PEDIATRICS/ORIGINAL RESEARCH

Use of Oral Contrast for Abdominal Computed Tomography in Children With Blunt Torso Trauma Angela M. Ellison, MD, MSc*; Kimberly S. Quayle, MD; Bema Bonsu, MD; Madelyn Garcia, MD; Stephen Blumberg, MD; Alexander Rogers, MD; Sandra L. Wootton-Gorges, MD; Benjamin T. Kerrey, MD; Lawrence J. Cook, PhD; Arthur Cooper, MD, MS; Nathan Kuppermann, MD, MPH; James F. Holmes, MD, MPH; on behalf of the Pediatric Emergency Care Applied Research Network (PECARN)† *Corresponding Author. E-mail: [email protected].

Study objective: We compare test characteristics of abdominal computed tomography (CT) with and without oral contrast for identifying intra-abdominal injuries. Methods: This was a planned subanalysis of a prospective, multicenter study of children (40 mph; lap and shoulder belt Occupant in MVC >40 mph; lap belt only

Yes

>40 mph; unrestrained

CT Results

Intra-abdominal Injury

How Diagnosed

Intervention

Abnormal* Mild grade 1 pancreatic injury Normal Mild grade 1 pancreatic injury

Elevation in pancreatic None enzyme levels Elevation in pancreatic Intravenous fluids enzyme levels

No

Normal

Adrenal gland hematoma

Second CT performed

None

No

Normal

GI tract injury

Laparoscopy

No

Normal

GI tract injury

Laparoscopy

Surgical intervention Intravenous fluids Blood transfusion Surgical intervention Intravenous fluids Intravenous fluids None Surgical intervention Blood transfusion

No

13

Occupant in MVC

4 10 7

Occupant in MVC Occupant in MVC Pedestrian or bicyclist Patient run over struck by moving vehicle Fall from an elevation >10 ft

No No No

Normal Pancreatic injury Normal GI tract injury Abnormal* Liver injury Kidney injury

Second CT performed Laparoscopy Laparoscopy

No

Normal

10

Occupant in MVC

No

Normal

Elevation in pancreatic None enzyme levels Elevation in pancreatic None enzyme levels

8

Object struck abdomen Occupant in MVC Fall from elevation Occupant in MVC

No

Abnormal* Mild grade 1 pancreatic injury Normal Liver injury Normal GI tract injury Grade 1 pancreatic injury Abnormal* Grade 2 or 3 kidney injury

2

4 3 15

Lap and shoulder belt; death in same collision

>40 mph; ejected 3–10 ft

No No

>40 mph; lap belt only

No

Mild grade 1 pancreatic injury Mild grade 1 pancreatic injury

Elevation in pancreatic None enzyme levels Clinical diagnosis None Autopsy None Cystogram and pelvic CT

None

GI, Gastrointestinal; MVC, motor vehicle collision; mph, miles per hour. *Abdominal CT scan did not show a definitive injury, but findings were suggestive of an intra-abdominal injury.

Wide variation in the use of oral contrast across participating sites was observed, with a range of 0% to 100% (median 14.2%), as shown in Table 5. In the multivariable logistic regression model, any degree of abdominal pain (versus none) and peritoneal irritation were found to be significantly associated with oral contrast use (Table E2, available online at http://www. annemergmed.com). When comparing the use of oral contrast across the different grades of gastrointestinal and pancreatic injuries,

we found no significant differences (Table E3, available online at http://www.annemergmed.com). We also compared the use of oral contrast across the different levels of clinical suspicion (Table E4, available online at http://www.annemergmed.com). The largest difference identified between clinician groups in use of oral contrast was in the group of physicians with less than 1% suspicion of intra-abdominal injury as oral contrast was more likely to be used. However, after controlling for oral contrast between sites, the difference became nonsignificant.

Table 4. Test characteristics of CT scan with and without oral contrast for any intra-abdominal injury.* Test Characteristic Sensitivity Positive CT result† Abnormal CT result‡ Specificity Positive CT result Abnormal CT result

Oral Contrast (n[127), %

No Oral Contrast (n[559), %

Differences, %

89.0 (82.2 to 93.8) 99.2 (95.7 to 100.0)

88.2 (85.2 to 90.8) 97.7 (96.1 to 98.8)

0.8 (5.3 to 6.9) 1.5 (0.4 to 3.5)

100.0 (99.6 to 100.0) 84.7 (82.2 to 87.0)

99.9 (99.7 to 100.0) 80.8 (79.4 to 82.1)

0.9 (0.0 to 0.2) 4.0 (1.3 to 6.7)

*95% CIs provided in parentheses. † An abdominal CT result was considered positive if a specific intra-abdominal injury was definitively identified on the CT scan. ‡ An abdominal CT result was considered abnormal if a specific intra-abdominal injury was identified on CT or findings suggestive of intra-abdominal injury were identified.

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Oral Contrast and Abdominal Injury in Children Table 5. Prevalence of oral contrast use across participating sites. Site No.

