Acute gastrointestinal bleeding

[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.

A Jejunal Dieulafoy Lesion: Rare Case Necessitating Surgical Intervention

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Dieulafoy lesions are aberrant submucosal lesions that, in rare circumstances, can result in massive gastrointestinal bleeding.

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These lesions are particularly rare in the jejunum, thus usual diagnostic and therapeutic modalities such as endoscopy may prove difficult.

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Additional imaging such as angiography or radionuclide scanning can be beneficial in identifying the source of bleeding.

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If advanced endoscopic instruments are unavailable at one’s facility, the surgeon must consider operative intervention for life-saving measures.

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The operative findings and management discussed can guide clinicians unexposed to this disease process when surgical intervention is imminent.

Introduction

Dieulafoy lesions are enlarged atypical submucosal vessels that erode the superimposing epithelium in the absence of a primary ulcer. They occur predominantly in the gastric mucosa; however, cases have been seen throughout the gastrointestinal (GI) tract, and rarely, the jejunum. These lesions can cause massive GI hemorrhage leading to shock.

Case Presentation

We present a healthy 19-year-old male who arrived at our institution’s emergency department with multiple episodes of hematemesis and hematochezia that began earlier that morning. The patient was resuscitated and underwent a computerized tomographic (CT) angiography that did not identify any areas of active extravasation. The patient was then taken for an emergent upper and lower endoscopy that was inconclusive. He was subsequently sent for a tagged red blood cell scan, which demonstrated active bleeding in the proximal jejunum. Shortly thereafter, the patient began to decompensate requiring additional blood products and vasopressors. The decision was made for immediate operative intervention, which identified the bleeding Dieulafoy lesion (confirmed by histopathology) in the jejunum.

Discussion

Dieulafoy lesions are rare with an initial presentation of upper or lower GI bleeding, generally treated with endoscopic intervention. They are predominately found in the stomach or duodenum. When no clear source is identified by endoscopy, further diagnostic testing may be of value. Various imaging modalities exist; however, CT angiography or radionuclide scanning are particularly sensitive and can be beneficial in localizing the bleed when preparing for operative intervention.

Conclusion

With advances in endoscopic techniques, surgical intervention is rarely performed for a Dieulafoy lesion. If endoscopy is unsuccessful, additional imaging can be obtained to localize the source of bleeding. However, in emergent cases, when additional imaging cannot be obtained due to lack of time or resources, adequate resection of the lesion should be performed for complete resolution of the disease process. Based on the case presentation and pathologic findings, this case provides further insight into Dieulafoy lesions and the rare need for surgical management.

Intravenous blood pool activity masquerading as gastrointestinal hemorrhage

Radiolabeled red blood cell (RBC) scintigraphy is a common study to detect and localize gastrointestinal hemorrhage. There are many potential entities that may result in false-positive RBC scintigraphy. Here, we present a case of enlarged feeding vessels of omental carcinomatosis which scintigraphically might be mistaken as intraluminal bowel activity and thus active hemorrhage. This case highlights the importance of reviewing correlative imaging in patients with a large neoplastic burden.

The role of imaging in gastrointestinal bleed

Gastrointestinal (GI) bleed accounts for approximately 20% of emergency visits; 2% of hospital admissions and its incidence has been increasing. In patients where the GI bleed does not stop spontaneously, intervention is required to identify the source of bleeding and stop the hemorrhage. Although identifying the source of bleeding can be challenging due to the vast number of underlying etiologies, radiology plays a vital role in patients where endoscopy and/or medical management fail. Radiology offers both non-invasive and invasive options for the diagnosis as well as management of GI bleeds. Scintigraphy and computed tomography angiography (CTA) are the most important non-invasive imaging tests that can identify presence of and help locate the site of bleeding and are used when the patient is hemodynamically stable. If the patient is hemodynamically unstable, conventional angiography (CA) allows diagnosis of the presence, site of bleeding as well as the means of treating the bleed by embolization. Our review article focuses on the various etiologies of GI bleed, the role of imaging in diagnosis as well as treatment of these patients based on the underlying etiologies, the merits and disadvantages of each of these modalities with emphasis on triaging patients for the most appropriate imaging test to guide the most suitable management.

