Obscure gastrointestinal bleeding: diagnostic performance of multidetector CT enterography

Early intervention with double balloon enteroscopy for higher yield for inpatient overt obscure gastrointestinal bleeding: A propensity matched analysis

Background and Aim

Overt obscure gastrointestinal bleeding (OOGIB) is defined as continued bleeding with unknown source despite esophagogastroduodenoscopy (EGD) and colonoscopy evaluation. Small bowel evaluation through video capsule endoscopy (VCE) or double balloon enteroscopy (DBE) is often warranted. We studied the timing of DBE in hospitalized OOGIB patients regarding diagnostic yield, therapeutic yield, and GI rebleeding.

Methods

We performed a retrospective review of DBEs performed at a tertiary medical center between November 2012 and December 2020. The inclusion criterion was first admission for OOGIB undergoing DBE. Those without previous EGD or colonoscopy were excluded. Patients were stratified into two groups: DBE performed within 72 h of OOGIB (emergent) and beyond 72 h of OOGIB (nonemergent). Propensity score matching was used to adjust for the difference in patients in the two groups. Logistic regression analysis was used to assess factors associated with diagnostic and therapeutic yield. Kaplan-Meir survival curve showed GI bleed-free survival following initial bleed and was compared using the log rank test.

Results

A total of 154 patients met the inclusion criterion, of which 62 had emergent DBE and 92 had nonemergent DBE. The propensity-score-matched sample consisted of 112 patients, with 56 patients each in the emergent and nonemergent groups. Univariate and multivariable logistic regression analysis showed a significant association between VCE and emergent DBE and diagnostic and therapeutic yield (P < 0.05). Emergent DBE patients had increased GI bleed-free survival compared to those in the nonemergent group (P = 0.009).

Conclusion

Our data demonstrate that emergent DBE during inpatient OOGIB can impact the overall diagnostic yield, therapeutic yield, and GI rebleeding post DBE.

[Radiologic Diagnosis of Gastrointestinal Bleeding]

Gastrointestinal (GI) bleeding is not a single disease but a symptom and clinical manifestation of a broad spectrum of conditions in the GI tract. According to its clinical presentation, GI bleeding can be classified into overt, occult, and obscure types. Additionally, it can be divided into upper and lower GI bleeding based on the Treitz ligament. Variable disease entities, including vascular lesions, polyps, neoplasms, inflammation such as Crohn's disease, and heterotopic pancreatic or gastric tissue, can cause GI bleeding. CT and conventional angiographies and nuclear scintigraphy are all radiologic imaging modalities that can be used to evaluate overt bleeding. For the work-up of occult GI bleeding, CT enterography (CTE) can be the first imaging modality. For CTE, an adequate bowel distention is critical for obtaining acceptable diagnostic performance as well as minimizing false positives and negatives. Meckel's scintigraphy can be complementarily useful in cases where the diagnosis of CTE is suboptimal. For the evaluation of obscured GI bleeding, various imaging modalities can be used based on clinical status and providers' preferences.

"MURAL" model to predict bleeding from mural-based lesions in potential small bowel bleeding may improve diagnostic capability and decrease cost

In potential small bowel bleeding, video capsule endoscopy (VCE) is excellent to detect mucosal lesions, while mural-based lesions are better detected by computed tomography enterography (CTE). A predictive tool to identify mural-based lesions should guide selecting investigations. In this retrospective study, we developed and validated the "MURAL" model based on logistic regression to predicts bleeding from mural-based lesions. Cost-effectiveness analysis comparing diagnostic strategy among VCE, CTE, and MURAL model was performed. Of 296 patients, 196 and 100 patients were randomly included in the derivative and validation cohorts, respectively. The MURAL model comprises 5 parameters: age, presence of atherosclerosis, chronic kidney disease, antiplatelet use, and serum albumin level. The area under the receiver operating characteristic curve was 0.778 and 0.821 for the derivative and validation cohorts, respectively. At a cutoff value of 24.2%, the model identified mural-based lesions with 70% sensitivity and 83% specificity in the validation cohort. Cost-effectiveness analysis revealed that application of the MURAL model demonstrated a comparable missed lesion rate but had a lower missed tumor rate, and lower cost compared to VCE strategy. The model for predicting mural-based lesions provide some guidance in investigative decision-making, which may improve diagnostic efficiency and reduce costs.

Gallium-68-labeled fibroblast activation protein inhibitor PET in gastrointestinal cancer: insights into diagnosis and management

PURPOSE

Gallium-68-labeled fibroblast activation protein inhibitor (⁶⁸Ga-FAPI) is an emerging promising tumor tracer. This study aims to evaluate the diagnostic efficiency of ⁶⁸Ga-FAPI PET in gastrointestinal cancer, and to determine its potential impact on clinical management.

METHODS

Patients with malignancies were prospectively enrolled in a clinical trial to evaluate the diagnostic value of ⁶⁸Ga-FAPI PET. One hundred twenty patients with gastrointestinal malignancies (121 ⁶⁸Ga-FAPI PET scans) between June 2020 and May 2021 were retrospectively analyzed. Initial staging of untreated patients and restaging of treated patients were evaluated. The treatment scheme promoted by imaging was determined according to NCCN guidelines. Final diagnosis and treatment reference standards were determined by a dedicated multidisciplinary team. The diagnostic performance and treatment guidance of ⁶⁸Ga-FAPI PET were compared with those of conventional imaging (CI) and ¹⁸F-FDG PET.

RESULTS

The diagnostic accuracy of ⁶⁸Ga-FAPI PET was much higher than that of CI and ¹⁸F-FDG PET (95.0% vs. 65.1% and 69.0%, respectively, both p < 0.001). ⁶⁸Ga-FAPI PET revised diagnosis in 30.3% and 26.2% of patients compared with CI and ¹⁸F-FDG PET. The accordance rate of ⁶⁸Ga-FAPI PET-guided treatment in comparison with the reference standard was significantly higher than that of CI and ¹⁸F-FDG PET (96.7% vs. 75.2% and 76.2%, respectively, both p < 0.001). ⁶⁸Ga-FAPI PET changed treatment in 22.9% and 23.8% of patients compared with CI and ¹⁸F-FDG PET.

CONCLUSIONS

⁶⁸Ga-FAPI PET showed remarkable diagnostic performance in gastrointestinal cancer, resulting in more accurate staging and guidance for timely treatment revision, thereby having a critical impact on clinical management.

TRIAL REGISTRATION

NCT04554719. Registered September 8, 2020-retrospectively registered, http://clinicaltrails.gov/show/NCT04554719.

