Diagnosis of lower gastrointestinal bleeding by multi-slice CT angiography: A meta-analysis

Delphi consensus statement for the management of delayed post-polypectomy bleeding

Background

Delayed post-polypectomy bleeding (DPPB) is the most common adverse event following colonic polypectomy, yet its management remains highly heterogeneous and lacks standardization. A considerable number of colonoscopies performed for DPPB may be unnecessary and do not result in hemostatic intervention.

Objectives

To develop evidence-based statements to guide clinical decision-making in DPPB.

Design

Multidisciplinary Delphi consensus statement.

Methods

A panel of 29 experts in gastroenterology, hematology, radiology, and surgery was assembled. Through a systematic review of the literature and a modified Delphi process, consensus statements were developed through iterative rounds of anonymous voting. Statements were revised following anonymous voting and feedback at each round. Those achieving 80% agreement were accepted.

Results

The expert panel reached a consensus on 36 statements, covering areas such as antithrombotic management, bowel preparation, colonoscopy indications, and therapeutic hemostatic modalities. Key recommendations include guidance for managing self-limited bleeding and risk stratification to reduce the rate of unnecessary colonoscopies, as well as recommendations for hemodynamically unstable patients who may require primary angioembolization. A practical clinical algorithm is proposed.

Conclusion

This document provides a consensus-based framework for managing DPPB. These recommendations aim to improve patient outcomes and optimize healthcare resources while fostering a standardized approach to this common adverse event.

Iatrogenic pseudoaneurysm after bone biopsy managed with endovascular coil embolisation

Bone marrow biopsy (BMB) is a routinely performed procedure, with the preferred site being the posterior superior iliac crest. Uncommonly, it may be complicated by haemorrhagic complications, especially in patients with coagulopathy. Here, we present a case of pelvic haematoma following a BMB due to the injury of the right internal iliac artery. Endovascular embolisation was performed on an urgent basis to manage this complication. The bleeding stopped following the embolisation.

Emergency medicine updates: Lower gastrointestinal bleeding

INTRODUCTION

Lower gastrointestinal bleeding (LGIB) is a condition commonly seen in the emergency department. Therefore, it is important for emergency medicine clinicians to be aware of the current evidence regarding the diagnosis and management of this disease.

OBJECTIVE

This paper evaluates key evidence-based updates concerning LGIB for the emergency clinician.

DISCUSSION

LGIB is most commonly due to diverticulosis or anorectal disease, though there are a variety of etiologies. The majority of cases resolve spontaneously, but patients can have severe bleeding resulting in hemodynamic instability. Initial evaluation should focus on patient hemodynamics, the severity of bleeding, and differentiating upper gastrointestinal bleeding from LGIB. Factors associated with LGIB include prior history of LGIB, age over 50 years, and presence of blood clots per rectum. Computed tomography angiography is the imaging modality of choice in those with severe bleeding to diagnose the source of bleeding and guide management when embolization is indicated. Among stable patients without severe bleeding, colonoscopy is the recommended modality for diagnosis and management. A transfusion threshold of 7 g/dL hemoglobin is recommended based on recent data and guidelines (8 g/dL in those with myocardial ischemia), though patients with severe bleeding and hemodynamic instability should undergo emergent transfusion. Anticoagulation reversal may be necessary. If bleeding does not resolve, embolization or endoscopic therapies are necessary. There are several risk scores that can predict the risk of adverse outcomes; however, these scores should not replace clinical judgment in determining patient disposition.

CONCLUSIONS

An understanding of literature updates can improve the care of patients with LGIB.

The Role of Imaging for GI Bleeding: ACG and SAR Consensus Recommendations

Gastrointestinal (GI) bleeding is the most common GI diagnosis leading to hospitalization within the United States. Prompt diagnosis and treatment of GI bleeding is critical to improving patient outcomes and reducing high health care utilization and costs. Radiologic techniques including CT angiography, catheter angiography, CT enterography, MR enterography, nuclear medicine red blood cell scan, and technetium-99m pertechnetate scintigraphy (Meckel scan) are frequently used to evaluate patients with GI bleeding and are complementary to GI endoscopy. However, multiple management guidelines exist, which differ in the recommended utilization of these radiologic examinations. This variability can lead to confusion as to how these tests should be used in the evaluation of GI bleeding. In this document, a panel of experts from the American College of Gastroenterology and Society of Abdominal Radiology provide a review of the radiologic examinations used to evaluate for GI bleeding including nomenclature, technique, performance, advantages, and limitations. A comparison of advantages and limitations relative to endoscopic examinations is also included. Finally, consensus statements and recommendations on technical parameters and utilization of radiologic techniques for GI bleeding are provided. © Radiological Society of North America and the American College of Gastroenterology, 2024. Supplemental material is available for this article. This article is being published concurrently in American Journal of Gastroenterology and Radiology. The articles are identical except for minor stylistic and spelling differences in keeping with each journal's style. Citations from either journal can be used when citing this article. See also the editorial by Lockhart in this issue.