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.

Imaging Workup of Acute and Occult Lower Gastrointestinal Bleeding

Lower gastrointestinal bleeding is defined as occurring distal to the ligament of Treitz and presents as hematochezia, melena, or with anemia and positive fecal occult blood test. Imaging plays a pivotal role in the localization and treatment of lower gastrointestinal bleeds. Imaging tests in the workup of acute lower gastrointestinal bleeding include computed tomography (CT) angiography, nuclear medicine scintigraphy, and conventional catheter angiography. Catheter angiography can also be used to deliver treatment. Imaging tests in the workup of occult lower gastrointestinal bleeding include CT enterography and nuclear medicine Meckel scan.

Small bowel capsule endoscopy: Indications, results, and clinical benefit in a University environment

Capsule endoscopy (CE) opened a new method for visualization of the small intestine. We here further explore its clinical implications.We retrospectively analyzed the clinical benefit of CE in view of medical history, diagnostics, and therapy. Our patient collective consisted of 203 patients. CE was investigated in the context of bleeding, anemia, abdominal pain, diarrhea, Crohn's disease, and suspected tumors.The study collective consisted of 118 male and 85 female patients with a mean age of 58 years (range 8-90 years). Complete bowel transit took place in 82% of the patients. The diagnostic yield in the detection of obscure gastrointestinal bleeding was 80% and for anemia 78%. Mucosal lesions were the most common finding (43%). Unclear abdominal pain had the lowest diagnostic yield (41%). Ensuing therapeutic interventions were mostly medical (66%), and to a minor extent surgical (4.4%) as well as endoscopic (4%).In conclusion, small intestinal CE is a secure method to clarify small intestinal diseases, especially obscure gastrointestinal bleeding, even in pre-operated patients without stenosis symptoms. Our study emphasizes in a collective of patients with extensive prior diagnostics that due to CE therapeutic measures resulted in 73%.

A Novel Technique to Measure the Intensity of Abnormality on GI Bleeding Scans: Development, Initial Implementation, and Correlation With Conventional Angiography

PURPOSE

Develop a technique to quantify intensity of lower gastrointestinal bleeding (LGIB) on Tc-labeled red blood cell (RBC) scintigraphy, correlate with angiography, and determine the tool's predictive value.

MATERIALS AND METHODS

An IRB-approved, single institution database query of GI bleeding scans performed between January 2013 and December 2015. Reports from all studies and imaging from all positive studies were reviewed. A technique was developed for scan analysis, allowing for calculation of percent increase of activity in the region of interest (ROI, area of bleeding) and ROI in the aorta and liver (controls). Database query determined which patients underwent angiography, and which had positive angiograms. Median ROI percent increase in patients with positive scintigraphy and positive angiography was compared to those with positive scintigraphy and negative angiography.

RESULTS

Of 194 bleeding scans performed during the study period, 71 were positive for active LGIB, 37 had angiography, and 9 had active contrast extravasation. The new tool was used to analyze the 37 cases with positive nuclear scans sent for angiography. Median percent increase in ROI activity was 50% in those with positive scan and positive angiogram and 26.8% in those with positive scan but negative angiogram. Using ROI percent change quartiles, we observed a statistically significant association between percent increase in ROI activity from baseline and the probability of having a positive angiogram (Cochran-Armitage trend test, P = 0.01), such that there are no positive angiogram cases when ROI change was <20% and a majority of the positive angiogram cases (67%) in the highest quartile.

CONCLUSIONS

Utilization of processing protocol to determine percent increase in activity from baseline within ROI of active LGIB on scintigraphy has predictive value in determining which patients will not benefit from conventional angiography.

Correlation Between Findings of Multislice Helical Computed Tomography (CT), Endoscopic Examinations, Endovascular Procedures, and Surgery in Patients with Symptoms of Acute Gastrointestinal Bleeding

Background

Endoscopic methods (gastroscopy and colonoscopy) are considered fundamental for the diagnosis of gastrointestinal bleeding. In recent years, multidetector computed tomography (MDCT) has also gained importance in diagnosing gastrointestinal bleeding, particularly in hemodynamically unstable patients and in cases with suspected lower gastrointestinal tract bleeding. CT can detect both the source and the cause of active gastrointestinal bleeding, thereby expediting treatment initiation.