ACR Appropriateness Criteria® Radiologic Management of Lower Gastrointestinal Tract Bleeding: 2021 Update

Diverticulosis remains the commonest cause for acute lower gastrointestinal tract bleeding (GIB). Conservative management is initially sufficient for most patients, followed by elective diagnostic tests. However, if acute lower GIB persists, it can be investigated with colonoscopy, CT angiography (CTA), or red blood cell (RBC) scan. Colonoscopy can identify the site and cause of bleeding and provide effective treatment. CTA is a noninvasive diagnostic tool that is better tolerated by patients, can identify actively bleeding site or a potential bleeding lesion in vast majority of patients. RBC scan can identify intermittent bleeding, and with single-photon emission computed tomography, can more accurately localize it to a small segment of bowel. If patients are hemodynamically unstable, CTA and transcatheter arteriography/embolization can be performed. Colonoscopy can also be considered in these patients if rapid bowel preparation is feasible. Transcatheter arteriography has a low rate of major complications; however, targeted transcatheter embolization is only feasible if extravasation is seen, which is more likely in hemodynamically unstable patients. If bleeding site has been previously localized but the intervention by colonoscopy and transcatheter embolization have failed to achieve hemostasis, surgery may be required. Among patients with obscure (nonlocalized) recurrent bleeding, capsule endoscopy and CT enterography can be considered to identify culprit mucosal lesion(s). The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.

Evaluation of Low-Dose Multidetector Computed Tomography Whole Gastroenterography With Oral Administration of Contrast Agents

PURPOSE

To evaluate the degree of gastric, enteric, colonic, and rectal filling in multidetector computed tomography (MDCT) whole gastroenterography.

METHODS

In this prospective study involving 124 patients, 78 and 46 patients underwent MDCT whole gastroenterography using positive and neutral oral contrast agents, respectively. The degree of filling of the stomach, small and large bowel, was qualitatively analyzed by experienced radiologists using a 3-point scoring system.

RESULTS

The majority of patients received a score of ≥2 for small intestine filling using both positive and neutral contrast agents (90.5% and 78.2%, respectively), and <9% of the patients had a score of 0. The highest score for the degree of filling in the small intestine was observed in the ileum, followed by the duodenum and jejunum. There was a significant difference in the degree of filling achieved with positive and neutral contrast agents in the duodenum (P = .013) and jejunum (P = .047). More than 74% of cases had an optimal filling of the stomach, whereas >80% of the cases had an optimal filling of the colorectal segments. Only ≤5.1% had a score of 0 for the analyzed segments of the colorectum. Positive and neutral contrast agents were associated with similar degree of filling in the stomach and colon segments without a significant difference in the extent of contrast agent filling (P > .05).

CONCLUSIONS

Multidetector computed tomography whole gastroenterography was found to be a simple, safe, noninvasive, painless, and effective modality for the diagnosis of stomach and bowel complications in clinical settings.

Management of obscure gastrointestinal bleeding: Comparison of guidelines between Japan and other countries

Small-bowel bleeding accounts for the majority of obscure gastrointestinal bleeding, but it is caused by various types of small bowel disease, upper gastrointestinal disease, and colorectal disease. For the diagnosis, history taking and physical examination are required, leading to a determination of what diseases are involved. Next, cross-sectional imaging, such as computed tomography, should be carried out, followed by the latest enteroscopy such as small bowel capsule endoscopy and deep enteroscopy according to the severity of hemorrhage and patient condition. After a comprehensive diagnosis, medical, enteroscopic, or surgical treatment should be selected. This article reviews recent advances in the endoscopic diagnosis of obscure gastrointestinal bleeding and compares perspectives of the management of obscure gastrointestinal bleeding in Japan with that in other countries.

Multiphase Computed Tomographic Enterography: Diagnostic Yield and Efficacy in Patients With Suspected Small Bowel Bleeding

Objective

To estimate the diagnostic yield and efficacy of multiphase computed tomographic enterography (mpCTE) for suspected small bowel bleeding in routine clinical practice.

Patients and Methods

All mpCTEs performed between January 1, 2006, and December 31, 2014, for suspected small bowel bleeding were included and classified by a gastroenterologist and an abdominal radiologist. The reference standard for a definitive diagnosis was balloon-assisted enteroscopic, angiographic, surgical, or pathologic results. Overall and lesion-specific diagnostic yield (DY), sensitivity, and positive predictive value were calculated. The relationship of mpCTE diagnosis and continued bleeding or iron supplementation was examined using logistic regression in patients with at least 1 year of follow-up.

Results

We identified 1087 patients who had an initial mpCTE indication of small bowel bleeding. The overall DY was 31.6% (344 of 1087 patients; 95% CI, 29.0%-35.0%), higher for an indication of small bowel bleeding that was overt or occult with heme-positive stool vs occult with only iron-deficiency anemia (DY, 35.0% [170 of 486] and 35.3% [66 of 187] vs 26.1% [108 of 414]; P=.004 and P=.02, respectively). The highest sensitivity and positive predictive value were for small bowel masses (90.2% [55 of 61] and 98.2% [55 of 56], respectively). Higher risk of future bleeding and iron supplementation was seen with a negative result on mpCTE (odds ratio [OR], 1.91; 95% CI, 1.28-2.86), lack of surgical intervention (OR, 4.37; 95% CI, 2.31-8.29), or discrepant balloon-assisted enteroscopic findings (OR, 2.50; 95% CI, 1.03-6.09).

Conclusion

Multiphase computed tomographic enterography has a higher rate of detection in patients with overt bleeding or heme-positive stool. The procedure provides actionable targets for further intervention and leads to substantially reduced rates of rebleeding in long-term follow-up.

History of malignancy and relevant symptoms may predict a positive computed tomography enterography in obscure gastrointestinal bleeds

BACKGROUND AND AIM

This study aimed to assess the clinical utility of computed tomography enterography (CTE) and identify factors associated with a diagnostic CTE for patients with obscure gastrointestinal bleeding (OGIB).

METHODS

A retrospective observational study was performed at a Canadian tertiary care center from 2005 to 2015. A total of 138 patients underwent a CTE for OGIB. Univariate and multivariate logistic regressions were performed to determine factors associated with a diagnostic CTE. A highly sensitive clinical rule was then developed to help identify OGIB patients for whom a CTE may be beneficial in their clinical work-up.

RESULTS

A possible bleeding source was identified in 30 (22%) cases. The presence of abdominal or constitutional symptoms as well as history of colorectal cancer was significantly associated with a positive CTE in univariate and multivariate analyses (P < 0.05). A positive CTE could be predicted based on the presence of abdominal or constitutional symptoms and history of colorectal cancer with 90% sensitivity (95% CI 74-98%) in our population.

CONCLUSION

CTE identified a possible source of OGIB in one in five cases. In patients with the presence of abdominal or constitutional symptoms and a personal history of colorectal cancer, CTE may contribute to their diagnostic work-up.