Review article: Advances in the management of lower gastrointestinal bleeding

BACKGROUND

Lower gastrointestinal bleeding (LGIB) is a common emergency with substantial associated morbidity and mortality. Elective colonoscopy plays an essential role in management, with an even more important role for radiology in the acute setting. Recent advances in the management of patients with LGIB warrant review as the management has recently evolved.

AIMS

To provide a comprehensive and updated overview of advances in the approach to patients with LGIB METHODS: We performed a comprehensive literature search to examine the current data for this narrative review supplemented by expert opinion.

RESULTS

The incidence of LGIB is increasing worldwide, partly related to an ageing population and the increasing use of antithrombotics. Diverticulosis continues to be the most common aetiology of LGIB. Pre-endoscopic risk stratification tools, especially the Oakland score, can aid appropriate patient triage. Adequate resuscitation continues to form the basis of management, while appropriate management of antithrombotics is crucial to balance the risk of worsening bleeding against increased cardiovascular risk. Radiological imaging plays an essential role in the diagnosis and treatment of acute LGIB, especially among unstable patients. Colonoscopy remains the gold-standard test for the elective management of stable patients.

CONCLUSIONS

The management of LGIB has evolved significantly in recent years, with a shift towards radiological interventions for unstable patients while reserving elective colonoscopy for stable patients. A multidisciplinary approach is essential to optimise the outcomes of patients with LGIB.

The Role of Imaging for Gastrointestinal Bleeding: Consensus Recommendations From the American College of Gastroenterology and Society of Abdominal Radiology

Gastrointestinal (GI) bleeding is the most common GI diagnosis leading to hospitalization within the United States. Prompt diagnosis and treatment of GI bleeding is critical to improving patient outcomes and reducing high healthcare utilization and costs. Radiologic techniques including computed tomography angiography, catheter angiography, computed tomography enterography, magnetic resonance enterography, nuclear medicine red blood cell scan, and technetium-99m pertechnetate scintigraphy (Meckel scan) are frequently used to evaluate patients with GI bleeding and are complementary to GI endoscopy. However, multiple management guidelines exist which differ in the recommended utilization of these radiologic examinations. This variability can lead to confusion as to how these tests should be used in the evaluation of GI bleeding. In this document, a panel of experts from the American College of Gastroenterology and Society of Abdominal Radiology provide a review of the radiologic examinations used to evaluate for GI bleeding including nomenclature, technique, performance, advantages, and limitations. A comparison of advantages and limitations relative to endoscopic examinations is also included. Finally, consensus statements and recommendations on technical parameters and utilization of radiologic techniques for GI bleeding are provided.

Computed Tomography Angiography and Conventional Angiography for the Diagnosis and Treatment of Non-variceal Gastrointestinal Bleeding at a Tertiary Cancer Center

INTRODUCTION

To evaluate the diagnostic value of computed tomography angiography (CTA) and conventional angiography (CA) and the therapeutic value of transarterial embolization for acute gastrointestinal bleeding in patients with malignancy.

METHODS

A retrospective review of 100 patients who underwent CTA and/or CA for gastrointestinal bleeding at a comprehensive cancer center between the years 2011-2021 was performed. Clinical and patient outcome data were collected and analyzed using Kruskal-Wallis tests for continuous variables and chi-square tests or Fisher's exact tests (whichever is appropriate) for categorical variables in univariate analysis. All tests were two-sided at a significance level of 0.05. Analyses were performed using SAS version 9.4 (SAS Institute, Cary, NC).