Material/Methods

The study group consisted of 16 patients with clinical symptoms of gastrointestinal bleeding in whom features of active bleeding were observed on CT. In all patients, bleeding was verified by means of other methods such as endoscopic examinations, endovascular procedures, or surgery.

Results

The bleeding source was identified on CT in all 16 patients. In 14 cases (87.5%), bleeding was confirmed by other methods.

Conclusions

CT is an efficient, fast, and readily available tool for detecting the location of acute gastrointestinal bleeding.

CT angiography for acute gastrointestinal bleeding: what the radiologist needs to know

Acute gastrointestinal (GI) bleeding is a common cause of both emergency department visits and hospitalizations in the USA and can have a high morbidity and mortality if not treated rapidly. Imaging is playing an increasing role in both the diagnosis and management of GI bleeding. In particular, CT angiography (CTA) is a promising initial test for acute GI bleeding as it is universally available, can be performed rapidly and may provide diagnostic information to guide management. The purpose of this review was to provide an overview of the uses of imaging in the diagnosis and management of acute GI bleeding, with a focus on CTA.

Localizing Acute Lower Gastrointestinal Hemorrhage: CT Angiography Versus Tagged RBC Scintigraphy

OBJECTIVE

Lower gastrointestinal hemorrhage is a common cause of hospitalization and has substantial associated morbidity and financial cost. CT angiography (CTA) is emerging as an alternative to (99m)Tc-labeled RBC scintigraphy (RBC scintigraphy) for the localization of acute lower gastrointestinal bleeding (LGIB); however, data on comparative efficacy are scant. The aim of this study was to assess the utility of CTA compared with RBC scintigraphy in the overall evaluation and management of acute LGIB.

MATERIALS AND METHODS

We retrospectively reviewed images from all CTA examinations performed for suspected acute LGIB at our tertiary care hospital from January 2010 through November 2011. The comparison group was determined by retrospective review of twice the number of RBC scintigraphic scans consecutively obtained from June 2008 to November 2011 for the same indication. All CTA and RBC scintigraphic scans were reviewed for accurate localization of the site and source of suspected active LGIB.

RESULTS

In total, 45 CTA and 90 RBC scintigraphic examinations were performed during the study period. Seventeen (38%) CTA scans showed active gastrointestinal bleeding compared with 34 (38%) RBC scintigraphic scans (p = 1.000). However, the site of bleeding was accurately localized on 24 (53%) CTA scans. This proportion was significantly greater than the proportion localized on RBC scintigraphic scans (27 [30%]) (p = 0.008). There were no significant differences between the two groups in average hospital length of stay, blood transfusion requirement, incidence of acute kidney injury, or in-hospital mortality.

CONCLUSION

Both CTA and RBC scintigraphy can be used to identify active bleeding in 38% of cases. However, the site of bleeding is localized with CTA in a significantly higher proportion of studies.

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.

Clinical value of interventional diagnosis and embolization therapy in gastrointestinal hemorrhage

AIM: To assess the clinical value of interventional diagnosis and therapy in gastrointestinal hemorrhage.

METHODS: Twenty-nine patients with gastrointestinal hemorrhage underwent digital subtraction angiography (DSA). When positive signs of bleeding appeared, 16 patients underwent embolization with coils and gel foam after superselective catheterization.

RESULTS: The positive signs were observed in 20 of 29 cases, including direct positive signs in 15 cases and indirect positive signs in 5 cases. Transcatheter arterial embolization was carried out in 16 patients, and successful hemostasis was achieved in 14 cases, with a success rate of 87.5% (14/16). The two failed cases were treated by surgical operation. No rebleeding or intestinal ischaemia was observed in 30 days.

CONCLUSION: Selective angiography and intra-arterial embolization are effective and safe in the diagnosis and therapy of gastrointestinal hemorrhage.

Outcomes of Patients with Left Ventricular Assist Devices Undergoing Mesenteric Angiography for Gastrointestinal Bleeding

PURPOSE

To compare measures of clinical success, such as the need for subsequent intervention and mortality, in patients with left ventricular assist devices (LVADs) undergoing mesenteric angiography for gastrointestinal (GI) bleeding with respect to a control group.

