard, higher detection rate and fewer complications. Currently, CE has been widely used in clinical practice. The findings of numerous clinical trials showed that CE has high diagnostic yields in patients with suspected SBDs, obscure gastrointestinal bleeding (OGIB), suspected/ known small bowel tumors(SBTs), suspected/known Crohn’s diseases (CD).Double-balloon enterosocopy (DBE) was firstly reported in2001and applied into clinical practice in2003. Compared with traditional invasive PE, DBE with two balloons at the end of the overtube and the enteroscopy overcomes the shortcomings of length of PE, which can be operated to grip the intestine by inflating the balloon so as to insert into distal SB. In addition, DBE can be performed by endoscopist back and forth to conduct biopsy, positional mark and therapeutic management. Similarly, a lot of clinical trials have confirmed that DBE has high diagnostic yields in patients with suspected SBDs, OGIB, SBTs, CD and has excellent safety in clinical practice. Currently, DBE can be not only used to investigate the SB, but also performed to investigate the upper gastrointestinal tract, the lower digestive tract, biliary tract and altered gastrointestinal anatomy. The application of DBE is a major progress of endoscopic technology development in the21st century.Meckel’s diverticulum(MD) is the most common congenital malformation in the gastrointestinal tract, which is a true diverticulum. Epidemiological studies show that MD occurs in less than2%of the population and more common in men, which is divided into symptomatic MD and asymptomatic MD. Symptomatic MD is frequently found in childhood and the aldults, and asymptomatic MD may not be examined during the lifetime of patient with MD. Although it is rare, complications of MD may lead to uncontrolled hemorrhagic shock arising from acute gastrointestinal bleeding, serious infectious peritonitis from intestinal perforation, intestinal obstruction/intussusception, etc. Currently, preoperative diagnosis of MD is relative low and MD is found incidentally by surgical exploration. There are few reports regarding to diagnosis of MD by DBE or CE although the both methods have been used to be compared each other in patients with OGIB, suspected CD and SBTs. As far as comparative diagnosis of patients with MD is concerned, there is lack of clinical study for comparison between CE and DBE.Gastrointestinal mesenchymal tissue tumors (GIMTs), including myogenic tumors, neurogenic tumors and gastrointestinal stromal tumor (GISTs), account for less than10%of gastrointestinal tumors. Radiological imagings(such as barium study, computed tomography(CT) and angiography) is usually performed to examine small bowel GIMTs without the application of CE and double-balloon enteroscopy (DBE). Barium study is feasible for diagnosis of biggish intraluminal SBTs; CT is used to locate the lesion, assess for invasion and detect metastasis of SBTs. GIMTs are common in the different part of SB. Their true incidences might be higher than those studies reported previously because novel methods such as CE and BAE are much more sensitive and specific in diagnosing GIMTs than conventional methods. Several studies indicated that DBE is a safe and effective procedure that enables accurate diagnosis of SBTs. To date, few studies have reported the diagnosis of GIMTs by DBE and elucidated their clinical and endoscopic features. Furthermore, rare studies have compared diagnosis of GIMTs by DBE and CE.The application of CE poses a significant challenge on conventional radiological examinations. Moreover, number of publications and experts suggested that CE should be a first-line tool for diagnosis of SBDs because of its advantages of invasiveness and higher diagnostic yield when compared with traditional methods. Even so, radiologic imaging still plays an important role in the diagnosis of patients with suspected/established SBDs. CT has become a widely used technique for examining the SB in recent years, either by CT enteroclysis(CTEc)or by CT enterography(CTEg). The role of CTE in the diagnosis of SBDs has been gradually expanded and evolving with recent technical advances of spiral and multidetector row CT (MDCT) technology. CTEc overcomes the individual deficiencies of both barium enteroclysis and conventional CT and combines the advantages of both into one technique whose clinical applicability has been simplified and made