Small Bowel Gastrointestinal Bleeding Diagnosis and Management-A Narrative Review

Background: Small bowel bleeding accounts for 5-10% of all gastrointestinal bleeding. Despite advances in imaging, endoscopy and minimally invasive therapeutic techniques, its diagnosis and treatment remains a challenge and a standardized algorithm for approaching suspected small bowel bleeding remains elusive. Furthermore, the choice of investigation is subject to timing of presentation and accessibility to investigations. The aim of this study was to construct a narrative review of recent literature surrounding the diagnosis and management of small bowel bleeding. Methods: A literature review was conducted examining the database pubmed with the following key words and Boolean operators: occult GI bleed OR mesenteric bleed OR gastrointestinal hemorrhage OR GI hemorrhage AND management. Articles were selected and reviewed based on relevance to the research topic. Where necessary, the full text was sought to further assess relevance. Results: In overt GI bleeding, CT angiography and red cell scintigraphy are both feasible and reliable diagnostic imaging modalities if standard endoscopy is negative. Red cell scintigraphy may be advantageous through detection of lower bleeding rates but it is subject to availability. Overt bleeding and a positive CT angiogram or red cell scan improves the diagnostic yield of formal angiography ± embolization. Video capsule endoscopy or double balloon endoscopy can be considered in occult GI bleeding following normal upper and lower endoscopy. Conclusions: Small bowel bleeding remains a rare but significant diagnostic and therapeutic challenge. Technological advances in diagnostics have aided evaluation but have not broadened the range of therapeutic interventions.

Diagnosis of chronic anaemia in gastrointestinal disorders: A guideline by the Italian Association of Hospital Gastroenterologists and Endoscopists (AIGO) and the Italian Society of Paediatric Gastroenterology Hepatology and Nutrition (SIGENP)

Anaemia is a common pathologic condition, present in almost 5% of the adult population. Iron deficiency is the most common cause; other mechanisms can be involved, making anaemia a multi-factorial disorder in most cases. Anaemia being a frequent manifestation in the diseases of the gastrointestinal tract, patients are often referred to gastroenterologists. Furthermore, upper and lower endoscopy and enteroscopy are pivotal to the diagnostic roadmap of anaemia. In spite of its relevance in the daily clinical practice, there is a limited number of gastroenterological guidelines dedicated to the diagnosis of anaemia. For this reason, the Italian Association of Hospital Gastroenterologists and Endoscopists and the Italian Society of Paediatric Gastroenterology, Hepatology and Nutrition commissioned a panel of experts to prepare a specific guideline on anaemia and its diagnostic roadmap in the gastroenterological scenario. The panel also discussed about the potential involvement of gastroenterologists and endoscopists in the management of patients with anaemia, with particular attention to the correct use of investigations. The panel paid particular attention to practical issues with the aim to support gastroenterologists in their clinical practice when dealing with patients with anaemia.

Diagnostic Value of Computed Tomography in Crohn's Disease Patients Presenting with Acute Severe Lower Gastrointestinal Bleeding

Objective

To investigate the diagnostic yield of contrast-enhanced computed tomography (CT) in Crohn's disease (CD) patients presenting with acute severe lower gastrointestinal bleeding (LGIB), and the role of CT in predicting the risk of rebleeding.

Materials and Methods

A consecutive series of 110 CD patients presenting with acute severe LGIB between 2005 and 2016 were analyzed. Among them, 86 patients who had undergone contrast-enhanced CT constituted the study cohort. The diagnostic yield of CT for detecting contrast extravasation was obtained for the entire cohort and compared between different CT techniques. In a subgroup of 62 patients who had undergone CT enterography (CTE) and showed a negative result for extravasation on CTE, the association between various clinical and CTE parameters and the risk of rebleeding during subsequent follow-up was investigated using Cox regression analysis.

Results

The diagnostic yield of CT was 10.5% (9 of 86 patients). The yield did not significantly differ between single-phase and multiphase examinations (p > 0.999), or between non-enterographic CT and CTE (p = 0.388). Extensive CD (adjusted hazard ratio [HR], 3.27; 95% confidence interval [CI], 1.09–9.80; p = 0.034) and bowel wall-to-artery enhancement ratio (adjusted HR, 2.81; 95% CI, 1.21–6.54; p = 0.016) were significantly independently associated with increased rebleeding risks, whereas anti-tumor necrosis factor-α therapy after the bleeding independently decreased the risk of rebleeding (adjusted HR, 0.26; 95% CI, 0.07–0.95; p = 0.041).

Conclusion

The diagnostic yield of contrast-enhanced CT was not high in CD patients presenting with acute severe LGIB. Nevertheless, even a negative CTE may be beneficial as it can help predict the risk of later rebleeding.

Radiologic Assessment of Gastrointestinal Bleeding

Gastrointestinal (GI) bleeding represents a broad differential of disease throughout the GI tract. The proper diagnostic evaluation of patients presenting with symptoms of GI bleeding depends on the overall clinical acuity and suspected source locations. The radiologic assessment of these patients is centered around computed tomography (CT) angiography, CT enterography, conventional angiography, and nuclear scintigraphy.

Uncontrolled bleeding of the gastrointestinal tract

PURPOSE OF REVIEW

Acute gastrointestinal bleeding is a frequent emergency situation, whose incidence will likely rise as a result of the increasing use of direct anticoagulants and of the medical progresses resulting in longer life expectancy with underlying comorbidities. Updated guidelines and improvements in the diagnostic and therapeutic tools are now available and will likely improve the management of massive gastrointestinal bleeding in the near future.

RECENT FINDINGS

The assessment of severity has been improved by validated scores useable upon admission. Massive blood transfusion protocols and specific care in case of bleeding of patients treated with direct anticoagulants, including concentrates of coagulation factors and monoclonal antibodies are now available. The endoscopic management has been facilitated by the use of hemostatic powders and by the use of self-expanding metal stents in case of variceal hemorrhage. New diagnostic tools include emergency video-capsule endoscopy, multiphasic computed tomography angiography and enterography.

SUMMARY

The implementation of multidisciplinary diagnostic and therapeutic algorithms for the management of massive bleeding requires a close collaboration between emergency physicians, intensivists, endoscopists, radiologists and surgeons. A sequential strategy involving each of these specialists is desirable for a successful management of acute and massive gastrointestinal bleeding.

Colonoscopy in Acute Lower Gastrointestinal Bleeding: Diagnosis, Timing, and Bowel Preparation

Lower gastrointestinal bleeding is bleeding from a colonic source. Rapid colon purge using 4 to 6 L of polyethylene glycol followed by early colonoscopy, within 24 hours of presentation, is recommended to optimize the detection and management of bleeding sources. Although the data are mixed, early colonoscopy seems to be associated with higher detection of bleeding lesions and therapeutic interventions. There is no clear benefit for early colonoscopy in terms of reduced duration of stay, rebleeding, transfusion requirement, or surgery compared with patients undergoing elective colonoscopy. Further studies are needed to determine the effect of early colonoscopy on clinically important outcomes.

Approach to the Diagnostic Workup and Management of Small Bowel Lesions at a Tertiary Care Center

BACKGROUND

Small bowel lesions (SBL) are rare, representing diagnostic and management challenges. The purpose of this cross-sectional study was to evaluate diagnostic modalities used and management practices of patients with SBL at an advanced endoscopic referral center.

METHODS

We analyzed patients undergoing surgical management for SBL from 2005 to 2015 at a single tertiary care center. Patients were stratified into gastrointestinal bleed/anemia (GIBA) or obstruction/pain (OP).