MATERIALS AND METHODS

A retrospective study was conducted on 48 consecutive patients undergoing anticoagulation whose GI bleeding was assessed with angiography between August 2007 and June 2014: 24 patients with LVADs and 24 control patients without LVADs. The χ2 and t tests were used for statistical analysis.

RESULTS

Mean ages were 62.1 years ± 9.6 and 74.5 years ± 11.3 in the LVAD and control groups, respectively. No significant difference was observed in hemodynamic instability, presenting hemoglobin level and International Normalized Ratio, or hemoglobin nadir. Two patients with LVADs (8.3%) and 8 control patients (33.3%) had bleeding detected on angiograms (P = .032). Six embolizations were performed in patients with LVADs and 8 were performed in control patients. Clinical success was achieved in 2 of 6 patients with LVADs (33.3%) and 7 of 8 control patients (87.5%; P = .036). Seven patients with LVADs (29.2%) and 1 control patient (4.5%) underwent repeat angiography within 14 days (P = .020). Seven patients with LVADs (29.2%) and 4 control patients (18.2%) required postprocedural endoscopic or operative intervention as definitive therapy (P = .302). All-cause in-hospital mortality rates were 16.7% in the LVAD group and 4.2% in the control group (P = .032), and the respective all-cause 1-year mortality rates were 33.3% and 9.1% (P = .080).

CONCLUSIONS

A higher rate of clinical failure is observed in patients with LVADs presenting with GI bleeding compared with those without LVADs, with a more frequent need for subsequent endoscopic or surgical intervention.

Modeling lengthy work-ups in gastrointestinal bleeding

Multiple procedures and medical devices are being used in a complex interplay to diagnose and treat gastrointestinal bleeding. The aim of the study was to develop a mathematical model that helps in estimating the average number of procedures to be expected in the general management of gastrointestinal bleeding. The modeling process serves as an example of how mathematical analysis in general can be used to answer unresolved clinical questions, lead to a better understanding of the underlying influences in a disease process, and provide a starting point for future clinical trials. The analysis uses a Markov chain to model the transition probabilities among consecutive interventions used to find and treat a bleeding site. The results show that starting a work-up of gastrointestinal bleeding with an esophagogastroduodenoscopy will lead on average to 2.69 procedures per patient. Of these expected procedures, 1.46 will be esophagogastroduodenoscopies, 0.69 colonoscopies, 0.25 video capsule endoscopies, 0.14 double-balloon enteroscopies, and 0.14 procedures from interventional radiology. Management chains initiated with a colonoscopy result in similar outcomes. Among 10,000 simulated individual patients, the number of procedures varies between 1 and 16 consecutive procedures, with 95% of all patients undergoing 6 procedures or less. The outcomes of the model suggest that the published success rates of endoscopic and radiographic procedures are overly optimistic. The results also point to the need to generate clinical data through future studies that more reliably account for treatment failures and the interchange among various complementary diagnostic modalities.

Nuclear medicine tests for acute gastrointestinal conditions

Acute cholecystitis (AC) and lower-gastrointestinal (GI) bleeding are 2 emergencies commonly encountered in nuclear medicine. Evidence of AC on hepatobiliary scintigraphy (HBS) allows for confident diagnosis and provides support for definitive surgical treatment. Proper patient preparation is essential for HBS including fasting and the use of pharmacologic adjuncts is sometimes required. Pharmacologic adjuncts may also be administered during HBS to shorten the length of the examination and increase its specificity. In the interpretation of HBS, there are several sources of false-positive results to be aware of, most commonly chronic cholecystitis. False-negative results on HBS are usually the result of mistaking another structure, such as a dilated cystic duct, for the gallbladder. Abdominal ultrasound is the appropriate initial test in patients with suspected AC, but HBS is an excellent second tier test for the diagnosis of AC in the work-up of indeterminate cases by sonography. GI bleeding scintigraphy plays an important role in the evaluation and management of patients with acute lower-GI bleeding. Scintigraphy serves to localize sites of active GI bleeding and stratify those patients who would benefit from aggressive treatment (surgery or arteriography) vs those who can be managed medically. Pretest involvement of respective services is critical for successful bleeding site confirmation and therapy by interventional radiology or surgery or both. Single photon emission computed tomography/computed tomography erythrocyte scintigraphy has demonstrated superior accuracy and precision over planar scintigraphy in the diagnosis of acute GI bleeding. Additionally, single photon emission computed tomography/computed tomography scintigraphy of GI bleeding provides useful supplemental anatomical information that benefits patient management.