more reliable with spiral and MDCT. Number of clinical trials suggested that this technique is reliable method in the diagnostics of SBDs due to its characteristics of well-tolerance and easy to perform, either for suspected/known SBTs or for suspected/established Crohn’s disease (CD). CTEg was first described by Raptopoulos et al, which is an noninvasive peroral method of evaluating the SB by obtaining good distention and combines the improved spatial and temporal resolution of CT with large volumes of ingested enteric contrast material to permit visualization of the SB wall and lumen. Following studies revealed that CTEg is an accurate diagnostic imaging for SBDs, including luminal and extraluminal pathology. Magnetic resonance imaging (MRI) technique has also evolved as a powerful tool in recent years and is playing an increasing role of in the evaluation of SBDs, especially application of MR enteroclysis/enterography (MREc and MREg). Strengths of MRI include the superior soft-tissue contrast, lack of ionizing radiation, and the implementation of fast scanning techniques. Furthermore, both extraluminal and intraluminal abnormalities can be investigated through cross-sectional imaging. And that adequate luminal distention is achieved by MRE, combined with contrast enhancement and functional information, help to make an accurate diagnosis. Several studies have shown the advantages of this technique over traditional enteroclysis due to improvements in spatial and temporal resolution combined with improved bowel distending agents. Currently, there are still controversies in the diagnosis of SBDs between CTE/MRI and CE. Firstly, the findings of a crowd of clinical trials and perspectives proposed by experts suggested that CE should be the first-line tool for evaluation of suspected SBDs due to its higher yield when compared with other traditional modalities, excellent safety and rare complications. However, other studies showed that CE has a low yield for evaluation of suspected SBDs in patients with abdominal pain or diarrhea and cannot be recommended as a first-line test without further study. But it facilitates diagnosis in9%of patients with negative endoscopic and radiologic examinations. Secondly, some experts suggested that the diagnostic value of MRE and CTE is sufficient for clinical management of most patients with suspected SBDs, and thus CE may be omitted or at least postponed for later usage. CTE and MRE should be the first-line modality in the imaging of CD and is considered the most appropriate imaging modality in patients with suspected CD. The third point of view is that CE detects more SB lesions and is greatly superior to CTE/MRE for diagnosing SBDs, CE plays a major role and CTE/MRE only acts as a complementary and selective role. Fourthly, the three modalities play complementary role in the diagnostics of SBDs. As three different kinds of alternative modalities in clinical practice, CTE/MRI and CE are performed to compare their diagnostic yield of SBDs because there is still debatable problem. However, the results from clinical trials are inconclusive and contradictory. To date, there is no meta-analysis published to compare these methods and evaluate the diagnostic yields. To assess diagnostic efficiency of the these modalities for investigation of SBDs, we undertook a meta-analysis of studies that reported head-to-head comparison of diagnostic yield between CTE/MRI and CE.Objectives1. To retrospectively analyze the data of patients who underwent DBE from a single center with nine year’s experience, and elucidate the characteristics of SBDs in a single-center Chinses population;2. To retrospectively analyze the observational data collected from patients who underwent examination with CE, DBE, or both to evaluate DBE in the diagnosis of MD and to compare its diagnostic yield with that of CE.3. To retrospectively analyze the data collected from patients who underwent examination with DBE, CE, or both to evaluate DBE in the diagnosis of GIMTs and to compare its diagnostic yield with that of CE.4. To compare diagnostic performance of CE, CTE and MRI in patients with suspected SBDs based on evidence-based medince.Materials and MethodsDepartment of Gastroenterology, Nanfang Hospital in Guangzhou is one the earliest endoscopic unit with introduction of small bowel endoscopy in China. DBE system was introduced in2003and domestic OMOM CE system was introduced in2005.1. DBE for diagnosis of suspected SBDs:nine-years’ experience from a single-centerA retrospective analysis was conducted from the data of patients who underwent a DBE procedure in a single-center with nine years’ experience in China (from2003to May2012), including collection of demographic data, other inspections prior to DBE procedure, indications for DBE, positive biopsy rate, management after DBE examination. 