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

Importance of communication of CT indication for imaging yield in patients with gastrointestinal bleed

PURPOSE

The indications for requesting a diagnostic test are important for the selection and timing of imaging protocols. We sought to evaluate the diagnostic yield and impact on patient disposition when evaluating computed tomography (CT) of the abdomen and pelvis in adult patients presenting with gastrointestinal bleeding (GIB) to the Emergency Department (ED).

METHODS

This study was an observational cohort study of consecutive adult ED patients with ICD10 codes related to GIB between 5/5/2018 and 6/1/2020. CT reports were reviewed for indications, exam type and findings. Reports were classified as positive (active bleeding, recent bleeding or suspected etiology for GIB), negative or other significant findings. Methodological guidelines for reporting observational studies were followed (STROBE).

RESULTS

Among 943 patients with GIB during the study period, 33% (n = 312) had an abdominopelvic CT ordered. Most CTs included contrast, 64.1% (n = 200) used a single portal venous phase and 28.9% (n = 90) were multi-phase. CT identified active bleeding in 4.2% (n = 13/312) and intraluminal blood in 2.9% (n = 9/312) patients. Patients that had GIB indications on the CT order (n = 142) were more likely to receive a multiphase study compared to those without GIB indication (n = 94) (43.0% vs. 8.5%, difference 34.5%, 95% CI 23.7% to 43.7%, p < 0.0001). Patients that received multiphase studies were more likely to have a source of GIB identified compared to single-phase (18.9% vs 1.5%, OR 15.3, 95% CI 4.4 to 53.7, p < 0.0001). In 40.3% (n = 117/290) of patients without bleeding, an intra-abdominal cause for their symptoms was identified. Those with GIB or with an identified cause were more likely to be admitted.

CONCLUSIONS

One-third of patients evaluated in the ED with GIB had a CT ordered. Active GIB was detected more often when multiphase exams were performed. Multiphase exams are done more often if GIB is listed in the CT indication. When a CT is positive, patients are more likely to be admitted or observed. Accurate indications are critical to optimize exam performance.

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.

Use of "Diagnostic Yield" in Imaging Research Reports: Results from Articles Published in Two General Radiology Journals

OBJECTIVE

"Diagnostic yield," also referred to as the detection rate, is a parameter positioned between diagnostic accuracy and diagnosis-related patient outcomes in research studies that assess diagnostic tests. Unfamiliarity with the term may lead to incorrect usage and delivery of information. Herein, we evaluate the level of proper use of the term "diagnostic yield" and its related parameters in articles published in Radiology and Korean Journal of Radiology (KJR).

MATERIALS AND METHODS

Potentially relevant articles published since 2012 in these journals were identified using MEDLINE and PubMed Central databases. The initial search yielded 239 articles. We evaluated whether the correct definition and study setting of "diagnostic yield" or "detection rate" were used and whether the articles also reported companion parameters for false-positive results. We calculated the proportion of articles that correctly used these parameters and evaluated whether the proportion increased with time (2012-2016 vs. 2017-2022).

RESULTS

Among 39 eligible articles (19 from Radiology and 20 from KJR), 17 (43.6%; 11 from Radiology and 6 from KJR) correctly defined "diagnostic yield" or "detection rate." The remaining 22 articles used "diagnostic yield" or "detection rate" with incorrect meanings such as "diagnostic performance" or "sensitivity." The proportion of correctly used diagnostic terms was higher in the studies published in Radiology than in those published in KJR (57.9% vs. 30.0%). The proportion improved with time in Radiology (33.3% vs. 80.0%), whereas no improvement was observed in KJR over time (33.3% vs. 27.3%). The proportion of studies reporting companion parameters was similar between journals (72.7% vs. 66.7%), and no considerable improvement was observed over time.

CONCLUSION

Overall, a minority of articles accurately used "diagnostic yield" or "detection rate." Incorrect usage of the terms was more frequent without improvement over time in KJR than in Radiology. Therefore, improvements are required in the use and reporting of these parameters.

Interventional Radiology Options after Visceral Surgery

Background

Postoperative management of patients undergoing visceral surgery can present challenging clinical situations with significant morbidity and mortality. Interventional radiological techniques offer quick, safe, and effective minimally invasive treatment options in the postoperative management of visceral surgery.

Summary

Most commonly done procedures include - but are not limited to - fluid or abscess drainage, biliary diversion, bleeding embolization, and re-canalization of a thrombosed vessel. While bleeding from side branches after hepatobiliary and pancreatic surgeries can be managed by coil embolization, the hepatic arterial injury should be managed by stent-graft placement. Hepatic venous complications can require a transhepatic or transjugular approach, whereas the transjugular intrahepatic portosystemic shunt approach has a higher clinical success rate in patients with portal vein thrombosis. Biliary leakages require multidisciplinary management, and interventional radiology can offer an efficient treatment, especially in patients with biliodigestive anastomosis.