RESULTS

One hundred and twelve patients underwent surgery after presenting with either GIBA (n = 67) or OP (n = 45). The mean age of our study population was 61.8 years and 45% were women. Patients with GIBA were more likely to have chronic or acute-on-chronic symptoms (100% vs 67%) and more often referred from outside hospitals (82 vs. 44%) (p < 0.01). The most common preoperative imaging modalities were video capsule endoscopy (VCE) (96%) for GIBA and computer tomography CT (78%) for OP. Findings on VCE and CT were most frequently concordant with operative findings in GIBA (67%) and OP (54%) patients, respectively. Intraoperatively, visual inspection or palpation of the bowel successfully identified lesions in 71% of patients. When performed in GIBA (n = 26), intraoperative enteroscopy (IE) confirmed or identified lesions in 69% of patients. Almost all (90%) GIBA patients underwent small bowel resections; most were laparoscopic-assisted (93%). Among patients with OP, 58% had a small bowel resection and the majority (81%) were laparoscopic-assisted. Surgical exploration failed to identify lesions in 10% of GIBA patients and 24% of OP patients. Among patients who underwent resections, 20% of GIBA patients had recurrent symptoms compared with 13% of OP patients.

CONCLUSION

Management and identification of SBL is governed by presenting symptomatology. Optimal management includes VCE and IE for GIBA and CT scans for OP patients. Comprehensive evaluation may require referral to specialized centers.

Accuracy of Computed Tomographic Enterography for Obscure Gastrointestinal Bleeding: A Diagnostic Meta-analysis

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.

The effect of without using anisodamine during CT enterography on image quality, diagnostic performance and latent side effects

OBJECTIVE

To examine whether no anisodamine injection before CTE was feasible without impairing image quality and diagnostic performance.

MATERIALS

The change of mural thickness and luminal diameter were compared between using and no using anisodamine. The diagnostic performance of small-bowel disease was analyzed and compared.

RESULTS

No motion artifact was detected in two groups. There was no significant difference regarding the change of luminal diameter and mural thickness (all P>0.05). The diagnostic accuracy of small-bowel disease was no significant difference (P=0.63).

CONCLUSION

Lack of anisodamine injection before CTE did not impair image quality and diagnostic performance compared with CTEs performed with anisodamine injection.

A Prospective Blinded Comparison of Video Capsule Endoscopy Versus Computed Tomography Enterography in Potential Small Bowel Bleeding: Clinical Utility of Computed Tomography Enterography

GOALS

To compare the efficacy of video capsule endoscopy (VCE) with computed tomography enterography (CTE) in potential small bowel (SB) bleeding, and to identify factors predictive of a high diagnostic yield for CTE.

BACKGROUND

In potential SB bleeding, CTE potentially detects some lesions missed by VCE, but few data have determined its clinical utility.

STUDY

Consecutive patients with potential SB bleeding were prospectively enrolled. All underwent VCE and CTE within a 1-week interval. Definitive diagnoses were made by surgery or enteroscopy, except when a strategy of VCE and conservative management was suitable. The diagnostic yields and sensitivities of each investigation were measured.

RESULTS

Fifty-two patients were recruited (41 with overt and 11 with occult bleeding); 36 received a definitive diagnosis. The diagnostic yields and sensitivities of VCE and CTE were 59.6% and 30.8% (P=0.004), and 72.2% and 44.4% (P=0.052), respectively. The combined sensitivity of VCE and CTE (88.9%) was significantly greater than VCE (P=0.03) or CTE (P<0.01) alone. VCE was better for ulcers, enteritis, and angiodysplasia, whereas CTE was better for tumors and Meckel diverticula. Age below 40 years and severe bleeding were associated with a higher diagnostic yield for CTE [odds ratios (95% confidence interval)=7.3 (1.04-51.4), P=0.046 and 6.1 (1.4-25.5), P=0.014, respectively].

CONCLUSIONS

Both investigations complement each other in the diagnosis of potential SB bleeding. CTE should be considered when VCE is negative. Age below 40 years and severe bleeding were independent predictors of a higher diagnostic yield for CTE.

ACR Appropriateness Criteria® Nonvariceal Upper Gastrointestinal Bleeding

Upper gastrointestinal bleeding (UGIB) remains a significant cause of morbidity and mortality with mortality rates as high as 14%. This document addresses the indications for imaging UGIB that is nonvariceal and unrelated to portal hypertension. The four variants are derived with respect to upper endoscopy. For the first three, it is presumed that upper endoscopy has been performed, with three potential initial outcomes: endoscopy reveals arterial bleeding source, endoscopy confirms UGIB without a clear source, and negative endoscopy. The fourth variant, "postsurgical and traumatic causes of UGIB; endoscopy contraindicated" is considered separately because upper endoscopy is not performed. When endoscopy identifies the presence and location of bleeding but bleeding cannot be controlled endoscopically, catheter-based arteriography with treatment is an appropriate next study. CT angiography (CTA) is comparable with angiography as a diagnostic next step. If endoscopy demonstrates a bleed but the endoscopist cannot identify the bleeding source, angiography or CTA can be typically performed and both are considered appropriate. In the event of an obscure UGIB, angiography and CTA have been shown to be equivalent in identifying the bleeding source; CT enterography may be an alternative to CTA to find an intermittent bleeding source. In the postoperative or traumatic setting when endoscopy is contraindicated, primary angiography, CTA, and CT with intravenous contrast are considered appropriate. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.

Role of computed tomography angiography on the management of overt obscure gastrointestinal bleeding

Background and aim

The role of computed tomography angiography (CTA) on the management of acute overt obscure gastrointestinal bleeding (OGIB) remains unclear. We designed a study to evaluate the impact of CTA before enteroscopy for acute overt OGIB.

Methods

All patients undergoing CTA followed by enteroscopy for acute overt OGIB were enrolled in this retrospective study. Clinical characteristics and diagnosis were compared between patients with positive and negative CTA findings. We evaluated the impact of CTA on subsequent enteroscopy.

Results

From February 2008 to March 2015, 71 patients including 25 patients with positive CTA findings and 46 patients with negative CTA findings, were enrolled. All 25 patients with positive CTA findings were confirmed to have mid GI lesions, a significantly higher proportion than among patients with negative CTA findings (100% vs. 52.2%, respectively; P <0.001). CTA had a higher diagnostic yield for bleeding from tumor origin than from non-tumor origin (80.0% vs. 23.7%, respectively; P <0.001). The diagnostic yield of CTA and enteroscopy was 35.2% and 73.2%, respectively. The lesions could be identified by the initial route of enteroscopy in more patients with positive CTA findings than in those with negative CTA findings (92.0% vs. 47.8%, respectively; P <0.001). Lesions could be identified in seven of the 25 patients (28.0%) with positive CTA findings by using only push enteroscopy instead of single-balloon enteroscopy (SBE), but all 46 patients with negative CTA findings needed SBE for deep small-bowel examination.

Conclusions

CTA is useful in the diagnosis of acute overt OGIB, especially in patients with bleeding from tumors. In addition, it also can show the precise location of bleeding, and guide subsequent enteroscopic management.

Assessment of multi-modality evaluations of obscure gastrointestinal bleeding

AIM

To determine the frequency of bleeding source detection in patients with obscure gastrointestinal bleeding (OGIB) who underwent double balloon enteroscopy (DBE) after pre-procedure imaging [multiphase computed tomography enterography (MPCTE), video capsule endoscopy (VCE), or both] and assess the impact of imaging on DBE diagnostic yield.