2. DBE and/or CE for diagnostic value of MDThe current study was to assess the value of DBE in the diagnosis of MD and comparatively evaluate the diagnostic yield of DBE and CE for MD. A single-center study was performed on patients with a confirmed diagnosis of MD by surgery and postoperative pathology between January2003and December2011. A follow-up was conducted as well.3. DBE and/or CE for to diagnosis of GIMTs, and analysis of clinical and endoscopic features of GIMTsA retrospective review in a total of783patients who underwent a DBE procedure from January2003to December2011was conducted. Data from patients with pathologically confirmed GIMTs were analyzed at a single tertiary center with nine years’experience. The primary outcomes assessed included characteristics of patients with GIMTs, indications for DBE, overall diagnostic yield of GIMTs, endoscopic morphology, positive biopsy, comparison of diagnosis with CE, and subsequent interventional management.4. Systematic review and meta-analysis for diagnosis of suspected/known SBDs between CE and CTE/MRIBased on computer-aided strategy, we searched electronic database Medline (January2001-November2012), EMbase (January2001-November2012), Cochrane central register of controlled trials (January2001-November2012), Web of Knowledge (January2001-November2012). Abstracts published in international conferences and potential literatures were performed by manual search. Studies regarding head-to head comparison CE with CTE/MRI were included. Main outcomes assessed inlucded diagnostic yield of CE CTE/MRI, the second outcomes evaluated were diagnostic yields of suspected/confirmed CD, suspected/confirmed SBTs, and patients with OGIB.Statistical analysisData analysis of retrospective study was performed by statistical software SPSS version17.0for Windows. Continuous data were presented as means, mean±SD or range, and categorical variables were expressed as frequency or percentages. The x2 test or Fisher’s exact probability test was used to compare differences in categorical variables examined. Agreement analysis was assessed by the Kappa statistic:a kappa value<0.4indicates poor agreement, between0.4and0.7indicates moderate agreement, and>0.7indicates good agreement. McNemar’sχ2test (namely pairedχ2test) was used to compare the diagnostic yields between CE and DBE. A P value<0.05(two-sided) was considered statistically significant.The software STATA/SE version11.2(Stata, College Station, TX) was used to conduct statistical analysis of data synthesis and analysis. Effect size for pooled discontinuous variables was expressed as odds risks (ORs) and mean difference with95%confidence interval (95%CI). P value<0.05was considered statistically significant. The heterogeneity cross studies was evaluated by calculating the I2statistic of inconsistency with a cutoff point of I2=50%. And then random effect model was used when I2statistic>50%and P value<0.05. Publication bias was evaluated by funnel plot and examined by the Egger’s and Begg’s tests. Subgroup analysis was conducted on the basis of CTEc and CTEg, MREc and MREg. Sensitivity analysis was conducted based on the study design.Results1. Nine years’ experience of DBE application in patients with suspected SBDs at a single centerA total of825patients underwent DBE investigation, with mean age41.3±16.3years (range8-84years). Male accounted for71.3%of all the patients. Obscure gastrointestinal bleeding(OGIB) was the most common indication for DBE investigation, accounting for50.2%(39.2%of overt-OGIB and11.0%occult-OGIB, respectively), followed by abdominal pain (36.8%), abdominal distention (3.8%), patient’s requirement for screening (3.8%), diarrhea (2.4%), vomiting (1.7%), debilitation(0.8%), weight loss(0.5%).Blood test, defecate convention examination (including fecal occult blood testing), ECG, abdominal X-ray and abdominal ultrasound were regularly performed in the patients registered in our care unit. Each patient received at least one kind of other medical