Test characteristics of the 3-view abdominal radiograph series in the diagnosis of intussusception

Yield of abdominal radiographs in children with suspected intussusception; rate of pneumoperitoneum and other abdominal pathology

OBJECTIVES

Ultrasound is the criterion standard imaging modality for the diagnosis of intussusception. However, to our knowledge the utility of abdominal radiographs to concurrently screen for pneumoperitoneum or other abdominal pathology that could have a similar presentation has not been studied. Our institutional protocol requires the performance of AP supine and left lateral decubitus views of the abdomen prior to ultrasound evaluation for intussusception, providing an opportunity to examine the yield of abdominal radiographs in this setting. Our primary objective was to determine the rate of pneumoperitoneum on screening abdominal radiographs in children undergoing evaluation for intussusception. Our secondary objective was to determine the rate that other clinically significant pathology is found on these screening abdominal radiographs.

METHODS

We performed a retrospective chart review of all patients under 6 years of age who had any imaging ordered in our large urban pediatric emergency department to evaluate for suspected intussusception during the calendar years 2018-2020.

RESULTS

1115 patient encounters met our inclusion criteria. Among 1090 who had screening abdominal radiographs, 82 (8%) had findings concerning for intussusception. Of those not concerning for intussusception, 635 (58%) were read as normal, 263 (24%) showed moderate to large stool burden, 107 (10%) showed generalized bowel distention, and 22 (2%) showed abnormal gastric distention. Individually the remainder of all other findings compromised <1% of encounters and included radiopaque foreign body (8), intraabdominal calcification (4), pneumonia/effusion (3), pneumatosis intestinalis, abdominal mass (2), diaphragmatic hernia (1), rib fracture (1), appendicolith (1), feeding tube malposition (1), and bowel wall thickening (1). In one encounter the patient had a bowel perforation with pneumoperitoneum present secondary to ingestion of multiple magnets.

CONCLUSIONS

Our study indicates that radiograph-detected pneumoperitoneum is rare in children with suspected intussusception. Constipation is the most common abnormal finding on screening radiographs. Other findings occur in approximately 15% of total cases, some of which require further workup.

Evidence-Based Diagnostic Test Accuracy of History, Physical Examination, and Imaging for Intussusception: A Systematic Review and Meta-analysis

INTRODUCTION

Intussusception is the most common cause of pediatric small bowel obstruction. Timely and accurate diagnosis may reduce the risk of bowel ischemia. We quantified the diagnostic test accuracy of history, physical examination, abdominal radiographs, and point-of-care ultrasound.

METHOD

We conducted a systematic review for diagnostic test accuracy of history, physical examination, and imaging concerning for intussusception. Our literature search was completed in June 2019. Databases included Medline via Ovid, Embase, Scopus, and Wiley Cochrane Library. We conducted a second review of the literature up to June 2019 for any additional studies. Inclusion criteria were younger than 18 years and presenting to the emergency department for abdominal complaints, consistent with intussusception. We performed data analysis using mada, version 0.5.8. We conducted univariate and bivariate analysis (random effects model) with DerSimonian-Laird and Reitsma model, respectively. QUADAS-2 was used for bias assessment.

RESULTS

The literature search identified 2639 articles, of which 13 primary studies met our inclusion criteria. Abdominal pain, vomiting, and bloody stools had positive likelihood ratios LR(+) between 1 and 2, whereas the negative likelihood ratio, LR(-), ranged between 0.4 and 0.8. Abnormal abdominal radiograph had LR(+) of 2.5 and LR(-) of 0.20, whereas its diagnostic odds ratio was 13. Lastly, point-of-care ultrasound had LR(+) of 19.7 and LR(-) of 0.10. The diagnostic odds ratio was 213.

CONCLUSIONS

History and physical examination had low diagnostic test accuracy. Abdominal radiographs had low diagnostic test accuracy, despite moderate discriminatory characteristics. Point-of-care ultrasound had the highest diagnostic test accuracy to rule in or rule out intussusception.