RESULTS

Fifty-two percent of our patients underwent CTA alone, 29% underwent CA alone, and 19% underwent both procedures. Overall, CTA was positive in 11.3% (8/71) of patients and CA was positive in 22.9% (11/38) of patients. Of patients who underwent both studies, 52.6% (10/19) were positive for both. ICU admission was associated with CTA and/or CA positivity (p=0.015). Of 48 patients with data for embolization, 50% of patients underwent transarterial embolization for bleeding, 11 patients had identifiable bleeding on CA, and 13 patients underwent prophylactic embolization at the site of suspected bleeding. Rebleeding following embolization was found in 33.3% (8/24) of patients, including six patients who underwent prophylactic embolization and two patients who were treated for visualized bleeding.

CONCLUSION

CTA and CA are two critical studies for patients with GI bleeding and a history of malignancy. Neither alone can effectively exclude an identifiable source of bleeding. In patients with a history of malignancy, transarterial embolization may be an effective treatment of both angiographically visible and occult sources of GI bleeding.

The Accuracy of Computed Tomography Angiography Compared With Technetium-99m Labelled Red Blood Cell Scintigraphy for the Diagnosis and Localization of Acute Gastrointestinal Bleeding: A Systematic Review and Meta-Analysis

Imaging tests are commonly used as an initial or early investigation for patients presenting with suspected acute gastrointestinal bleeding (AGIB). However, controversy remains regarding which of two frequently used modalities, computed tomography angiography (CTA) or technetium-99m labelled red blood cell scintigraphy (RBCS), is most accurate. This systematic review and meta-analysis was performed to compare the accuracy of CTA and RBCS for the detection and localization of AGIB. Five electronic databases were searched with additional manual searching of reference lists of relevant publications identified during the search. Two reviewers independently performed screening, data extraction and methodological assessments. Where appropriate, the bivariate model was used for meta-analysis of sensitivities and specificities for the detection of bleeding and Freeman-Tukey double-arcsine transformation used for meta-analysis of proportions of correctly localized bleeding sites. Forty-four unique primary studies were included: twenty-two investigating CTA, seventeen investigating RBCS and five investigating both modalities. Meta-analysis produced similar pooled sensitivities; 0.83 (95% CI 0.74-0.90) and 0.84 (0.68-0.92) for CTA and RBCS respectively. Pooled specificity for CTA was higher than RBCS; 0.90 (0.72-0.97) and 0.84 (0.71-0.91) respectively. However, differences were not statistically significant. CTA was superior to RBCS in correctly localizing bleeding; pooled proportions of 1.00 (0.98-1.00) and 0.90 (0.83-0.96) respectively (statistically significant difference, P < 0.001). There is no evidence that CTA and RBCS have different diagnostic performance with respect to the detection of AGIB. However, CTA is superior to RBCS in terms of correctly localising the bleeding site, supporting usage of CTA over RBCS as the first line imaging investigation.

Management of Patients With Acute Lower Gastrointestinal Bleeding: An Updated ACG Guideline

Acute lower gastrointestinal bleeding (LGIB) is a common reason for hospitalization in the United States and is associated with significant utilization of hospital resources, as well as considerable morbidity and mortality. These revised guidelines implement the Grading of Recommendations, Assessment, Development, and Evaluation methodology to propose recommendations for the use of risk stratification tools, thresholds for red blood cell transfusion, reversal agents for patients on anticoagulants, diagnostic testing including colonoscopy and computed tomography angiography (CTA), endoscopic therapeutic options, and management of antithrombotic medications after hospital discharge. Important changes since the previous iteration of this guideline include recommendations for the use of risk stratification tools to identify patients with LGIB at low risk of a hospital-based intervention, the role for reversal agents in patients with life-threatening LGIB on vitamin K antagonists and direct oral anticoagulants, the increasing role for CTA in patients with severe LGIB, and the management of patients who have a positive CTA. We recommend that most patients requiring inpatient colonoscopy undergo a nonurgent colonoscopy because performing an urgent colonoscopy within 24 hours of presentation has not been shown to improve important clinical outcomes such as rebleeding. Finally, we provide updated recommendations regarding resumption of antiplatelet and anticoagulant medications after cessation of LGIB.