examination, including colonoscopy (80.7%), gastroscopy (79.0%), computed tomography (CT)(23.5%), barium study (20.1%), Meckel’s scan (8.1%), angiography (4.8%), bone marrow aspiration (3.0%), push entroscopy(2.5%), magnetic resonance imaging (MRI)(2.2%). Patients with confirmed diagnosis were not obtained by above examinations.262patients received CE examination; two of them receive CE after DBE procedure beyond duration of two weeks and has no diagnosis by CE.260of them patients received CE prior to DBE within an interval of two weeks. CE identified lesions/suspected lesions in187patients, definite diagnosis was finally determined in150patients (57.7%). Complications occurred in17patients (6.5%), including incomplete intestinal obstruction (1case), incomplete entire SB examination because of CE with running out of charge (1case), timely reconnection after disconnection of the CE data line (1case), CE retention (14cases). CE retention primarily occurred in patients with intestinal ulcers and stricture (13cases).260patients who received tandom CE and DBE,188of them were definitely diagnosed by DBE. Comparison of diagnostic yield between CE and DBE was seen in Table1. *P=1.000.A total of825patients underwent1159DBE procedures, including antegrade approach for294patients, retrograde approach for231patients and combination of the two approaches for300patients. Total enteroascopy (antegrade approach alone or antegrade+retrograde approachs) was achieved in120patients (14.5%).368patients with SBDs were identified by antegrade DBE, with44.6%of lesion detection rate;284patients with SBDs were identified by retrograde DBE, with34.4%of lesion detection rate.385patients received endoscopic biopsy, positive biopsy was achieved in54of them and the positive biopsy rate was14.0%.602patients with lesions (with73.0%of lesion detection rate) were detected by DBE, including missed lesions in the stomach and the colon in5cases (0.6%) and11cases (1.3%), respectively.552patients with SBDs were definitely diagnosed by DBE, and the diagnostic yield was66.9%. Finally,624patients with confirmed diagnosis had gastrointestinal lesions based on following management, including608patients with SBDs. Inflammatory/infectious diseases were the most common findings of SBDs, with a proportion of50.2%. Next was primary SB tumor (SBT)(20.2%), followed by abnormalities of intestinal tube (16.0%), vascular lesions (5.1%), metastatic intestinal tumor (1.5%), other miscellaneous lesions (7.1%).Based on confirmed location of lesion, intestinal lesions were most frequently detected in the ileum (25.5%), followed by the jejunum (24.6%), multiple parts of the SB(16.7%), duodenum (5.6%).Patients with confirmed SBDs received medical treatment such as pharmacotherapy, endoscopic intervention (tissue sampling, homeostasis, CE retrieval (CE retrieval was successfully performed by DBE in8patients), polyp resection, and surgical procedure (275cases, including all patients with MD and SBTs). Three patients underwent intraoperative endoscopy (including1case with Bean syndrome,2cases with acute massive gastrointestinal bleeding).Five patients occurred adverse events during and after DBE procedures. Intestinal perforation arised from MD with ulcer was recorded in one case after retrograde DBE and was verified by surgical procedure. Two patients had mild pancreatitis after oral DBE procedures and received conservative therapy. Rupture of a balloon equipped with the overtube was reported in two patients during the antergrade and the retrgrade procedure, respectively, patients with discomfort was not recorded. The patients completed DBE investigation after a new overtube was equipped. A few patients complained of mild laryngeal discomfort after the peroral approach, without special treatment.1patient died from acute massive hemorrhagic shock because the casue of hemorrhage was not found by intraoperative DBE. Another patient died from other diseases.2. DBE and/or CE for diagnosis of MDA total of783patients underwent1071DBE procedures for diagnosis or interventions of gastrointestinal diseases. Of these patients, a definite diagnosis of MD was established in74inpatients by surgery and postoperative pathological examination after DBE. With a mean age of29.0±14.3years (range,8±76years), the patients underwent DBE mainly for melena/hematochezia (64cases), abdominal pain (8cases), or diarrhea (2cases). Of the74MD patients,26patients