METHODS

Retrospective cohort study using a prospectively maintained database of all adult patients presenting with OGIB who underwent DBE from September 1^st, 2002 to June 30^th, 2013 at a single tertiary center.

RESULTS

Four hundred and ninety five patients (52% females; median age 68 years) underwent DBE for OGIB. AVCE and/or MPCTE performed within 1 year prior to DBE (in 441 patients) increased the diagnostic yield of DBE (67.1% with preceding imaging vs 59.5% without). Using DBE as the gold standard, VCE and MPCTE had a diagnostic yield of 72.7% and 32.5% respectively. There were no increased odds of finding a bleeding site at DBE compared to VCE (OR = 1.3, P = 0.150). There were increased odds of finding a bleeding site at DBE compared to MPCTE (OR = 5.9, P < 0.001). In inpatients with overt OGIB, diagnostic yield of DBE was not affected by preceding imaging.

CONCLUSION

DBE is a safe and well-tolerated procedure for the diagnosis and treatment of OGIB, with a diagnostic yield that may be increased after obtaining a preceding VCE or MPCTE. However, inpatients with active ongoing bleeding may benefit from proceeding directly to antegrade DBE.

Accuracy of 99mTechnetium-labeled RBC Scintigraphy and MDCT With Gastrointestinal Bleed Protocol for Detection and Localization of Source of Acute Lower Gastrointestinal Bleeding

BACKGROUND

Acute lower gastrointestinal bleeding (LGIB) is a major cause of morbidity and mortality. Multidetector row computed tomography (CT) with gastrointestinal (GI) bleed protocol is a novel diagnostic technique for detecting and localizing LGIB. Being rapid and noninvasive, it may be useful as a first-line modality to investigate cases of acute LGIB.

GOALS

To assess and compare diagnostic accuracy of (99M)Technetium (Tc)-labeled red blood cell (RBC) scintigraphy and multidetector row CT with GI bleed protocol for detection and localization of source of acute LGIB.

STUDY

Requirement of informed consent was waived for this retrospective study. Seventy-six patients had undergone either RBC scintigraphy, CT with GI bleed protocol, or both, followed by conventional angiography for evaluation of acute persistent LGIB between January 2010 and February 2014 at our institution. Accuracy of both modalities was assessed using conventional angiography as reference standard and compared using the 2-tailed, Fisher exact test. A P-value of <0.05 was considered statistically significant.

RESULTS

Fifty-one, 20, and 5 patients had undergone RBC scintigraphy only, CT with GI bleed protocol only, and both modalities, respectively. Fourteen of 25 patients in the CT group had angiographic evidence of active bleeding as compared with 32 of 56 patients in the scintigraphy group. CT with GI bleed protocol had higher accuracy (96%) than (99M)Tc-labeled RBC scintigraphy (55.4%, P<0.001).

CONCLUSIONS

CT with GI bleed protocol was more accurate in detecting and localizing the source of acute LGIB as compared with (99M)Tc-labeled RBC scintigraphy.

CT enterography: technical and interpretive pitfalls

CT enterography is a first-line test at many institutions to investigate potential small bowel disorders. While numerous articles have focused on the ability of CT enterography to diagnose and stage Crohn's disease, small bowel neoplasia, and malabsorptive or vascular disorders, this article reviews CT enterography limitations, technical and interpretive pitfalls, image review tactics, and complementary radiologic and endoscopic examinations to improve diagnostic accuracy. CT enterography limitations include its inability to demonstrate isolated mucosal abnormalities such as aphthous ulcers and its use of ionizing radiation. The most common technical pitfall of CT enterography is inadequate small bowel distention resulting from inadequate ingestion, gastric retention, or rapid small bowel transit of a large volume of neutral enteric contrast material. Additionally, segments of jejunum are frequently collapsed. Interpretive pitfalls commonly result from peristaltic contractions, transient intussusception and opaque intraluminal debris. Opaque debris is especially problematic during multiphasic CT enterography performed to identify potential small bowel sources of obscure gastrointestinal bleeding. False-negative examinations may result from inadequate radiation dose. Examinations complementary to CT enterography include small bowel follow through, enteroclysis, CT enteroclysis, MR enterography, MR enteroclysis, capsule endoscopy, and balloon-assisted endoscopy. Properly performed and accurately interpreted CT enterography contributes to the diagnosis and management of small bowel disease by itself and as a complement to other radiologic and optical small bowel imaging examinations.

Gastrointestinal hemorrhage: evaluation with MDCT

Gastrointestinal (GI) bleeding is a common medical problem, with high associated morbidity and mortality. The clinical presentation of gastrointestinal hemorrhage varies with the location of the bleeding source, the intensity of the bleed, and the presence of comorbidities that affect the ability to tolerate blood loss. Conventional endoscopic examinations are usually the initial diagnostic tests in patients presenting with overt gastrointestinal hemorrhage. However, implementation of upper tract endoscopy and colonoscopy in the emergency setting can be challenging due to inconsistent availability of the service and difficulties in achieving adequate colonic cleansing in emergent situations. Thus, imaging tests are often relied upon to establish the location and the cause of bleeding, either for initial diagnosis or after non-revealing upper and lower tract endoscopies ("obscure" bleeding). This article discusses the imaging evaluation of patients with gastrointestinal bleeding and reviews the imaging appearance of the most common causes, taking into account the two most relevant clinical presentations: overt bleeding and obscure bleeding.

Lower Gastrointestinal Bleeding in Children

This article provides an overview of the evaluation and management of lower gastrointestinal bleeding (LGIB) in children. The common etiologies at different ages are reviewed. Conditions with endoscopic importance for diagnosis or therapy include solitary rectal ulcer syndrome, polyps, vascular lesions, and colonic inflammation and ulceration. Diagnostic modalities for identifying causes of LGIB in children include endoscopy and colonoscopy, cross-sectional and nuclear medicine imaging, video capsule endoscopy, and enteroscopy. Pre-endoscopic preparation and decision-making unique to pediatrics is highlighted. The authors conclude with a summary of current and emerging therapeutic hemostatic techniques that can be used in pediatric patients.

Multidetector CT Enterography versus Double-Balloon Enteroscopy: Comparison of the Diagnostic Value for Patients with Suspected Small Bowel Diseases

Aim. To compare the diagnostic value of multidetector CT enterography (MDCTE) and double-balloon enteroscopy (DBE) for patients with suspected small bowel diseases. Methods. From January 2009 to January 2014, 190 patients with suspected small bowel diseases were examined with MDCTE and DBE. The characteristics of the patients, detection rates, diagnostic yields, sensitivity, specificity, positive predictive value, and negative predictive value were described and analyzed. Results. The overall detection rates of DBE and MDCTE were 92.6% and 55.8%, respectively (P<0.05), while the overall diagnostic yields were 83.2% and 33.7%, respectively (P<0.05). The sensitivity, specificity, positive predictive value, and negative predictive value of DBE were all higher than those of MDCTE. DBE had a higher diagnostic yield for OGIB (87.3% versus 20.9%, P<0.05). The diagnostic yields of DBE were higher than those of MDCTE for inflammatory diseases, angioma/angiodysplasia, and diverticulums, while being not for gastrointestinal tumors/polyps. Conclusions. The diagnostic value of DBE for small bowel diseases is better than that of MDCTE as a whole, but if gastrointestinal tumors are suspected, MDCTE is also needed to gain a comprehensive and accurate diagnosis.