Comparison of clinicians to radiologists in assessment of abdominal radiographs for suspected intussusception

OBJECTIVES

The objectives of this study were to determine agreement of abdominal radiography (AXR) interpretation and to compare test characteristics, between pediatric emergency medicine (PEM) physicians and pediatric radiologists for evaluation of intussusception.

METHODS

This was a retrospective cohort study of children aged 3 months to 3 years presenting to a pediatric emergency department (ED) between 2007 and 2009. For inclusion, subjects required an ED presentation for suspected intussusception, performance of a 2-view AXR (supine and upright/lateral decubitus views) and abdominal ultrasound performed during the ED visit, and a subsequent criterion-standard measure for intussusception available (contrast enema, operative report, or clinical follow-up). All AXRs were reviewed by 2 blinded PEM physicians and 2 pediatric radiologists. Interrater agreement (κ) for AXR interpretation and diagnostic test characteristics were calculated for comparison.

RESULTS

A total of 286 children were included; intussusception was present in 61 patients (21.3%). Moderate agreement was present between the PEM physicians and radiologists for AXR assessment, with κ = 0.57 (95% confidence interval [CI], 0.47-0.66). Radiologist AXR interpretation had specificity of 86.7% (95% CI, 81.6-90.5), sensitivity of 62.3% (95% CI, 49.8-73.4), positive predictive value of 55.9% (95% CI, 43.3-67.9), and negative predictive value of 89.4% (95% CI, 84.6-93.2). Pediatric emergency medicine physician AXR interpretation had specificity of 68.9% (95% CI, 62.6-74.6), sensitivity of 78.7% (95% CI, 66.9-87.1), positive predictive value of 40.7% (95% CI, 32.2-49.7), and negative predictive value of 92.3% (95% CI, 87.1-95.5).

CONCLUSIONS

Agreement between PEM physicians and pediatric radiologists for evaluation of AXR in suspected intussusception is moderate. Sensitivity and negative predictive value of AXR alone are not sufficiently high overall to exclude intussusception; however, PEM physician interpretation of AXR may possess utility in determining need for abdominal ultrasound in low-risk patients given the high negative predictive value.

Comparison of 2-view abdominal radiographs with ultrasound in children with suspected intussusception

BACKGROUND

The clinical presentation of intussusception is variable; therefore, screening with either abdominal radiography (AXR) or abdominal ultrasound (US) is often used, although the optimal method is not known.

PURPOSE

This study aimed to compare the utility of AXR with that of the US in children with suspected intussusception.

METHODS

Retrospective cohort of children age 3 months to 3 years presenting to a pediatric emergency department (ED) between 2007 and 2009. Inclusion criteria were as follows: (1) presentation to the ED for suspected intussusception and (2) both 2-view AXR and US performed during the ED visit. An AXR was deemed negative for intussusception if air was visualized in the ascending colon on 2 views and transverse colon on the supine view; US results were obtained from the radiologist report at the time of presentation. Criterion standard measures for intussusception were contrast enema, operative report, or follow-up.

RESULTS

A total of 286 children were included, with mean (SD) age 16.1 (9.1) months; 62.2% were male, and 43.7% were African American. Intussusception was present in 61 subjects (21.3%). Abdominal radiography had sensitivity of 62.3% (95% confidence interval [CI], 50.1%-74.5%) and specificity of 86.7% (95% CI, 82.2%-91.1%), whereas US had a sensitivity of 98.4% (95% CI, 95.2%-100.0%) and specificity of 96.4% (95% CI, 94.0%-98.9%). Ultrasound had a greater negative predictive value (99.5%; 95% CI, 98.6%-100.4%) compared with AXR (89.4%; 95% CI, 85.4%-93.5%). Abdominal radiography had a greater false-positive rate (13.3% vs 3.6%) and greater false-negative rate (37.8% vs 1.6%), compared with US.

CONCLUSIONS

Ultrasound is superior to AXR as a screening method for establishing and excluding the diagnosis of intussusception. The poor test characteristics of 2-view AXR suggest that it should not be used as a primary screening method in cases of suspected intussusception.