also underwent CE before DBE. Some patients had previous examinations with a gastrointestinal barium study (15cases), computed tomography (12cases), digital subtraction angiography (6cases), or magnetic resonance imaging (2cases) before admission into our center.A total of26patients received a traditional Meckel’s scan before and after both methods. It was performed in20patients before CE and/or DBE and yielded negative results in14cases, suspected diagnosis of MD in3cases, and definite diagnosis of diverticula in3cases. After CE and/or DBE, Meckel’s scan was used in6patients and yielded positive results in5cases.All74patients successfully completed the preoperative DBE procedure. Only one patient complained of persistent abdominal pain and intermittent vomiting after DBE, which was found to result from acute peritonitis caused by diverticulum perforation, as confirmed by subsequent surgery. One patient underwent an endoscopic intervention for hemostasis. Compared with the operative and pathologic diagnosis, preoperative DBE showed a diagnostic yield of DBE of86.5%(64/74) for MD.Six patients underwent DBE via the peroral approach, which resulted in clear diagnoses of MD in4cases, one without lesion and one with overt massive bleeding in the ileum. Forty-five patients underwent DBE via the peranal approach, and only5had definite diagnoses other thanMD, including3with suspected gastrointestinal stromal tumors (GISTs), one with misdiagnosed intestine duplication, and another without lesions because of massive bleeding. The remaining23patients were examined with a combination of both approaches, and total enteroscopy was successfully completed in10patients. The combined approaches resulted in the diagnosis of MD in20cases (all found via a retrograde approach), detected overt bleeding in1case (via a combined approach), and identified no obvious lesions in2cases.In the10patients with no definite diagnoses or misdiagnoses by DBE, open or laparoscopic surgeries were carried out for removal of the suspicious masses (GIST) in3cases, intestine duplication in one case, and emergency surgery was performed in1case for perforation of the diverticulum. The other5patients underwent subsequent Meckel’s scintigraphy, and a suspected diagnosis of diverticulum was made in4patients, who then received exploratory laparotomy to locate the site of gastrointestinal bleeding. Inverted MD initially misdiagnosed as GISTs by DBE in3cases was finally confirmed by an operative procedure and pathology.Operative and pathologic findings demonstrated that single diverticulitis was the most common pathology in the MD lesions (40.5%), followed by diverticulum with concurrent ectopic gastric mucosa (31.1%), diverticulitis associated with ulcer (20.3%), diverticulum with ectopic gastric mucosa and pancreatic tissues (5.4%), and diverticulum with heterotopic pancreatic tissues (2.7%).All26patients undergoing both CE and DBE procedures completed the examinations successfully. CE was easily swallowed and excreted by the patients without any complications, as confirmed by X-ray. In one case, the data line of CE was disconnected from the image recorder but soon reconnected. A total of37DBE procedures were performed in the26patients, and no patients complained of obvious discomfort during or after the procedure. The overall diagnostic yield of DBE for MD was84.6%, which was significantly greater than that of CE (7.7%, P<.000, McNemar’sx2test). Poor agreement was found between the findings of DBE and CE (kappa=0.03).All patients received a range of1month to5years follow-up in the form of a telephone interview; the clinical symptoms disappeared after the operative procedure was performed. It was notable that4(3males and1female) were diagnosed as having small bowel Crohn’s disease2years after surgery and received treatment in our center.3. DBEand CE for diagnosis of small bowel GIMTs and characteristics of small bowel GIMTsA total of77inpatients who underwent DBE were identified; their final diagnoses were confirmed as GIMTs by histopathology and/or surgery. The mean age was47.74±14.14years (range:20-77years), with63.6%being males. The majority of patients presented with GI bleeding, accounting for81.8%, followed by abdominal pain, accounting for10.4%.All the patients underwent other medical examinations prior to DBE, including gastroduodenoscopy (73cases), colonoscopy (66cases), and push enteroscopy (1case), and