Incidental detection of a bleeding gastrointestinal stromal tumor on Tc-99m red blood cell scintigraphy

The role of 99m-technetium labeled red blood cell (RBC) scintigraphy in acute gastro-intestinal bleed is well-established. The authors report a case of a bleeding gastrointestinal stromal tumor (GIST) incidentally discovered on Tc-99m RBC scintigraphy.

Multidetector CT angiography in acute gastrointestinal bleeding: why, when, and how

Acute gastrointestinal (GI) bleeding remains an important cause of emergency hospital admissions, with substantial related morbidity and mortality. Bleeding may relate to the upper or lower GI tract, with the dividing anatomic landmark between these two regions being the ligament of Treitz. The widespread availability of endoscopic equipment has had an important effect on the rapid identification and treatment of the bleeding source. However, the choice of upper or lower GI endoscopy is largely dictated by the clinical presentation, which in many cases proves misleading. Furthermore, there remains a large group of patients with negative endoscopic results or failed endoscopy, in whom additional techniques are required to identify the source of GI bleeding. Multidetector computed tomography (CT) with its speed, resolution, multiplanar techniques, and angiographic capabilities allows excellent visualization of both the small and large bowel. Multiphasic multidetector CT allows direct demonstration of bleeding into the bowel and is helpful in the acute setting for visualization of the bleeding source and its characterization. Thus, multidetector CT angiography provides a time-efficient method for directing and planning therapy for patients with acute GI bleeding. The additional information provided by multidetector CT angiography before attempts at therapeutic angiographic procedures leads to faster selective catheterization of bleeding vessels, thereby facilitating embolization. Supplemental material available at http://radiographics.rsna.org/lookup/suppl/doi:10.1148/rg.313105206/-/DC1.

Severe hemoperitoneum after patient self-induced fecal evacuation

An increasing incidence of rectal injuries following patient self-induced harmful acts, aimed to sexual or laxatives porpouses, is a fact reported in literature (El-Ashaal et al., 2008). We herein report a case of severe hemoperitoneum related to a middle and upper rectal third seromuscolar tear caused by a self-induced fecal evacuation by means of an arrow with a covered cork tip. An urgent intestinal diversion by means of a Hartmann's operation was performed. The clinical case is presented in relation to the literature debate, regarding the issue of primary repair or resection and anastomosis versus fecal diversion for penetrating rectal injuries (Fabian, 2002; Cleary et al., 2006; Office of the Surgeon General, 1943; Busic et al., 2002). In conclusion, the importance of avoiding an anastomotic breakdown in a patient undergoing a hemorrhagic shock is highlighted.

Arterial interventions in gastrointestinal bleeding

The diagnosis and management of gastrointestinal (GI) bleeding are complicated. A multitude of pathologic processes results in GI bleeding, and often, the bleeding is intermittent in nature. Of the available diagnostic tools, angiography has been the gold standard. Management of patients requires a multidisciplinary approach involving gastroenterologists, interventional radiologists, and surgeons. Therapeutic arterial interventions include pharmacologic control with the use of intraarterial vasopressin, embolization with temporary and permanent embolizing materials, and catheter-induced vasospasm.

Massive rectal bleeding from acquired jejunal diverticula

Small bowel diverticulosis is an uncommon and often asymptomatic condition that is sporadically observed during radiographic examination or laparotomy. Although it is frequently seen in duodenum, jejunal and ileal locations are very rare. The majority of patients with jejunal diverticula have no symptoms. However, they can present with a number of acute and emergent complications with a high rate of mortality. Bleeding from jejunal diverticula occurs in less than 3% - 8% of patients and often present as fresh rectal haemorrhage. This can confuse the clinician since a bleeding source in colon is far more common. We report a patient with acute massive rectal bleeding. Abdominal CT angiography demonstrated a jejunal diverticulum as the bleeding source and the patient underwent resection of the affected segment. She has since remained free of gastrointestinal bleeding.

