Comparison Of CT Enterography(CTE) And Capsule Endoscopy(CE) For Small Bowel Diseases

BackgroundThe small intestine ranges from 5 to 7 m in length, extending from the pylorus to the ileocecal valve, and is divided into 3 regions (duodenum, jejunum, ileum) based on structural and functional considerations. The organ is tasked with a complex array of functions, including nutrient, electrolyte, and water absorption, and is richly innervated with both extrinsic and intrinsic neurons that manage its motor physiology. The small bowel receives its vascular supply via the superior mesenteric artery with the jejunum and ileum suspended by a thin, broad-based mesentery attached to the posterior abdominal wall, allowing free movement within the abdomen. Historically, despite its anatomic simplicity, accurate medical evaluation of the small bowel has proved to be more elusive. The organ is located deep within the abdomen, where its length, mobility, and tortuosity present significant challenges to effective radiograph-ic and endoscopic evaluation. Consequently, small bowel disease often has been dif-ficult to diagnose, resulting in repetitive testing and poor clinical outcomes. The standard evaluation traditionally consisted of a mixed combination of push enter-oscopy, barium small-bowel follow-through, and computed tomography (CT).Most of the technique above present poor diagnostic rate in small bowel disease. Hence, to develop a reliable method of diagnosing small bowel disease have became an im-portant challenge for clinicians.A wide range of diagnostic imaging modalities is available for evaluating the small bowel, which mainly includes two parts:radiology and endoscopy. Radiologi-cal examination of the small bowel including barium X-ray, Computed tomography enterography (CTE), Magnetic resonance enterography,(MRE) and Digital subtrac-tion angiography (DSA), Emission Computed Tomography (ECT) and so on. Small bowel endoscopy modalities mainly consist of double balloon enteroscopy and cap-sule endoscopy. Each methods mentioned above have its own advantages and disad-vantages. X-ray barium examination consist of small bowel follow through(SBFT), small bowel enema(SBE), small bowel double contrast and method of enema inflation. Advantages of X-ray barium examination include its wide availability, low cost and portability. Historically, it was the standard first-line modalities to evaluating the small bowel disease. But they are generally much less sensitive and specific for pa-thology compared with techniques such as CT. Nowadays, X-ray barium examination is being replaced by new cross-section radiology modalities, such as CT and MR. CT has become a widely used technique for examining the SB in recent years, either by CT enteroclysis(CTEc)or by CT enterography(CTE). The role of CTE in the diag-nosis of SBDs has been gradually expanded and evolving with recent technical ad-vances of multi-slices CT(MSCT)technology. CTEc overcomes the individual defi-ciencies of both barium enteroclysis and conventional CT and combines the ad-vantages of both into one technique whose clinical applicability has been simplified and made more reliable with spiral and MDCT. But CTEc is a relative invasive method. Patients need to suffer from intubation of the small bowel, which limits its application. Similarly, Magnetic resonance enterography and enteroclysis also show a reliable quality in imaging the small bowel. However, its high cost and long time of imaging has prevented it from becoming the first-line tool. Digital subtraction angi-ography (DSA) allows physicians to perform interventional treatment of vascular disease or tumor with abundant supply of the small bowel. However, inability of providing a effective observation of the mucosa and lumen of small intestine had lim-ited the application range of DSA. Meckel scan is a useful tool for detecting Meckal’s diverticulum. Limitations of this method includes:not capable of qualitative diagnose, unable to precise positioning, and hard to distinguish bleeding site from hemorrhage site through radionuclide stain. hence, it’s not a ideal first-line screening tool for dis-eases of the small intestine.Comparing to all the modalities above, CT enterography (CTE) and capsule en-doscopy(CE) share the advantages of high diagnostic rate, relative low cost and non-invasive which made these two method become the first-line modalities to evaluate the small bowel.CTE was first described by Raptopoulos et al, which is an noninvasive peroral method of evaluating the small bowel by obtaining good distention and combines the improved spatial and temporal resolution of CT with large volumes of ingested emet-ic contrast material to permit visualization of the small bowel wall and lumen.Capsule endoscopy, also known as wirelesses CE, was initially invented and developed by Given Image Corp. at the beginning of this century. The widespread use of capsule endoscopy during the last several years has revolutionized small bowel imaging by providing a consistent and noninvasive method for complete visualization and assessment of the mucosa. Trials have repeatedly shown that capsule endoscopy is more sensitive than standard endoscopic and radiographic techniques and identifies lesions throughout the small bowel.The