Diagnosis of Small-Bowel Diseases: Prospective Comparison of Multi-Detector Row CT Enterography with MR Enterography

PURPOSE

To prospectively compare the accuracies of computed tomographic (CT) enterography and magnetic resonance (MR) enterography for the detection and characterization of small-bowel diseases.

MATERIALS AND METHODS

The institutional review board approved the study protocol, and informed consent was obtained from all participants. From June 2009 to July 2013, 150 consecutive patients (81 men and 69 women; mean age, 38.8 years; range, 18-74 years), who were suspected of having a small-bowel disease on the basis of clinical findings and whose previous upper and lower gastrointestinal endoscopy findings were normal, underwent CT and MR enterography. Two independent readers reviewed CT and MR enterographic images for the presence of small-bowel diseases, for differentiating between inflammatory and noninflammatory diseases, and for extraenteric complications. The histopathologic findings of surgical (n = 23) and endoscopic (n = 32) biopsy specimens were used as the reference standard; the results of video-capsule endoscopy (n = 36) and clinical follow-up (n = 59) were used only to confirm the absence of small-bowel disease.

RESULTS

MR and CT enterography were successfully performed in all 150 patients. Overall sensitivity, specificity, and accuracy, respectively, in identifying patients with small-bowel lesions were 75.9% (41 of 54), 94.8% (91 of 96), and 88.0% (132 of 150) for CT enterography and 92.6% (50 of 54), 99.0% (95 of 96), and 96.7% (145 of 150) for MR enterography. The sensitivity of MR enterography was significantly higher than that of CT enterography for the detection of both overall small-bowel diseases (P = .0159) and neoplastic diseases (P = .0412) but not for the detection of inflammatory diseases (P > .99) or noninflammatory and nonneoplastic diseases (P = .6171).

CONCLUSION

MR enterography is more accurate than CT enterography in the detection of small-bowel diseases; MR enterography was more accurate in detecting neoplastic diseases in particular.

Expression of Angiogenic Factors in Patients With Sporadic Small Bowel Angiodysplasia

GOALS

To identify putative angiogenic factors associated with sporadic small bowel angiodysplasia (SBA).

BACKGROUND

SBAs account for 50% of obscure gastrointestinal bleeding and due to delays in diagnosis and ineffective treatments, are associated with high levels of morbidity and mortality. Treatment development is impeded by a limited knowledge of the pathophysiology behind SBA formation.

STUDY

We identified patients with definite sporadic SBA, and fecal immunochemical-negative controls were recruited from our institution's colorectal cancer screening program. Serum levels of VEGF, endoglin, Angiopoietin-2 (Ang-2), PDGF, Angiopoietin-1 (Ang-1), and TNF-α were measured using commercially available enzyme-linked immunosorbent assay kits. On the basis of serum results, we measured gene expression of target angiogenic factors in small bowel biopsy samples from angiodysplasias and unaffected tissue by quantitative PCR assessment.

RESULTS

Serum samples were analyzed from 40 SBA patients and 40 controls. Median serum levels of Ang-2 were significantly higher in patients than controls with levels of Ang-1 and TNF-α significantly lower. There were no differences in serum levels of VEGF, endoglin, or PDGF. Gene expression levels of Ang-1, Ang-2, and their receptor Tie2 were all significantly higher in biopsies from areas of angiodysplasia compared with normal small bowel.

CONCLUSIONS

This study, the first to explore the role of angiogenic factors in SBA, has identified a positive association between SBA and the Angiopoietin pathway, with increased serum and mucosal expression of Ang-2, which could potentially be used as a serum biomarker and future therapeutic target to improve outcome in affected patients.

ACG Clinical Guideline: Diagnosis and Management of Small Bowel Bleeding

Bleeding from the small intestine remains a relatively uncommon event, accounting for ~5-10% of all patients presenting with gastrointestinal (GI) bleeding. Given advances in small bowel imaging with video capsule endoscopy (VCE), deep enteroscopy, and radiographic imaging, the cause of bleeding in the small bowel can now be identified in most patients. The term small bowel bleeding is therefore proposed as a replacement for the previous classification of obscure GI bleeding (OGIB). We recommend that the term OGIB should be reserved for patients in whom a source of bleeding cannot be identified anywhere in the GI tract. A source of small bowel bleeding should be considered in patients with GI bleeding after performance of a normal upper and lower endoscopic examination. Second-look examinations using upper endoscopy, push enteroscopy, and/or colonoscopy can be performed if indicated before small bowel evaluation. VCE should be considered a first-line procedure for small bowel investigation. Any method of deep enteroscopy can be used when endoscopic evaluation and therapy are required. VCE should be performed before deep enteroscopy if there is no contraindication. Computed tomographic enterography should be performed in patients with suspected obstruction before VCE or after negative VCE examinations. When there is acute overt hemorrhage in the unstable patient, angiography should be performed emergently. In patients with occult hemorrhage or stable patients with active overt bleeding, multiphasic computed tomography should be performed after VCE or CTE to identify the source of bleeding and to guide further management. If a source of bleeding is identified in the small bowel that is associated with significant ongoing anemia and/or active bleeding, the patient should be managed with endoscopic therapy. Conservative management is recommended for patients without a source found after small bowel investigation, whereas repeat diagnostic investigations are recommended for patients with initial negative small bowel evaluations and ongoing overt or occult bleeding.

Diagnostic Performance of CT Angiography in Patients Visiting Emergency Department with Overt Gastrointestinal Bleeding

Objective

To investigate the diagnostic performance of computed tomography angiography (CTA) in identifying the cause of bleeding and to determine the clinical features associated with a positive test result of CTA in patients visiting emergency department with overt gastrointestinal (GI) bleeding.

Materials and Methods

We included 111 consecutive patients (61 men and 50 women; mean age: 63.4 years; range: 28-89 years) who visited emergency department with overt GI bleeding. They underwent CTA as a first-line diagnostic modality from July through December 2010. Two radiologists retrospectively reviewed the CTA images and determined the presence of any definite or potential bleeding focus by consensus. An independent assessor determined the cause of bleeding based on other diagnostic studies and/or clinical follow-up. The diagnostic performance of CTA and clinical characteristics associated with positive CTA results were analyzed.

Results

To identify a definite or potential bleeding focus, the diagnostic yield of CTA was 61.3% (68 of 111). The overall sensitivity, specificity, positive predictive value (PPV), and negative predictive value were 84.8% (67 of 79), 96.9% (31 of 32), 98.5% (67 of 68), and 72.1% (31 of 43), respectively. Positive CTA results were associated with the presence of massive bleeding (p = 0.001, odds ratio: 11.506).