Key Messages

Interventional radiology provides a broad spectrum of procedures in the management of patients with recent visceral surgery.

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.

Computed tomography versus lower endoscopy as initial diagnostic method for evaluating patients with hematochezia at emergency room

For acute lower gastrointestinal bleeding (LGIB), lower gastrointestinal endoscopy is the preferred initial diagnostic test. However, it is difficult to perform urgently. Computed tomography (CT) is a convenient alternative.This study aimed to determine the diagnostic performance of CT compared to lower endoscopy as an initial test for evaluating acute LGIB.The medical records of 382 patients who visited our emergency department with hematochezia between January 2012 and January 2017 were retrospectively analyzed. Of them, 112 underwent CT, 65 underwent colonoscopy, and 205 underwent sigmoidoscopy as an initial test. For each method, sensitivity, specificity, positive predictive value, and negative predictive value were calculated upon active bleeding site detection and LGIB etiology diagnosis.The sensitivity, specificity, positive predictive value, and negative predictive value of CT for active bleeding site detection were 85.7%, 100%, 100%, and 96.9%, respectively, while those for identifying the etiology of LGIB were 87.4%, 40.0%, 83.5, and 47.6%, respectively.CT was not inferior to lower endoscopy for active bleeding site detection. Early localization and the exclusion of active bleeding were possible with CT. Etiology was diagnosed with high sensitivity and PPV by CT. Thus, CT can be an alternative initial diagnostic tool for evaluating acute LGIB.

Trauma CT evaluation prior to selective angiography in patients with traumatic injuries: negative predictive power and factors affecting its utility

PURPOSE

To evaluate the predictive power of arterial injury detected on contrast-enhanced CT (trauma CT (tCT)) imaging obtained prior to selective angiography for treatment of patients with traumatic abdominal and pelvic injuries.

MATERIALS AND METHODS

A retrospective chart review was performed of all patients who underwent angiography after undergoing contrast-enhanced CT imaging for the evaluation/treatment of traumatic injuries to the abdomen and pelvis between March 2014 and September 2018. Data collection included demographics, pertinent history and physical findings, CT and angiography findings, treatment information, and outcomes.

RESULTS

Eighty-nine (63 males, mean age = 45.8 ± 20.5 years) patients that were found to have 102 traumatic injuries on tCT and subsequently underwent angiography met inclusion criteria for this study. Sixty-four injuries demonstrated evidence of traumatic vascular injury on initial tCT. A negative tCT was able to predict subsequent negative angiography in 83% of cases (negative predictive power = 83%). The ability of tCT to rule out a positive finding on subsequent angiography was also 83% (sensitivity = 83%). The average systolic blood pressure and hemoglobin concentration at the time of tCT were higher in patients who had positive tCT than in patients with negative tCT (p < 0.05 and p < 0.01, respectively). The average time to angiography was greater in patients whom had subsequent negative angiography than the patients who had subsequent positive angiography (p < 0.05).

CONCLUSION

Contrast-enhanced CT imaging may be able to help stratify patients who may have subsequent negative angiograms. Hemodynamic factors may affect sensitivity of tCT. Shorter time to angiography may increase the chance of identifying the injury on subsequent angiography.

Lower Gastrointestinal Bleeding

Lower gastrointestinal bleeding entails a range of severity and a multitude of options for localization and control of bleeding. With experience in trauma, critical care, endoscopy, and definitive surgical interventions, general surgeons are equipped to manage this condition in various clinical settings. This article examines traditional and emerging options for bleeding localization and control available to general surgeons.

Evaluation and management of lower gastrointestinal bleeding

Lower gastrointestinal bleeding (LGIB) is a common cause of presentation to the emergency department and hospital admissions. The incidence of LGIB increases with age and the most common etiologies are diverticulosis, angiodysplasia, malignancy and anorectal diseases. Foremost modality for evaluation and treatment of LGIB is colonosopy. Other diagnostic tools such as nuclear scintigraphy, computed tomography, angiography and capsule endoscopy are also frequently used in the workup of LGIB. Choice of treatment modality depends on the hemodynamic status of the patient, rate of bleeding, expertise and available resources. We present a comprehensive review of the evaluation and management of LGIB.

Selection and Reporting of Statistical Methods to Assess Reliability of a Diagnostic Test: Conformity to Recommended Methods in a Peer-Reviewed Journal

Objective

To evaluate the frequency and adequacy of statistical analyses in a general radiology journal when reporting a reliability analysis for a diagnostic test.