common clinical application of small bowel evaluation include:occult gas-trointestinal bleeding, inflammatory small bowel disease, small bowel tumor, intesti-nal obstruction and ileus, abdominal pain and so on. Consequently, small bowel dis-ease often has been difficult to diagnose, resulting in repetitive testing and poor clini-cal outcomes. Hence, gastroenterologists are eager to developed a reliable and cost-effective modalities to evaluate the small bowel. Nowadays, CE and CTE seem to fit this expectation. As these two method being widely use, one burning question rise:which modality is the best first-line tool? It seems that we should make the deci-sion according to the clinical situation. But when to use which one? There is no con-sensus in China. And seldom study aimed to answer these questions. To better under-stand the advantage and disadvantage of CTE and CE, we undertake a retrospect study of comparing characteristics(including lesions detection rate of whole small bowel, characteristic and location of the founded lesions, diagnostic accuracy) of CTE and CE in evaluating small bowel disease.Objective:To retrospectively analyze the data of patients who underwent both CTE and CE from a single center with 3 years’experience, comparing the characteristics of CTE and CE in diagnosing small bowel diseases. Providing evidence of which modality to choose in different clinical situation.Material and Methods:In our center, Domestic OMOM CE system and Intro medic Microcam CE sys-tem was introduced in 2005 and 2012 respectively. CTE examination was introduced in 2011.A retrospective analysis was conducted from the data of patients who underwent both CTE and CE(interval time< 2 weeks) procedure in a single-center (from Nov. 2011 to Dec.2014), including collection of demographic data, other inspections prior to CTE or CE procedure, indications for CTE or CE, management after CTE or CE examination.Statistical analysisData analysis of retrospective study was performed by statistical software SPSS version 13.0 for Windows. McNemar χ2 test(namely pairedχ2 test) was used to com-pare the diagnostic yields between CE and CTE. A p value< 0.5 (two-sided)was considered statistically significant.Result:A total of 53 patients underwent both CTE and CE(interval time< 2 weeks),exclude 2 patients with bowel lumen insufficiently filled,1 patients with a his-tory of small bowel surgery and 3 patients failed to finish CE examination.47 pa-tients meet the inclusion criteria were included with mean age 36.3 years old(range 17-76 years old).17 patients underwent CTE prior to CE and 30 of them undertook the examination in an opposite order.35 patients are male and 12 of them are female. The most common indication of small bowel evaluation is known or suspected Crohn’s disease(27 suspected, lknown),follow by 14 patients with unexplained ab-dominal pain,3 with OGIB,1 with protein losing enteropathy,1 with incomplete small bowel obstruction.1,Final diagnosisThe know or suspected CD group:21 patients was diagnosed as Crohn’s,5 pa-tients intestinal tuberculosis,1 as duodenum ulcer,1 as Perianal abscess. The ab-dominal pain group:9 patients diagnosed as Functional Gastrointestinal Disorders,1 as intestinal adhesions,1 as abdominal cramps,1 as hookworm infection,1 as unclear etiology. The OGIB group:1 patients diagnosed as Meckel diverticulum,1 as intesti-nal angiectasis,1 as multiple myeloma. Patients with incomplete small bowel ob-struction underwent CE examination after reliving obstruction, then diagnosed as small bowel medium differentiated adenocarcinoma. Patients with protein losing en-teropathy diagnosed as lymphangiectasia.2, Comparison of diagnostic yield and accuracyDiagnostic yield of CTE and CE for whole small bowel disorders showed no significant difference (CTE vs. CE:83.0% vs.78.7%, p=0.791)A accurate diagnose was defined as matching both nature and location of lesions to final diagnose.For Suspected or established CD, accuracy of CE in this group was 78.5%(22 of 28).5 patients with parenteral disorders and one emission CD patients only present-ing lesion in lumen wall with normal mucosa were diagnosed when Combining CTE. Accuracy of CTE was 35.7%(10 of 28).13 patients with jejunum lesions,4 patients with ileum lesions were diagnosed and one patient had been excluded the diagnosis of CD when combining CE. CE has a higher diagnostic accuracy than CTE (CTE vs. CE: 35.7% vs.78.6%, p=0.002),CE founded extra jejunum lesion in 13 patients while CTE only founded one more. Sensitivity of CE of detecting lesions in the jejunum was significance (CTE vs. CE:7.1% vs.50%, p=0.002) better than CTE. While there is no difference in detecting ileum lesions (CTE vs. CE:83.0% vs.78.7%, p=0.791). Diagnostic accuracy reached 100% when combining two methods. For patients with abdominal pain, diagnostic accuracy of combining CTE and CE was 85.6%. No significant difference was found in the diagnostic accuracy of CE and CTE (CTE vs.CE:42.8% vs.50%, p=1.00)Conclusion:1. CTE and CE were of equal value in detecting small bowel lesions.2. For patients with suspected or established CD, CE was a better diagnostic tool than CTE.3. For patients with unexplained abdominal pain, a combination of CTE and CE maybe a better strategy than using CTE or CE alone.