yielded negative or suspected diagnoses. Barium study was conducted in10patients, only one patient was suspected of having a SBT. Twelve patients received CT scan, SBT was found in two patients and suspected SBT was found in one patient. Two patients were found to have suspected SBT by magnetic resonance imaging,2by angiography,3by Meckel’s scan and2by bone marrow aspiration.Thirty-one patients underwent CE examination before DBE within an interval of two weeks. All patients successfully completed CE procedures which reached the colon. Positive diagnoses were made in11patients, and suspected diagnoses in8 patients. No lesion was detected in12patients. No complications occurred during and after the procedure.Thirty-seven DBE procedures were performed in31patients, including22antegrade approaches,3retrograde approaches, and6combinations of the two approaches. The sensitivity of DBE and CE for the diagnosis of GIMTs was93.5%and61.3%, respectively. DBE for the diagnosis of GIMTs was superior to CE (P=0.006, McNemar’s χ2test).A total of93DBE procedures were performed in77patients, including49antegrade DBE approaches,12retrograde DBE approaches and16combinations of the two approaches. Total enteroscopy (TE) was achieved in3patients. Lesions were found in the small bowel in71patients, the detection rate for GIMTs being92.2%. Clear diagnosis was established in68patients, and the diagnostic yield of DBE for GIMTs was88.3%. Multiple tissue samplings were made in41cases; positive diagnoses were obtained in5cases. Only one therapeutic procedure was performed in one patient, i.e., a leiomyoma (8mm) was removed by DBE. All the patients successfully completed the entire DBE procedure, without any complications occurring during and after the procedure.Among9patients with unclear diagnosis by DBE, one was found with overt, ongoing bleeding, and two were found with single ulcerative lesions in proximal small bowel, respectively. No abnormality was found in six patients, including two patients treated with the combination of the two approaches (neither completed TE), one with the antegrade approach, the other three with the retrograde approach. Patients with indefinite diagnoses underwent surgical procedures (laparotomy or laparoscopic exploration) because of persistent symptoms. Five patients had GIMTs with extraluminal growth confirmed by surgery; one patient undergoing the antegrade approach had a GIMT located in the ileum.Endoscopic diagnosis was established in the overwhelming majority of the patients. Most GIMTs presented as a single lesion under the endoscopic view, protruding into the intra-luminal mass in the small bowel. The unsmooth surface of the tumor was seen most frequently, showing the appearance of erosion or ulcer. The second frequent morphology was a mass with smooth surface, indicating a tumor with sessile base in a rounded or oval shape. Rare GIMTs presented with irregular shapes under endoscopic view.In this study, GIMTs with confirmed diagnoses included GIST (60cases), leiomyoma (6cases), lipoma (3cases), hemangioma (3cases), lymphangioma (3cases), fibrous histiocytoma (1case), and angiosarcoma (1case). Based on the primary sites of tumors, GIMTs in our study were all primary tumors verified surgically and pathologically. Two kinds of GIMTs were detected on the basis of site, including intra-and extra-luminal tumors. Intra-luminal GIMTs were detected most frequently and verified by endoscopy and surgery (Figures1,2). A single lesion was most frequently examined, except in two patients who had multiple lymphangiomas. GIMTs were detected most frequently in the jejunum (60cases), and next in the ileum (16cases) and duodenum (1case). No spread and metastasis was investigated and confirmed after surgical removal.The findings of DBE changed the therapeutic plan and enabled all the patients to receive early intervention. The clinical symptoms disappeared after surgery and all the patients felt an improvement in their conditions. They received an average follow-up time of14.5mos after intervention, and important improvements were obtained in the patients after DBE and surgical intervention. No complication was reported.4. Results of meta-analysis for comparison diagnosis of suspected/known SBDs between CE and CTE/MRI4.1Results of meta-analysis for comparison diagnosis of suspected/known SBDs between CE and CTE4.1.1Comparison of overall diagnostic yield between CE