Although jejunal diverticulosis is rare, it is an important differential diagnosis for patients with gastrointestinal haemorrhage of unknown origin as it may cause extensive rectal bleeding. Abdominal CT angiography can localize the bleeding source and resection of the affected bowel and primary anastomosis is the treatment of choice.

Usefulness of CT angiography in diagnosing acute gastrointestinal bleeding: A meta-analysis

AIM: To analyze the accuracy of computed tomography (CT) angiography in the diagnosis of acute gastrointestinal (GI) bleeding.

METHODS: The MEDLINE, EMBASE, Cancerlit, Cochrane Library database, Sciencedirect, Springerlink and Scopus, from January 1995 to December 2009, were searched for studies evaluating the accuracy of CT angiography in diagnosing acute GI bleeding. Studies were included if they compared CT angiography to a reference standard of upper GI endoscopy, colonoscopy, angiography or surgery in the diagnosis of acute GI bleeding. Meta-analysis methods were used to pool sensitivity and specificity and to construct summary receiver-operating characteristic.

RESULTS: A total of 9 studies with 198 patients were included in this meta-analysis. Data were used to form 2 × 2 tables. CT angiography showed pooled sensitivity of 89% (95% CI: 82%-94%) and specificity of 85% (95% CI: 74%-92%), without showing significant heterogeneity (χ² = 12.5, P = 0.13) and (χ² = 22.95, P = 0.003), respectively. Summary receiver operating characteristic analysis showed an area under the curve of 0.9297.

CONCLUSION: CT angiography is an accurate, cost-effective tool in the diagnosis of acute GI bleeding and can show the precise location of bleeding, thereby directing further management.

Prospective study comparing multi-detector row CT and endoscopy in acute gastrointestinal bleeding

BACKGROUND

Upper and lower acute gastrointestinal bleeding (AGIB) is associated with high rates of mortality and morbidity. The latest computerized tomography (CT) imaging techniques play an important role in the treatment of this pathology.

METHODS

Twenty-nine patients with severe AGIB (11 upper, 18 lower), all hemodynamically stable, underwent endoscopy followed by a multi-detector row CT (MDCT) scan. Endoscopic and MDCT accuracy for the anatomical localization and etiology of AGIB was assessed, the diagnosis being considered correct when the two procedures were concordant or when the diagnosis was confirmed by angiographic, surgical, or post-mortem findings.

RESULTS

The sensitivity in identifying the site and etiology of bleeding was, respectively, 100% and 90.9% for the MDCT scan, compared with 72.7% and 54.5% for endoscopy in upper AGIB, and 100% and 88.2% for the MDCT scan, compared with 52.9% and 52.9% for endoscopy, in lower AGIB.

CONCLUSIONS

Considering the advantages of MDCT over endoscopy, we propose a new diagnostic algorithm for AGIB.

Significance of scintigraphy for the localization of obscure gastrointestinal bleedings

AIM: To determine the role of scintigraphy in patients with gastrointestinal (GI) bleeding of unknown localization.

METHODS: We performed retrospective analyses on 92 patients receiving scintigraphies from 1993 to 2000 in the University of Regensburg hospital, which were done for localization of GI bleeding as a diagnostic step after an unsuccessful endoscopy. In addition to the scintigraphies, further diagnostic steps such as endoscopy, angiography or operations were performed. In some of the scintigraphies with negative results, a provocation test for bleeding with heparinisation was carried out.

RESULTS: 73% of all scintigraphies showed a positive result. In 4.5% of the positive results, the source was located in the stomach, in 37% the source was the small bowel, in 25% the source was the right colon, in 4.5% the source was the left colon, and in 20% no clear localization was possible. Only 4% of all scintigraphies were false positive. A reliable positive scintigraphy was independent of the age of the examined patient. A provocation test for bleeding with heparin resulted in an additional 46% of positive scintigraphies with a reliable localization in primary negative scintigraphies.