Endovascular management of iatrogenic arterial injury post bone marrow biopsy: A report of 3 cases

Bone marrow biopsy is an important tool for the evaluation of malignant and benign hematologic disorders. Performed blindly, usually with a Jamshidi biopsy needle penetrating the posterior iliac crest bone, the procedure is generally considered safe but rarely complications are observed; vascular complications associated with bleeding are the most serious and potentially life-threatening. We describe 3 cases of arterial injury following a bone marrow biopsy procedure, all treated successfully with minimal invasive endovascular management, and emphasize the need for clinical awareness and recognition of this rare complication in order to facilitate rapid diagnostic and minimal invasive therapeutic interventions, when appropriate, for successful outcomes.

Clinical Predictors of a Positive Ct Angiogram Study Used for the Evaluation of Acute Gastrointestinal Hemorrhage

BACKGROUND

Acute gastrointestinal (GI) bleeding is one of the leading causes of emergency department visits and hospital admissions. CT angiography (CTA) has had an expanding role in the evaluation of acute GI bleeding because it is rapidly performed, widely available, reasonably sensitive and provides precise localization when positive. We attempted to identify patient and clinical characteristics that predict CTA results in order to help guide the utilization of this modality in patients with acute GI bleeding.

METHODS

In this retrospective study, we analyzed all CTAs performed for the evaluation of GI bleeding in the Duke University healthcare system between October 2019 and March 2020. We captured patient characteristics including age, sex, vital signs, hemoglobin, platelets, PT/INR, and anticoagulation status. Study indications were grouped by suspected source of bleeding: upper GI bleeding (hematemesis or coffee-ground emesis) vs small bowel bleeding (melena or "dark stools") vs lower GI bleeding (hematochezia or bright red blood per rectum (BRBPR)). Chi-square, Wilcoxon, t test, and multivariate logistic regression were used to describe and assess the relationship between patient characteristics and study outcomes (Table 1). Table 1 Univariate analysis of patient characteristics by CT angiography outcome Patient Characteristics by Positive CT for GI Bleed No (N = 274) Yes (N = 43) Total (N = 317) p value Gender 0.45¹  Female 138 (50.4%) 19 (44.2%) 157 (49.5%)  Male 136 (49.6%) 24 (55.8%) 160 (50.5%) Age, median (Q1,Q3) 65 (51,75) 70 (62,80) 66 (52, 76)  < 0.01² Heart rate, median (Q1,Q3) 86 (74,100) 89 (72,98) 86 (74, 99) 0.78² MAP, mean (SD) 87.32 (15.52) 81.72 (16.53) 86.56 0.03³ Shock index, median (Q1,Q3) 0.70 (0.58, 0.85) 0.78 (0.55, 1.00) 0.71 (0.58, 0.85) 0.35² Hemoglobin 0.33²  N 273 43 316  Median (Q1, Q3) 8.50 (6.90, 11.00) 7.70 (6.50, 11.30) 8.45 (6.90, 11.00) Baseline hemoglobin 0.20²  N 258 39 297  Median (Q1, Q3) 11.20 (9.40, 13.00) 12.00 (9.40, 14.00) 11.20 (9.40, 13.00) Hemoglobin drop from baseline 0.06²  N 258 39 297  Median (Q1, Q3) 2.10 (0.60, 3.70) 2.70 (1.20, 4.80) 2.20 (0.70, 3.80) Platelets, median (Q1, Q3) 219.5 (141, 301) 183 (139, 246) 217 (139, 282) 0.10² INR 0.27²  N 263 42 305  Median (Q1, Q3) 1.10 (1.00, 1.30) 1.20 (1.00, 1.30) 1.10 (1.00, 1.30) Anticoagulation 0.13¹  No 155 (56.6%) 19 (44.2%) 174 (54.9%)  Yes 119 (43.4%) 24 (55.8%) 143 (45.1%) Upper GI bleeding 0.40¹  No 251 (91.6%) 41 (95.3%) 292 (92.1%)  Yes 23 (8.4%) 2 (4.7%) 25 (7.9%) Small Bowel bleeding 0.76¹  No 216 (78.8%) 33 (76.7%) 249 (78.5%)  Yes 58 (21.2%) 10 (23.3%) 68 (21.5%) Lower GI bleeding 0.09¹  No 134 (48.9%) 15 (34.9%) 149 (47.0%)  Yes 140 (51.1%) 28 (65.1%) 168 (53.0%) ¹Chi-Square ²Wilcoxon ³Equal Variance T-Test RESULTS: A total of 317 patients underwent CTA between October 2019 and March 2020. Forty-three patients (13.6%) had a CTA positive for active bleeding. Multivariable logistic regression showed that after controlling for age, mean arterial pressure (MAP) and indication, only a hemoglobin drop from baseline was significantly associated with a positive CTA. For each 1 g / dL drop in hemoglobin from the patient's baseline, the odds of a positive CT increased by 1.17 (OR 1.17 95% CI 1.00 - 1.36, p = 0.04). Age (OR 1.02 95% CI 0.99 - 1.04, p = 0.06) and hematochezia / BRBPR (OR 2.09 95% CI 0.94-4.64, p = 0.07) approached statistical significance.