Conclusion

Computed tomography angiography as a first-line diagnostic modality in patients presenting with overt GI bleeding showed a fairly high accuracy. It could identify definite or potential bleeding focus with a moderate diagnostic yield and a high PPV. CTA is particularly useful in patients with massive bleeding.

Lower gastrointestinal bleeding: Role of 64-row computed tomographic angiography in diagnosis and therapeutic planning

AIM: To determine the value of computed tomographic angiography (CTA) for diagnosis and therapeutic planning in lower gastrointestinal (GI) bleeding.

METHODS: Sixty-three consecutive patients with acute lower GI bleeding underwent CTA before endovascular or surgical treatment. CTA was used to determine whether the lower GI bleeding was suitable for endovascular treatment, surgical resection, or conservative treatment in each patient. Treatment planning with CTA was compared with actual treatment decisions or endovascular or surgical treatment that had been carried out in each patient based on CTA findings.

RESULTS: 64-row CTA detected active extravasation of contrast material in 57 patients and six patients had no demonstrable active bleeding, resulting in an accuracy of 90.5% in the detection of acute GI bleeding (57 of 63). In three of the six patients with no demonstrable active bleeding, active lower GI bleeding recurred within one week after CTA, and angiography revealed acute bleeding. The overall location-based accuracy, sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) for the detection of GI bleeding by 64-row CTA were 98.8% (249 of 252), 95.0% (57 of 60), 100% (192 of 192), 100% (57 of 57), and 98.5% (192 of 195), respectively. Treatment planning was correctly established on the basis of 64-row CTA with an accuracy, sensitivity, specificity, PPV and NPV of 98.4% (248 of 252), 93.3% (56 of 60), 100% (192 of 192), 100% (56 of 56), and 97.5% (192 of 196), respectively, in a location-based evaluation.

CONCLUSION: 64-row CTA is safe and effective in making decisions regarding treatment, without performing digital subtraction angiography or surgery, in the majority of patients with lower GI bleeding.

Obscure gastrointestinal bleeding: diagnosis and treatment

Small-bowel bleeding comprises a majority of obscure gastrointestinal bleeding, but is caused by various kinds of diseases. For its diagnosis, history-taking and physical examination is requisite, leading to a suspicion of what diseases are involved. Next, cross-sectional imaging such as computed tomography should be done, followed by the latest enteroscopy, videocapsule endoscopy and deep enteroscopy according to the severity of hemorrhage and patient conditions. After comprehensive diagnosis, medical, enteroscopic, or surgical treatment should be selected.

Evaluation and outcomes of patients with obscure gastrointestinal bleeding

Obscure gastrointestinal bleeding (OGIB) is defined as recurrent or persistent bleeding or presence of iron deficiency anaemia after evaluation with a negative bidirectional endoscopy. OGIB accounts for 5% of gastrointestinal bleeding and presents a diagnostic challenge. Current modalities available for the investigation of OGIB include capsule endoscopy, balloon assisted enteroscopy, spiral enteroscopy and computed tomography enterography. These modalities overcome the limitations of previous techniques. Following a negative bidirectional endoscopy, capsule endoscopy and double balloon enteroscopy remain the cornerstone of investigation in OGIB given their high diagnostic yield. Long-term outcome data in patients with OGIB is limited, but is most promising for capsule endoscopy. This article reviews the current literature and provides an overview of the clinical evaluation of patients with OGIB, available diagnostic and therapeutic modalities and long-term clinical outcomes.

Obscure gastrointestinal bleeding: diagnostic performance of 64-section multiphase CT enterography and CT angiography compared with capsule endoscopy

OBJECTIVE

To compare the diagnostic capabilities between capsule endoscopy (CE) and multislice CT (MSCT) enterography in combination with MSCT angiography for assessment of obscure gastrointestinal bleeding (OGIB).

METHODS

A total of 127 patients with OGIB were looked at in this study. 82 patients (aged 42.7 ± 19.1 years; 34 males) were assigned to receive MSCT diagnosis and 67 patients to (aged 53.9 ± 16.2 years; 28 males) receive CE diagnosis. Among them, 22 patients (aged 54.1 ± 19.1 years; 12 males) received both examinations. Oral isotonic mannitol and intramuscular injection of anisodamine were performed; non-ionic contrast (iopromide, 370 mg I ml(-1)) was intravenously administered; and then multiphase scanning was conducted at arterial, small intestinal and portal venous phases in MSCT. The results were compared with findings of reference standards including double balloon enteroscopy, digital subtraction angiography, intraoperative pathological examination and/or clinical diagnosis.

RESULTS

Administration of anisodamine markedly increased the satisfaction rate of bowel filling (94.67% vs 28.57%; p < 0.001) but not the diagnostic yield (p = 0.293) of MSCT. Compared with MSCT, CE showed an improved overall diagnostic yield (68.66% vs 47.56%; p = 0.010), which was also observed in overt bleeding patients (i.e. patients with continued passage of visible blood) (76.19% vs 51.02%; p = 0.013) and in patients aged younger than 40 years of age (85% vs 51.28%; p = 0.024). However, CE had similar positive rates to MSCT (p > 0.05). Among the 22 cases in whom both examinations were conducted, CE showed no significantly different diagnostic capability compared with MSCT (p = 0.4597).

CONCLUSION

Both CE and MSCT are safe and effective diagnostic methods for OGIB.

ADVANCES IN KNOWLEDGE

CE is preferred for overt bleeding or patients aged younger than 40 years. The combined use of CE and MSCT is recommended in OGIB diagnosis.

Small bowel bleeding: a comprehensive review

The small intestine is an uncommon site of gastro-intestinal (GI) bleeding; however it is the commonest cause of obscure GI bleeding. It may require multiple blood transfusions, diagnostic procedures and repeated hospitalizations. Angiodysplasia is the commonest cause of obscure GI bleeding, particularly in the elderly. Inflammatory lesions and tumours are the usual causes of small intestinal bleeding in younger patients. Capsule endoscopy and deep enteroscopy have improved our ability to investigate small bowel bleeds. Deep enteroscopy has also an added advantage of therapeutic potential. Computed tomography is helpful in identifying extra-intestinal lesions. In cases of difficult diagnosis, surgery and intra-operative enteroscopy can help with diagnosis and management. The treatment is dependent upon the aetiology of the bleed. An overt bleed requires aggressive resuscitation and immediate localisation of the lesion for institution of appropriate therapy. Small bowel bleeding can be managed by conservative, radiological, pharmacological, endoscopic and surgical methods, depending upon indications, expertise and availability. Some patients, especially those with multiple vascular lesions, can re-bleed even after appropriate treatment and pose difficult challenge to the treating physician.