and CTE15trials met the inclusion criteria,8of them performed CT enteroclysis, and seven of them performed CT enterography. CE used in the included studies was a product of Given Corp.15trials involved a total of475individuals, including4retrospective studies. All of included studies reported the diagnostic yield of comparison between CE and CTE. CE was superior to CTE in the diagnosis of SBDs (OR=1.94,95%CI1.03-3.65;P=0.039), mainly for comparison with CT enteroclysis (OR=2.94,95%CI1.42-6.09;P=0.004), not with CT enterography(OR=1.20,95%CI0.45-3.22; P=0.714). Random-effect model was used because significantly statistical heterogeneity was detected cross the studies (x2=19.8; P<0.001,12=75.0%), but with no evidence of funnel plot asymmetry(Egger’s and Begg’s tests, P>0.05, respectively).4.1.2Comparison of diagnostic yield between CE and CTE in patients with OGIB4studies reported diagnostic yields of CE and CTE in patients with OGIB, in total of114individuals. CE and CTE had comparable diagnostic yields in patients with OGIB (OR=1.2,95%CI0.71-2.05; P=0.50). No statistical heterogeneity was noted between studies (x2=3.51; P=0.319,I2=14.6%).4.1.3Comparison of diagnostic yield between CE and CTE in patients withsuspected and established CD9studies comparing CE with CTE involved in241subjects,7of which included patients with established CD. The pooled data indicated that CE was generally superior to CTE in the diagnosis of suspected and known CD (OR=2.77,95%CI1.24-6.17; P=0.013), mainly for comparison with CT enteroclysis(OR=4.11,95%CI1.88-8.97; P<0.001), not with CT enterography(OR=2.16,95%CI0.71-6.61; P=0.176), with statistical heterogeneity between studies(x2=22.84;P<0.004, I2=65.0%).4.1.4Comparison of diagnostic yield between CE and CTE in patients suspected and established SBTs4studies compared the yield of CE with CTE for the diagnosis of suspected and known SBTs. CE and CTE provided similar diagnostic yields in patients with suspected and known SBTs (OR=0.4,95%CI0.03-4.92; P=0.48), with significant heterogeneity cross the studies(x2=7.9; P=0.019,I2=74.7%).4.2Results of meta-analysis for comparison diagnosis of suspected/known SBDsbetween CE and MRI4.2.1Comparison of overall diagnostic yield between CE and MRI17studies (including three abstracts) were identified for comparison between CE and MRI in patients with suspected and established SBDs.7of included trials incorporated patients with known SBDs,6included patients with suspected and known SBDs, remains included patients with suspected SBDs.17trials included526individuals for comparison CE with MRI in the diagnostics of suspected and established SBDs. Pooled analysis indicated that CE was not superior to MRI for diagnosis of SBD(OR=1.51,95%CI0.89-2.56; P=0.127). Statistical heterogeneity was detected between the studies (x2=52.01; P<0.001, I2=69.2%) and thus a random effects model was applied. Subgroup analysis indicated that CE had similar diagnostic performance compared with MREg (OR=1.53,95%CI0.83-2.84; P=0.174) or MREc (OR=1.02,95%CI0.37-2.86; P=0.963).4.2.2Comparison CE with MRI in patients with OGIB4studies were identified for comparison of diagnostic performance between CE and MRI. CE provided higher diagnostic yield than that of MRI in patients with OGIB. The OR was3.88(95%CI1.83-8.23;P<0.001). There was no significant heterogeneity cross the studies (heterogeneity x2=3.21; P=0.36; I2=6.7%).4.2.3Comparison of CE and MRI in patients with suspected and established CD8trials were identified to compare CE with MRI in patients with suspected and known CD. Both modalities yielded similar diagnostic performance (OR=0.92,95%CI0.44-1.93;P=0.832)(heterogeneity x2=16.15; P=0.024;I2-=56.6%).4.2.4Comparison of CE and MRI in patients with suspected and established SBTs7trials recruited patients with suspected/established SBTs for comparison CE with MRI. Five of them included individuals with known familial adenomatous polyposis (FAP) or with established Peutz-Jeghers’ syndrome (PJS). Diagnostic efficacy of CE was not significantly different from that of MRI (OR=1.30,95%CI0.47-3.55; P=0.614). A random effects model was used because of statistical heterogeneity (heterogeneity x2=:9.57; P=0.048;I2=58.2%).Conclusions1. Combing previous reports from scatterd Chinese population, the current findings show that inflammatory/infectious diseases, primary small bowel tumors and intestinal malformation are the most common patholo...