CONCLUSIONS

In patients who present to the hospital with GI bleeding, CTA can be a helpful triage tool that is most helpful in older patients with suspected lower GI bleeding with a drop in hemoglobin from baseline. Other clinical factors including MAP and the use of anticoagulants were not predictive of a positive CTA.

Computed tomography angiography and three-dimensional reconstruction of renal arteries in diagnosing the bleedings after mini-percutaneous nephrolithotomy: a single-center experience of 7 years

OBJECTIVE

This study aimed to investigate the role of computed tomography angiography (CTA) and three-dimensional reconstruction of renal arteries in the evaluation of bleeding after mini- percutaneous nephrolithotomy (PCNL).

METHODS

31 consecutive patients with continuous renal hemorrhage after mini-PCNL were enrolled from January 2015 to January 2022. Demographic and clinical data were retrospectively recorded and analyzed. All patients had received CTA evaluation and subsequently digital subtraction angiography (DSA) embolization to manage renal bleeding. CTA and 3D reconstruction of renal arteries were performed using the 320 multi-detector computed tomography technique and the images were evaluated by experienced radiologists. DSA embolization were performed by an interventional radiologist with more than 10 years of experiences.

RESULTS

CTA and 3D construction of renal arteries showed 28 cases of vascular lesions (28/31, 90.3%), including 15 cases of pseudoaneurysm (15/28, 53.6%), 9 cases of arteriovenous fistula (9/28, 32.1%), and 4 cases of suspicious bleeding spot (4/28, 14.3%). While DSA revealed 31 cases of vascular lesions (100%), including 15 cases of pseudoaneurysm (15/31, 48.4%), 10 cases of arteriovenous fistula (10/31, 32.3%), 6 cases of bleeding spot and (6/31, 19.4%). The serum creatinine level was elevated slightly before mini-PCNL and after DSA embolization (73.1±18.1 vs 92.1±33.6, p<0.01). 15 patients (15/31, 48.4%) required blood transfusion, with mean blood transfusion volume of 700±660 ml (range, 400-1800ml). The bleeding was controlled without any further severe complications.

CONCLUSIONS

CTA and 3D reconstruction of renal arteries were safe and effective in diagnosing renal arterial bleedings after mini-PCNL, with a sensitivity of 90.3% and a specificity of 100%.

Gastrointestinal bleeding: imaging and interventions in cancer patients

Gastrointestinal bleeding (GIB) among cancer patients is a major source of morbidity and mortality. Although a wide variety of etiologies contribute to GIB, special considerations should be made for cancer-related factors such as the type of malignancy, location and extent of disease, hemostatic parameters, and treatment effects. Key imaging modalities used to evaluate GIB include computed tomography angiography (CTA), radionuclide imaging, and catheter-based angiography. Understanding the cancer and treatment history and recognizing the associated imaging manifestations are important for identifying the source and potential causes of GIB in cancer patients. This article will review the common clinical presentations, causes, imaging manifestations, and angiographic management of GIB in cancer patients.

Contrast extravasation on computed tomography angiography in patients with hematochezia or melena: Predictive factors and associated outcomes

PURPOSE

The purpose of this study was to identify variables associated with extravasation on computed tomography angiography (CTA) in patients with hematochezia/melena and compare the outcome of patients with extravasation on CTA to those without extravasation.

MATERIAL AND METHODS

Ninety-four patients (51 men, 38 women; mean age, 69 ± 16 [SD] years) who underwent CTA within 30 days of hematochezia/melena were included. Variables associated with extravasation on CTA were searched using univariable and multivariable analyses. Outcomes of patients with visible extravasation on CTA were compared with those without visible extravasation.

