Rationale and Objectives
Obscure gastrointestinal bleeding (OGIB) is the bleeding from the gastrointestinal tract without definite source that persists and recurs after a negative endoscopic evaluation. The study aimed to systematically evaluate the diagnostic accuracy of computed tomography enterography on OGIB detection by meta-analysis.
Materials and Methods
Studies were searched in relevant databases. With predefined inclusion criteria, eligible studies were included, followed by quality assessment using the Quality Assessment of Diagnostic Accuracy Studies scoring system. The Meta-DiSc software was used to implement the meta-analysis, and sensitivity, specificity, positive likelihood ratio, negative likelihood ratio, and diagnostic odds ratio with their 95% confidence intervals (CIs) were used as the effect size. Publication bias was determined by Egger test.
Results
A set of nine studies was included in this meta-analysis, having a relatively high quality. Under the random effects model, the pooled sensitivity and specificity were 0.724 (95% CI: 0.651–0.789) and 0.752 (95% CI: 0.691–0.807), respectively. Under the fixed effects model, the pooled positive likelihood ratio, negative likelihood ratio, and diagnostic odds ratio were 2.949 (95% CI: 2.259–3.850), 0.393 (95% CI: 0.310–0.497), and 9.452 (95% CI: 5.693–15.692), respectively. The area under curve of the summary receiver operating characteristic curve was 0.7916 (95% CI: 0.723–0.860). No obvious publication bias was detected (t = 1.62, P = .181).
Conclusions
Computed tomography enterography might be used as a complementary to video capsule endoscopy instead of an alternative for the detection of OGIB.
Introduction
Gastrointestinal (GI) bleeding is a common clinical emergency. Annually, the incidence of GI bleeding is estimated about 150 per 100,000 persons, and the mortality is varied from 2% to 10% . Obscure GI bleeding (OGIB) is designated as the bleeding from the GI tract without definite source that persists and recurs after a negative endoscopic evaluation, and it accounts for nearly 5% of all GI hemorrhage cases . Based on whether the bleeding is visible or, OGIB is classified into two types as overt or occult bleeding .
With the standard endoscopic techniques, there is a huge challenge on diagnosis of patients with OGIB because it is hardly accessible to the jejunum and ileum . The video capsule endoscopy (VCE), a noninvasive diagnostic method for the entire small bowel, has been identified as the first-line evaluation tool for OGIB . Other advanced endoscopic methods like deep enteroscopy (eg, single-balloon enteroscopy, double-balloon enteroscopy, and spiral enteroscopy) have been developed for a better identification of the small bowel bleeding sites . Despite these improvements, the diagnostic results are undesirable, and the diagnostic yield of VCE is only 32%–83% . Meanwhile, VCE has its own limitations. For instance, its high sensitivity in occult bleeding might reduce the specificity. Additionally, the images of VCE tend to be obscured by blood, which could conceal the location of underlying lesion . Having the advantages of easy operation and extra evaluation on small bowel strictures, the computed tomography (CT) is often considered as a complementary of VCE . CT enterography (CTE) integrates the resolution of CT with the neutral oral contrast agents, which allows detailed visualization of the small intestines . For the diagnosis of potential small bowel bleeding, CTE, in combination with VCE, has a significantly greater sensitivity than VCE or CTE alone ( P < .05), but the sample size with 52 patients is relatively small . A meta-analysis has been published to evaluate the yield of CTE in evaluating OGIB, compared to CE, double-balloon enteroscopy, and digital subtraction angiography , and finds that CTE has a better diagnostic result than other alternate modalities in the evaluation of OGIB, especially of overt bleeding. However, detailed sensitivity and specificity of CTE have not been evaluated.
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Methods
Literature Search
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Inclusion and Exclusion Criteria
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Data Extraction and Quality Assessment
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Statistical Analysis
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Results
Eligible Studies and Their Characteristics
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TABLE 1
Characteristics of the Included Studies
First Author Year Country Study Year Gender (M/F) Age (y) Channels Diagnostic Method Reference Standard TP FP FN TN QUADAS score Khalife et al 2011 France 2007.1–2009.8 19/13 55.9 ± 20.3 64 CTE Pathology, surgery, endoscopy 11 0 5 16 10 Hara AK 2009 USA 2006.6–2007.7 NA NA 16/64 CTE Pathology, endoscopy, angiography 2 9 3 17 9 Lee SS 2011 Korea 2005.8–2007.7 46/19 18–85 16/64 CTE Surgery, endoscopy, clinical follow-up 16 0 13 32 10 Huprich JE 2008 USA NA 11/11 37–83 64 CTE Surgery, conventional angiography, colonoscopy 8 2 6 6 9 Onoda et al 2010 Japan 2008.4–2009.7 NA NA 64 CTE Endoscopy 7 2 7 8 10 Chu Y 2016 China 2007.7–2014.7 60/61 51.1 ± 17.1 NA CTE Pathology 25 27 5 64 11 He B 2014 China 2008.5–2013.9 12/10 54.1 ± 19.1 64 CTE,CTA Double-balloon enteroscopy, digital subtraction angiography, intraoperative pathologic examination 10 6 1 5 9 Li J 2016 China 2011.2–2015.5 40/24 18–65 NA CTE Capsule endoscopy 42 8 0 14 8 Miller FH 2004 USA 1998.7–2011.11 NA NA NA CTE Angiography 5 2 4 8 10
CTA, computed tomography angiography; CTE, computed tomography enteroclysis; FN, false negatives; FP, false positives; M/F, male/female; NA, not available; QUADAS, quality assessment tool of diagnostic accuracy studies; TN, true negatives; TP, true positives.
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Pooled Effect Size of the Diagnostic Indicators
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Publication Bias
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Discussion
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Conclusion
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Acknowledgments
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