CONCLUSION: Our results show that scintigraphy and scintigraphy with heparin provocation tests are reliable procedures. They enable a reliable localization in about half of the obscure GI-bleeding cases. Scintigraphy is superior to angiography in locating a bleeding. It is shown that even in the age of video capsule endoscopy and double-balloon enteroscopy, scintigraphy provides a reliable and directed localization of GI bleeding and offers carefully targeted guidance for other procedures.

Pediatric Gastrointestinal Nuclear Medicine

General localization of gastrointestinal bleeding through the use of labeled red blood cells may be performed in children, or (99m)Tc-pertechnetate may be used if a Meckel's diverticulum is suspected. As in adults, cholecystitis and biliary leak may be assessed in children via (99m)Tc-IDA derivatives. Gastroesophageal reflux can be evaluated by oral consumption of the child's usual diet labeled with (99m)Tc sulfur colloid. For the scintigraphic determination of pulmonary aspiration, a relatively high concentration of tracer within a drop of liquid is placed beneath the child's tongue followed by dynamic imaging of the respiratory tract. Colonic transit scintigraphy can aid in the identification and therapeutic decision-making in patients with functional fecal retention, the most common cause of chronic constipation in children. (18)F-DOPA positron emission tomography is useful for classifying pancreatic involvement in infantile hyperinsulinism as focal or diffuse, thereby differentiating between patients who should receive curative focal pancreatic resection versus those who should receive medical management. Assessment of protein-losing enteropathy can be conducted scintigraphically and, compared with fecal alpha-1 antitrypsin collection, the scintigraphic method can detect esophageal and gastric protein loss. Also, scintigraphic quantification of protein loss can be performed without the requirement for fecal collection. Intestinal inflammation in children with inflammatory bowel disease can be evaluated using (99m)Tc white blood cells. The scintigraphic method is safe, accurate, well-tolerated by children and complementary to endoscopy in most patients.

Acute Gastrointestinal Bleeding: Emerging Role of Multidetector CT Angiography and Review of Current Imaging Techniques

Acute gastrointestinal bleeding is a common cause of hospitalization, morbidity, and mortality in the United States. The evaluation and treatment of acute gastrointestinal bleeding are complex and often require a multispecialty approach involving gastroenterologists, surgeons, internists, emergency physicians, and radiologists. The multitude of pathologic processes that can result in gastrointestinal bleeding, the length of the gastrointestinal tract, and the often intermittent nature of gastrointestinal bleeding further complicate patient evaluation. In addition, there are multiple imaging modalities and therapeutic interventions that are currently being used in the evaluation and treatment of acute gastrointestinal hemorrhage, each with its own strengths and weaknesses. Initial experience indicates that multidetector computed tomographic angiography is a promising first-line modality for the time-efficient, sensitive, and accurate diagnosis or exclusion of active gastrointestinal hemorrhage and may have a profound impact on the evaluation and subsequent treatment of patients who present with acute gastrointestinal bleeding.

Implications of negative technetium 99m-labeled red blood cell scintigraphy in patients presenting with lower gastrointestinal bleeding

BACKGROUND

Lower gastrointestinal (GI) bleeding frequently recurs after negative technetium 99m-labeled red blood cell (RBC) scintigraphy.

METHODS

Between July 1, 1999 and July 31, 2005, 84 negative (99m)Tc-labeled RBC scintigrams were obtained for acute lower GI bleeding. Medical records were abstracted for age, gender, prior history of lower GI hemorrhage, length of hospitalization, initial hematocrit (Hct) and Hct nadir, transfusion requirements, cause of bleeding, use of anticoagulants and/or antiplatelet medications, and rebleeding episodes.

RESULTS

The overall rate of rebleeding was 27% (n = 23). There were no significant associations between any of the patient variables investigated and rebleeding.

CONCLUSIONS

Despite negative (99m)Tc-labeled RBC scintigraphy, more than 25% of patients experience recurrent lower GI bleeding. Patient age, bleeding source, use of anticoagulant/antiplatelet medications, length of stay, admission Hct, Hct nadir, transfusion requirements, and gender are not predictive of the patients who will rebleed.