RESULTS

One hundred and one CTA examinations were included. Extravasation was observed on 26/101 CTA examinations (26%). At multivariable analysis the need for vasopressor drugs (odds ratio [OR], 7.6; P = 0.040), high transfusion requirements (> 2 blood units) (OR, 7.1; P = 0.014), CTA performed on the day of a hemorrhagic event (OR, 46.2; P = 0.005) and repeat CTA (OR, 27.8; P = 0.011) were independently associated with extravasation on CTA. Extravasation on CTA was followed by a therapeutic procedure in 25/26 CTAs (96%; 26 patients) compared to 13/75 CTAs (17%; 68 patients) on which no extravasation was present (P < 0.001). No patients (0/26; 0%) with contrast extravasation on CTA died while 8 patients (8/61; 13%) without contrast extravasation died, although the difference was not significant (P = 0.099).

CONCLUSION

Extravasation on CTA in the setting of hematochezia or melena is especially seen in clinically unstable patients who receive more than two blood units. Presence of active extravasation on CTA leads to more frequent application of a therapeutic procedure; however, this does not significantly affect patient outcome.

The utility of a dual-phase, dual-energy CT protocol in patients presenting with overt gastrointestinal bleeding

Background

Due to their easy accessibility, CT scans have been increasingly used for investigation of gastrointestinal (GI) bleeding.

Purpose

To estimate the performance of a dual-phase, dual-energy (DE) GI bleed CT protocol in patients with overt GI bleeding in clinical practice and examine the added value of portal phase and DE images.

Materials and Methods

Consecutive patients with GI bleeding underwent a two-phase DE GI bleed CT protocol. Two gastroenterologists established the reference standard. Performance was estimated using clinical CT reports. Three GI radiologists rated confidence in GI bleeding in a subset of 62 examinations, evaluating first mixed kV arterial images, then after examining additional portal venous phase images, and finally after additional DE images (virtual non-contrast and virtual monoenergetic 50 keV images).

Results

52 of 176 patients (29.5%) had GI bleeding by the reference standard. The overall sensitivity, specificity, and positive and negative predictive values of the CT GI bleed protocol for detecting GI bleeding were 65.4%, 89.5%, 72.3%, and 86.0%, respectively. In patients with GI bleeding, diagnostic confidence of readers increased after adding portal phase images to arterial phase images (p = 0.002), without additional benefit from dual energy images. In patients without GI bleeding, confidence in luminal extravasation appropriately decreased after adding portal phase, and subsequently DE images (p = 0.006, p = 0.018).

Conclusion

A two-phase DE GI bleed CT protocol had high specificity and negative predictive value in clinical practice. Portal venous phase images improved diagnostic confidence in comparison to arterial phase images alone. Dual-energy images further improved radiologist confidence in the absence of bleeding.

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.

Empiric cone-beam CT-guided embolization in acute lower gastrointestinal bleeding

OBJECTIVES

To evaluate the clinical effect and safety of cone-beam CT (CBCT)-guided empirical embolization for acute lower gastrointestinal bleeding (LGIB) in patients with a positive CT angiography (CTA) but subsequent negative digital subtraction angiography (DSA).

METHODS

A retrospective study of consecutive LGIB patients with a positive CTA who received a DSA within 24 h from January 2008 to July 2019. Patients with a positive DSA were treated with targeted embolization (TE group). Patients with a negative DSA underwent an empiric CBCT-guided embolization of the assumed ruptured vas rectum (EE group) or no embolization (NE group). Recurrent bleeding, major ischemic complications, and in-hospital mortality were compared by means of Fisher's exact test. Further subgroup analysis was performed on hemodynamic instability.

RESULTS

Eighty-five patients (67.6 years ± 15.7, 52 men) were included (TE group, n = 47; EE group, n = 19; NE group, n = 19). If DSA was positive, technical success of targeted embolization was 100% (47/47). If DSA was negative and the intention to treat by empiric CBCT-guided embolization, technical success was 100% (19/19). Recurrent bleeding rates in the TE group, EE group, and NE group were 17.0% (8/47), 21.1% (4/19), and 52.6% (10/19) respectively. Empiric CBCT-guided embolization reduced rebleeding significantly in patients with a negative DSA and hemodynamic instability (EE group, 3/10 vs NE group, 10/12, p = .027). Major ischemic complications occurred in one patient (TE group). Overall, the in-hospital mortality rate was 7.1% (6/85).