Materials and Methods

Sixty-three studies of diagnostic test accuracy (DTA) and 36 studies reporting reliability analyses published in the Korean Journal of Radiology between 2012 and 2016 were analyzed. Studies were judged using the methodological guidelines of the Radiological Society of North America-Quantitative Imaging Biomarkers Alliance (RSNA-QIBA), and COnsensus-based Standards for the selection of health Measurement INstruments (COSMIN) initiative. DTA studies were evaluated by nine editorial board members of the journal. Reliability studies were evaluated by study reviewers experienced with reliability analysis.

Results

Thirty-one (49.2%) of the 63 DTA studies did not include a reliability analysis when deemed necessary. Among the 36 reliability studies, proper statistical methods were used in all (5/5) studies dealing with dichotomous/nominal data, 46.7% (7/15) of studies dealing with ordinal data, and 95.2% (20/21) of studies dealing with continuous data. Statistical methods were described in sufficient detail regarding weighted kappa in 28.6% (2/7) of studies and regarding the model and assumptions of intraclass correlation coefficient in 35.3% (6/17) and 29.4% (5/17) of studies, respectively. Reliability parameters were used as if they were agreement parameters in 23.1% (3/13) of studies. Reproducibility and repeatability were used incorrectly in 20% (3/15) of studies.

Conclusion

Greater attention to the importance of reporting reliability, thorough description of the related statistical methods, efforts not to neglect agreement parameters, and better use of relevant terminology is necessary.

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.

Does the Reporting Quality of Diagnostic Test Accuracy Studies, as Defined by STARD 2015, Affect Citation?

Objective

To determine the rate with which diagnostic test accuracy studies that are published in a general radiology journal adhere to the Standards for Reporting of Diagnostic Accuracy Studies (STARD) 2015, and to explore the relationship between adherence rate and citation rate while avoiding confounding by journal factors.

Materials and Methods

All eligible diagnostic test accuracy studies that were published in the Korean Journal of Radiology in 2011–2015 were identified. Five reviewers assessed each article for yes/no compliance with 27 of the 30 STARD 2015 checklist items (items 28, 29, and 30 were excluded). The total STARD score (number of fulfilled STARD items) was calculated. The score of the 15 STARD items that related directly to the Quality Assessment of Diagnostic Accuracy Studies (QUADAS)-2 was also calculated. The number of times each article was cited (as indicated by the Web of Science) after publication until March 2016 and the article exposure time (time in months between publication and March 2016) were extracted.

Results

Sixty-three articles were analyzed. The mean (range) total and QUADAS-2-related STARD scores were 20.0 (14.5–25) and 11.4 (7–15), respectively. The mean citation number was 4 (0–21). Citation number did not associate significantly with either STARD score after accounting for exposure time (total score: correlation coefficient = 0.154, p = 0.232; QUADAS-2-related score: correlation coefficient = 0.143, p = 0.266).

Conclusion

The degree of adherence to STARD 2015 was moderate for this journal, indicating that there is room for improvement. When adjusted for exposure time, the degree of adherence did not affect the citation rate.

Transcatheter Arterial Embolization of Angiographically Visible and Occult Renal Capsular Artery Hemorrhage in 28 Patients

PURPOSE

To evaluate the effectiveness and safety of transcatheter arterial embolization to control bleeding from the renal capsular artery (RCA).

MATERIALS AND METHODS

Embolization was performed in 28 patients (14 men; mean age, 49.7 y). Presence and type of previous invasive procedures, initial presentation, and coagulation profile were reviewed. Any preceding abdominal computed tomography (CT) findings were analyzed. Angiographic findings were categorized as active bleeding, suspicious for bleeding, or no bleeding. Technical and clinical success and clinical outcomes were evaluated. Changes in hemoglobin level and transfusion volume of packed red blood cells (pBRCs) before and after embolization were evaluated with the paired t test and Wilcoxon signed-rank test, respectively.

RESULTS

Technical and clinical success rates of therapeutic embolization for active bleeding (n = 11) were 90.9% and 80%, respectively. One case of technical failure (5.9%) and 3 cases of postembolization bleeding (18.7%) were noted in the prophylactic embolization group in patients with suspicion of bleeding (n = 13) or no bleeding (n = 4). Transient renal insufficiency occurred in 4 patients (14.3%). The average hemoglobin level and volume of transfused pBRCs changed from 8.1 g/dL to 9.9 g/dL and from 871 mL to 543 mL, respectively (P < .05). Extravasation of contrast media or acute hematoma in the right subhepatic or perirenal space on CT was noted in 21 patients (78%).

CONCLUSIONS

Embolization can provide an effective and safe method to control RCA bleeding. Perirenal invasive procedures and signs of active or recent right subhepatic or perirenal hemorrhage should raise the suspicion of an RCA source.