Intussusception: clinical presentations and imaging characteristics

OBJECTIVE

The objectives of this study were to determine the prevalence of clinical findings associated with intussusception based on age and to evaluate the test characteristics of the presence of air in the ascending colon on abdominal radiographs and the effectiveness of ultrasound in diagnosing intussusception.

METHODS

This was a retrospective cohort study via chart review at a tertiary care center from January 2002 to December 2008. All children, aged 0 to 17 years, were identified with intussusception by International Classification of Diseases, Ninth Revision diagnostic coding. Charts were reviewed for clinical signs and symptoms at presentation, and all diagnostic studies were retrieved. A pediatric radiologist reviewed all films and ultrasounds.

RESULTS

A total of 219 patients were identified with intussusception. One hundred thirty-two (60%) of patients were male; 127 (60%) were younger than 1 year (median, 7 months), 59 (27%) were 13 to 35 months (median, 23 months), and 33 (15%) were 3 years or older (median, 5 years). Children younger than 12 months were more likely to present with emesis, irritability, and guaiac-positive or grossly bloody stools compared with children older than 12 months (P < 0.05). In children older than 12 months, abdominal pain was the most common symptom (>96%). Plain films were performed in 192 children, and of these, 163 (85%) had no air present in the ascending colon. Abdominal ultrasound was performed on 63 patients, with 58 (92%) having findings consistent with intussusception.

CONCLUSIONS

Abdominal pain is the most common complaint in all ages for children presenting with intussusception. In children younger than 12 months, the strongest clinical predictors are emesis, irritability, and blood in the stool. For diagnosing intussusceptions, radiographs of the abdomen performed well, but ultrasound performed better, diagnosing intussusception in 92% of the cases.

Accuracy of plain radiographs to exclude the diagnosis of intussusception

OBJECTIVES

To prospectively determine the test characteristics of the 3-view abdominal radiograph to decrease the likelihood of ileocolic intussusception.

METHODS

We conducted a prospective cross-sectional study of children aged 3 months to 3 years suspected of having intussusception at a children's hospital emergency department. Clinicians obtained supine, prone, and left lateral decubitus radiographs. We determined the presence or absence of intussusception by air enema, ultrasound, operative report, or clinical follow-up. A masked pediatric radiologist reviewed all radiographs. The criteria evaluated were whether air was visualized in the ascending colon on each view and in the transverse colon on the supine view.

RESULTS

Nineteen (14.8%) of 128 patients had intussusception. Using air in the ascending colon on all 3 views as the diagnostic criteria, the test characteristics of the 3-view radiograph were sensitivity, 100% (95% confidence interval [CI], 79.1-100); specificity, 17.4% (95% CI, 11.1-26.1); negative predictive value, 100% (95% CI, 79.1-100); and likelihood ratio of a negative test, 0. When 2 or more of 3 views had air in the ascending colon, sensitivity decreased to 89.5% (95% CI, 75.7-100) and specificity improved to 45.0% (95% CI, 35.6-54.3). Air in the transverse colon had moderate sensitivity, 84.2% (95% CI, 67.8-100), but further improved specificity, 63.3% (95% CI, 54.2-72.4).

CONCLUSIONS

The presence of air in the ascending colon on the 3-view abdominal radiograph can decrease the likelihood of or exclude intussusception. When clinical suspicion is low, the presence of specific criterion on a 3-view abdominal radiograph series may obviate the need for further studies.

Diagnosis and management of pediatric appendicitis, intussusception, and Meckel diverticulum

Three of the most common causes of surgical abdominal pain in pediatric patients include appendicitis, Meckel diverticulum, and intussusception. All 3 can present with right lower quadrant pain, and can lead to significant morbidity and even mortality. Although ultrasound is the preferred method of diagnosis with appendicitis and intussusception, considerable variety exists in the modalities needed in the diagnosis of Meckel diverticulum. This article discusses the pathways to diagnosis, the modes of treatment, and the continued areas of controversy.