CONCLUSION

Empiric cone-beam CT-guided embolization proved to be a feasible, effective, and safe treatment strategy to reduce rebleeding and improve clinical success in hemodynamically unstable patients with acute LGIB, positive CTA but negative DSA.

KEY POINTS

• A novel transarterial embolization technique guided by cone-beam CT could be developed extending the "empiric" embolization strategy to lower gastrointestinal bleeding. • By implementing the empiric treatment strategy, nearly all patients with an active lower gastrointestinal bleeding on CTA will be eligible for a superselective empiric embolization, even if subsequent catheter angiography is negative. • In patients with a negative catheter angiography, empiric embolization reduces the rebleeding rate and, particularly in hemodynamically unstable patients, improves clinical success compared with a conservative "wait-and-see" management.

CTA measurements of acute lower gastrointestinal bleeding size predict subsequent positive catheter angiography

PURPOSE

The purpose of this study was to determine whether the measured size of active gastrointestinal hemorrhage was useful in predicting subsequent positive findings at catheter angiography.

MATERIALS AND METHODS

This was a single-institution retrospective study consisting of 32 patients with computed tomography angiography (CTA) positive for gastrointestinal bleeding who went on to receive catheter angiography. Each CTA was reviewed, with axial measurements of the anterior-posterior and transverse dimensions of the largest foci of hemorrhage recorded. Volumetric analysis was used to measure the volume of hemorrhage. These measurements were performed for both the arterial and portal venous phases. Additionally, the interval growth between the arterial and portal venous phase was also calculated.

RESULTS

There was a statistically significant difference in the absolute size of the maximum transverse dimension on portal venous phase imaging (mean = 19.8 mm, p < 0.001), as well as an interval increase in transverse (mean = 8.5 mm, p < 0.001) and anteriorposterior (mean = 5.4 mm, p = 0.027) size between arterial and portal venous phases in patients with positive catheter angiography versus negative catheter angiography. There was a statistically significant difference in the volume of hemorrhage on arterial (mean = 1.72 cm³, p = 0.020) and portal venous phases (mean = 5.89 cm³, p = 0.016), as well as an interval change in the size of hemorrhage between the two phases (mean = 4.17 cm³, p = 0.020) in patients with positive catheter angiography versus patients in the negative catheter angiography group.

CONCLUSIONS

The absolute axial size and volume of hemorrhage, as well as the interval change between the arterial and portal venous phases of CTA imaging is predictive of subsequent positive catheter angiography.

The utilization of CTA in management of gastrointestinal bleeding in a tertiary care center ED. Are we using it enough?

BACKGROUND

Gastrointestinal (GI) bleeding is a common patient presentation to the Emergency Department (ED) and the source can be difficult to diagnose.

PROCEDURE

Computed tomography angiography (CTA) is a new but validated modality with high sensitivity and specificity for diagnosis and treatment of GI bleeds, especially in differentiating arterial from venous bleeding. With high reported validity of CTA, some studies have suggested its ability to better triage patients in the ED and impact ED workflow and resource utilization. We evaluated the use of CTA use an academic tertiary care center ED for GI bleeding.

FINDINGS

Retrospective chart review of 1493 patient (2012-2015), one - way ANOVA, and one-tail t-test, found CTA is used significantly less (0.7%) compared to classical endoscopy (75.7%, p < .001), video capsule endoscopy (VCE)(4.8%, p < .001), tagged red blood cell scintigraphy(4.4%, p < .001), and traditional catheter-directed angiography(2.88%, p < .001). In our subset of 11 CTA cases, we found mean time (in hours) to CTA was faster than mean time to endoscopy, 31:47 [95% CI: -7:50-71:24] and 42:44 [95% CI: 18:27-67:01] respectively. The difference in means between time to CTA and time to endoscopy did not achieve statistical significance, 12:57 h [95% CI -18:51-44:45; p = .40].

CONCLUSION

We concluded that in light of its validation against these other diagnostic modalities, CTA may be underutilized in the care of patients with GI bleeding and should be studied further to study its impact on early risk stratification, treatment, and resource utilization.

Society of abdominal radiology gastrointestinal bleeding disease-focused panel consensus recommendations for CTA technical parameters in the evaluation of acute overt gastrointestinal bleeding

PURPOSE

To formulate consensus recommendations for CT angiography technical parameters used to evaluate overt gastrointestinal (GI) bleeding.