Multidetector CT angiography for acute gastrointestinal bleeding: technique and findings

Acute gastrointestinal bleeding is a common reason for emergency department admissions and an important cause of morbidity and mortality. Factors that complicate its clinical management include patient debility due to comorbidities; intermittence of hemorrhage; and multiple sites of simultaneous bleeding. Its management, therefore, must be multidisciplinary and include emergency physicians, gastroenterologists, and surgeons, as well as radiologists for diagnostic imaging and interventional therapy. Upper gastrointestinal tract bleeding is usually managed endoscopically, with radiologic intervention reserved as an alternative to be used if endoscopic therapy fails. Endoscopy is often less successful in the management of acute lower gastrointestinal tract bleeding, where colonoscopy may be more effective. The merits of performing bowel cleansing before colonoscopy in such cases might be offset by the resultant increase in response time and should be weighed carefully against the deficits in visualization and diagnostic accuracy that would result from performing colonoscopy without bowel preparation. In recent years, multidetector computed tomographic (CT) angiography has gained acceptance as a first-line option for the diagnosis and management of lower gastrointestinal tract bleeding. In selected cases of upper gastrointestinal tract bleeding, CT angiography also provides accurate information about the presence or absence of active bleeding, its source, and its cause. This information helps shorten the total diagnostic time and minimizes or eliminates the need for more expensive and more invasive procedures.

Reducing radiation dose in CT enterography

Computed tomographic (CT) enterography is a diagnostic examination that is increasingly being used to evaluate disorders of the small bowel. An undesirable consequence of CT, however, is patient exposure to ionizing radiation. This is of particular concern with CT enterography because patients tend to be young and require numerous follow-up examinations. There are multiple strategies to reduce radiation dose at CT enterography, including adjusting acquisition parameters, reducing scan length, and reducing tube voltage or tube current. The drawback to dose reduction strategies is degradation of image quality due to increased image noise. However, image noise can be reduced with commercial iterative reconstruction and denoising techniques. With a combination of low-dose techniques and noise-control strategies, one can markedly reduce radiation dose at CT enterography while maintaining diagnostic accuracy.

MDCT and CT angiography evaluation of rectal bleeding: the role of volume visualization

OBJECTIVE

This article reviews several different causes of rectal bleeding and the role of MDCT in diagnosis.

CONCLUSION

Although colonoscopy remains the first-line modality for the diagnosis of lower gastrointestinal tract bleeding, colonoscopy may not be possible for unstable patients, and moreover, even for patients who undergo colonoscopy, the examination may still fail to diagnose a cause for bleeding. MDCT with CT angiography and 3D mapping now offers a valuable option for diagnosis, not only for patients whose colonoscopy findings were negative, but also as a first-line screening modality for patients with active bleeding and hemodynamic instability. This article reviews the valuable role of MDCT in the diagnosis of multiple different causes of rectal bleeding, including rectal vascular malformations, rectal varices, ischemic colitis, stercoral colitis, inflammatory bowel disease, radiation proctopathy, infectious colitis, and rectal cancer.

CT and MR enterography in evaluating small bowel diseases: when to use which modality?

MR and CT techniques optimized for small bowel imaging are playing an increasing role in the evaluation of small bowel disorders. Several studies have shown the advantages of these techniques over traditional barium fluoroscopic examinations due to improvements in spatial and temporal resolution combined with improved bowel distending agents. The preference of MR vs. CT has been geographical and based on expertise and public policy. With the increasing awareness of radiation exposure, there has been a more global interest in implementing techniques that either reduce or eliminate radiation exposure. This is especially important in patients with chronic diseases such as inflammatory bowel disease who may require multiple studies over a lifetime or in studies that require sequential imaging time points such as in assessment of gastrointestinal motility. MRI has many properties that make it well suited to imaging of the small bowel: the lack of ionizing radiation, the improved tissue contrast that can be obtained by using a variety of pulse sequences, and the ability to perform real time functional imaging. Moreover, MR modalities allow visualization of the entire bowel, without overlapping bowel loops, as well as the detection of both intra- and extraluminal abnormalities.The intra- and extraluminal MR findings, combined with contrast enhancement and functional information, help to make an accurate diagnosis and consequently characterize small bowel diseases.

A novel biphasic oral contrast solution for enterographic studies

PURPOSE

To compare the efficacy and patients' tolerance of a new mixed biphasic oral contrast solution with routine biphasic oral contrast agent in magnetic resonance (MR) enterography (MRE).

MATERIALS AND METHODS

Thirty-seven patients (group 1) had MRE with the new mixture, whereas 14 patients (group 2) had MRE with biphasic oral contrast agent (lactulose). Magnetic resonance enterography images were evaluated by 2 experienced radiologists. Each intestinal segment was evaluated for luminal distension (LD), distinction from the surrounding tissue (wall conspicuity), and the confidence of radiologist for evaluation of the specified segment (radiological evaluation confidence). Comparisons between the 2 groups were performed using the Mann-Whitney U test. Interrater and intrarater agreement values were obtained. In addition, patients' acceptability and tolerance were assessed.

RESULTS

The new mixture was more effective than the oral contrast agent used in group 2 for LD, wall conspicuity, and radiological confidence. The values of interrater and intrarater agreement in scoring LD, wall conspicuity, and radiological confidence were generally moderate.

CONCLUSION

Our new mixture allowed good-quality enterographic images, and this solution was well tolerated by patients. In addition, this mixture is useful for evaluation of small bowels and colonic segments. We suggest the use of it for enterographic examinations.

[Radiological diagnostics of the small bowel]

The barium meal with plain X-ray films of the small intestine has for decades been the undisputed gold standard in imaging of the small intestine. More recently, X-rays and fluoroscopy with an overall accuracy of 73% have been replaced by multislice computed tomography (MSCT) or modern magnetic resonance imaging (MRI). Ultrasound is suitable for the orienting investigation of the small intestine in the context of general abdominal sonography as well as for dedicated examinations with a sensitivity of 67-96% and a specificity up to 97%. The endoscopic examinations of the small bowel, such as video capsule endoscopy and double-balloon enteroscopy are expensive and time-consuming techniques, which provide valuable information in special indications. Other than with the stomach or colon, the diagnostics of primary small intestine tumors plays a relatively subordinate role due to the low incidence of 3-5% of all gastrointestinal (GI) neoplasms but with a high sensitivity of 84% and a specificity of up to 97% for computed tomography (CT) and MRI. Predominant questions are those concerning ileus or the diagnostics of passage disturbances after preceding operations, to depict bowel obstructions, adhesions or the involvement of the small bowel in peritoneal carcinomatosis. The sensitivity per lesion in the initial evaluation of Crohn's disease (CD) is 47-68% for capsule endoscopy, 43% for MRI and 21% for CT enterography. In cases of known CD, the sensitivity is 70% for capsule endoscopy and 79% for MRI. A further indication is the evaluation of acute or occult gastrointestinal bleeding.

Use of CT enterography for the diagnosis of lower gastrointestinal bleeding in pediatric patients

Diagnosis of lower gastrointestinal bleeding (LGIB) represents a significant diagnostic and therapeutic challenge for any physician. While CT enterography (CTE) has been applied in adults with occult LGIB, its use in children has been limited to evaluation of Crohn's disease. We reviewed 6 patients ages 4-15 who underwent CTE for LGIB at a tertiary pediatric institution. In sum, CTE appears to be a valuable tool for localizing the source of LGIB prior to surgical or endoscopic intervention. However, rapid lesion identification must be weighed against the increased radiation exposure and patient discomfort due to bowel distention associated with this diagnostic technique.