Single-Photon Emission Computed Tomography/Computed Tomography in Abdominal Diseases

Single-photon emission computed tomography (SPECT) studies of the abdominal region are established in conventional nuclear medicine because of their easy and large availability, even in the most peripheral hospitals. It is well known that SPECT imaging demonstrates function, rather than anatomy. It is useful in the diagnosis of various disorders because of its ability to detect changes caused by disease before identifiable anatomic correlates and clinical manifestations exist. However, SPECT data frequently need anatomic landmarks to precisely depict the site of a focus of abnormal tracer uptake and the structures containing normal activity; the fusion with morphological studies can furnish an anatomical map to scintigraphic findings. In the past, software-based fusion of independently performed SPECT and CT or magnetic resonance images have been demonstrated to be time consuming and not useful for routine clinical employment. The recent development of dual-modality integrated imaging systems, which provide SPECT and CT images in the same scanning session, with the acquired images co-registered by means of the hardware, has created a new scenario. The first data have been mainly reported in oncology patients and indicate that SPECT/CT is very useful because it is able to provide further information of clinical value in several cases. In SPECT studies of abdominal diseases, hybrid SPECT/CT can play a role in the differential diagnosis of hepatic hemangiomas located near vascular structures, in precisely detecting and localizing active splenic tissue caused by splenosis in splenectomy patients, in providing important information for therapy optimization in patients submitted to hepatic arterial perfusion scintigraphy, in accurately identifying the involved bowel segments in patients with inflammatory bowel diseases, and in correctly localizing the bleeding sites in patients with gastrointestinal bleeding.

A Role for Subtraction Scintigraphy in the Evaluation of Lower Gastrointestinal Bleeding in the Athlete

While lower gastrointestinal haemorrhage (LGIH) in the athlete tends to be self-limiting in the majority of athletes, recurrent symptoms occur in some athletes. It is important to identify the smaller percentage of athletes in whom risks and recurrence are greater because both their general health and athletic performance might benefit from more rigorous clinical evaluation. Technetium-99m red blood cell ((99m)Tc RBC) scintigraphy is a technique for detection and localisation of LGIH and offers a number of significant advantages over other imaging modalities in the evaluation of LGIH. Nonetheless, there are a number of limitations recognised in (99m)Tc RBC scintigraphic evaluation of LGIH. Subtraction scintigraphy in (99m)Tc RBC evaluation of gastrointestinal haemorrhage may offer a tool to overcome limitations of conventional scintigraphy. In essence, subtracting a nominal 'mask' or reference image from all subsequent images provides a mechanism to view only the information contributed by accumulated bleeding, removing potential sources of both false-positive and false-negative findings. While the limitations of procedures available for the evaluation of LGIH are generally prohibitive of effective application in the obscure bleeding associated with athletic performance, adopting subtraction methods in conjunction with conventional (99m)Tc RBC scintigraphy may offer a valuable tool in identification and localisation of bleeding sites. The general health and athletic performance may be enhanced in some athletes when the underlying cause of bleeding can be more appropriately managed.

Differential diagnosis of gastrointestinal bleeding

In this article, we review the many causes of gastrointestinal (GI) bleeding and discuss current strategies for rendering a specific diagnosis. Diagnostic tools considered in this review include: clinical assessment, upper endoscopy, colonoscopy, scintigraphy, and conventional arteriography as well as computed tomography angiography and magnetic resonance angiography. An algorithm for the diagnostic work-up of the patient with GI bleeding is included.

Gastrointestinal Bleeding Diagnosed by Red Blood Cell Scintigraphy in a Patient With Aortic Stenosis: A Case of Heyde Syndrome

The authors report a case of small bowel bleeding diagnosed by Tc-99m-labeled red blood cell (RBC) scintigraphy during the postoperative period after aortic valve replacement. There is a relationship between aortic valve stenosis and gastrointestinal bleeding in elderly patients, called Heyde syndrome. The described patient had chronic anemia that worsened after surgery. RBC scintigraphy localized the source of bleeding from jejunal angiodysplasia confirmed by mesenteric angiography. This case illustrates the diagnostic information provided by RBC scintigraphy in this syndrome.