METHODS

An electronic questionnaire consisting of 17 questions was sent to a panel of 16 radiologists with expertise on the imaging of GI bleeding from the Society of Abdominal Radiology GI Bleeding disease-focused panel to obtain consensus agreement on issues related to CTA technical parameters for imaging overt GI bleeding. A multi-round Delphi method of voting was performed to obtain consensus which was defined as ≥ 80% agreement.

RESULTS

Consensus agreement was reached in 15/17 (89%) of the questions including the technique for the administration of IV contrast, the number of phases, scan timing, and image reconstruction.

CONCLUSIONS

A panel of experts on the imaging of GI bleeding from the Society of Abdominal Radiology was able to reach consensus on the majority of technical parameters used for CTA of overt GI bleeding. These recommendations should improve the quality of patient care by adopting these minimal technical requirements for optimal exam performance and lead to less variation in the performance of these exams which will facilitate collecting and comparing published data from different centers. These recommendations will need revisions as additional scientific data become available.

Recent use of NSAID and NOAC medications are associated with a positive CT arteriogram

BACKGROUND

Computed tomography angiography (CTA) is a diagnostic modality utilized in patients with suspected active lower gastrointestinal (GI) bleeding. CTA use in clinical practice is limited by the risk of contrast-induced nephropathy, and the loss of patients from direct physician observation while undergoing the test. Identifying clinical predictors of a positive result would be useful in guiding physician utilization of CTA studies.

METHODS

We performed a single-center retrospective study to determine which clinical predictors are associated with a positive CTA. Binary logistical regression modeling was used to identify the independent predictors and the results were expressed as adjusted odds ratios with corresponding 95% CI .

RESULTS

262 patients met inclusion criteria and there were 61 (23.3%) positive CTA exams. In unadjusted analysis those who were CTA positive were more likely to require management in the intensive care unit (85.2% vs. 14.8%, p < 0.01) and being CTA positive was associated with a significantly increased in-hospital mortality (14.8% vs. 4.5%, p < 0.01). The use of a novel oral anticoagulant (NOAC) in the week prior to presentation was associated with a positive CTA after adjustment for confounders (adjusted odds ratio = 3.89; 95% CI 1.05-14.43). Similarly, the use of a non-steroidal anti-inflammatory drug (NSAID) was associated with a positive CTA (OR 2.36; 1.03-5.41). Only 8% of patients experienced contrast-induced nephropathy.

CONCLUSION

Use of either NOACs or NSAIDs in the previous week is independently associated with a positive CTA in the setting of acute lower GI bleeding. CTA exams appear to confer a low risk of contrast-induced nephropathy.

Magnetic Particle Imaging for Highly Sensitive, Quantitative, and Safe in Vivo Gut Bleed Detection in a Murine Model

Gastrointestinal (GI) bleeding causes more than 300 000 hospitalizations per year in the United States. Imaging plays a crucial role in accurately locating the source of the bleed for timely intervention. Magnetic particle imaging (MPI) is an emerging clinically translatable imaging modality that images superparamagnetic iron-oxide (SPIO) tracers with extraordinary contrast and sensitivity. This linearly quantitative modality has zero background tissue signal and zero signal depth attenuation. MPI is also safe: there is zero ionizing radiation exposure to the patient and clinically approved tracers can be used with MPI. In this study, we demonstrate the use of MPI along with long-circulating, PEG-stabilized SPIOs for rapid in vivo detection and quantification of GI bleed. A mouse model genetically predisposed to GI polyp development (ApcMin/+) was used for this study, and heparin was used as an anticoagulant to induce acute GI bleeding. We then injected MPI-tailored, long-circulating SPIOs through the tail vein, and tracked the tracer biodistribution over time using our custom-built high resolution field-free line (FFL) MPI scanner. Dynamic MPI projection images captured tracer accumulation in the lower GI tract with excellent contrast. Quantitative analysis of the MPI images show that the mice experienced GI bleed rates between 1 and 5 μL/min. Although there are currently no human scale MPI systems, and MPI-tailored SPIOs need to undergo further development and evaluation, clinical translation of the technique is achievable. The robust contrast, sensitivity, safety, ability to image anywhere in the body, along with long-circulating SPIOs lends MPI outstanding promise as a clinical diagnostic tool for GI bleeding.