Patients With Contrast Type Known

No. With Oral Contrast

Percentage With Oral Contrast

95% CI

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20

387 109 545 28 29 124 64 123 200 178 469 99 47 100 330 387 225 256 938 349

387 52 256 13 10 38 14 26 40 32 67 13 6 9 18 13 6 4 5 1

100.0 47.7 47.00 46.4 34.5 30.6 21.9 21.1 20.0 18.0 14.3 13.1 12.8 9.0 5.5 3.4 2.7 1.6 0.5 0.3

38.2–57.2 42.8–51.2 26.7–66.1 16.1–52.9 22.4–38.9 11.5–32.3 13.8–28.5 14.4–25.6 12.3–23.7 11.1–17.5 6.4–19.9 2.9–22.7 3.3–14.7 3.0–7.9 1.6–5.2 0.6–4.8 0.0–3.1 0.1–1.0 0.0–1.0

LIMITATIONS There are several factors that may have limited our ability to detect the true impact of oral contrast in this study. First, our outcome (presence of intra-abdominal injury) was assigned based on the results of the same studied test (abdominal CT scan). This incorporation bias may cause our results to appear more similar than they might actually be. Without independent confirmation, the sensitivity of abdominal CT scans will be near 100% because few children will have surgery or an additional investigation after a normal CT scan result unless they have persistent or recurrent hemodynamic instability or symptoms. We also included both gastrointestinal and solid organ injuries in the definition of intra-abdominal injury, which could bias our results because we expect oral contrast to help identify gastrointestinal injuries but not solid organ injuries. We did not examine the CT scans performed in our study to determine whether adequate opacification of the bowel occurred. Our inability to separate children who did and did not achieve opacification of the small bowel may have biased our results. Given the short period from ED arrival to CT scan, it is doubtful that there was adequate time for small bowel opacification in many cases. Two hundred eighty-nine patients were excluded because of the absence of documentation of oral contrast use, which could bias the study results. However, the excluded population represents only 5% of the total population and had a rate of intra-abdominal injuries similar to that of our study sample. Although our study was conducted prospectively and included many patients across different 112 Annals of Emergency Medicine

institutions, it was observational in design. A randomized controlled trial would result in populations with similar distributions of confounders and risks for intra-abdominal injuries. Spectrum bias may have existed for oral contrast use, given that different institutions, radiologists, and clinicians use different protocols or guidelines. Details of the guidelines or protocols used at each site were not collected because they are outside the scope of this study. In addition, we did not measure interobserver variability in contrast use to determine whether contrast use was more of an institutional or individual practice variant. Finally, we were also unable to determine whether oral contrast impaired imaging of any solid organs in our study, including the kidney, liver, and spleen. DISCUSSION This study compared the test characteristics of abdominal CT scan performed with and without oral contrast for identifying intra-abdominal injuries in children after blunt torso trauma. In this large, prospective, multicenter study, the use of oral contrast for the evaluation of intra-abdominal injury in children after blunt torso trauma had a slightly higher specificity. Otherwise, abdominal CT scans performed with and without oral contrast use had similar test characteristics for identifying gastrointestinal, splenic, liver, and pancreatic injuries. Our findings, with the exception of the slightly higher specificity for diagnosing intra-abdominal injuries, are similar to those of previous studies, which did not identify any benefit to the use of oral contrast for identifying intraabdominal injuries in adults or children during their ED evaluation.11,13-15,18 One retrospective single-center study determined the sensitivity and specificity of CT scans performed without oral contrast for evaluation of gastrointestinal injuries (including injuries to the mesentery) in adults.15 The methods for identifying a gastrointestinal injury were similar to that of our study. Our study yielded a similar sensitivity for gastrointestinal injuries in both the oral contrast (95% versus 95%) and no oral contrast (100% versus 99.6%) groups. The specificities in the oral contrast and no oral contrast groups for gastrointestinal injury, however, were much lower in our study (78% versus 95% and 75% versus 99.6%, respectively). The difference in specificity between the 2 studies is likely due to the differences in definitions of abnormalities on CT scan. We are aware of only 1 randomized controlled trial assessing the benefit of oral contrast in the evaluation of patients with blunt torso trauma.14 The investigators concluded that the addition of oral contrast was unnecessary and delayed the time to CT scanning. The Volume 66, no. 2 : August 2015

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study was limited by its small sample size and low prevalence of gastrointestinal injuries (only 6 patients with such injuries), decreasing the power of the study to detect a clinically important difference between the 2 groups. One study specifically evaluated the use of oral contrast with abdominal CT in 101 children with suspected abdominal injuries, focusing on the test performance of CT for gastrointestinal injury.11 In 62% of patients receiving oral contrast, the contrast did not opacify the small bowel and therefore did not provide any additional information. More important, the retained contrast in the stomach impaired liver imaging in one child and may have been the cause of a documented missed solid organ injury. The study was ultimately limited by its small size because only 2 patients with gastrointestinal injuries underwent abdominal CT with oral contrast (sensitivity¼50%). One additional patient was thought to have had a gastrointestinal rupture because of contrast leakage identified on CT but was not found to have such an injury at laparotomy. The authors concluded that oral contrast was of no benefit in children at risk for gastrointestinal injuries. Data in adult patients suggest that despite an average wait time of 144 minutes after ingestion of the oral contrast before CT, it fails to reach the colon in half of cases and small bowel opacification is considered poor in nearly half of cases.12 Despite the above-mentioned studies, little data exist comparing the test characteristics of CT scan with and without oral contrast for identification of solid organ injuries in children or adults. Our study demonstrated a high sensitivity and specificity for identification of splenic and liver injuries with and without oral contrast. When pancreatic injuries were examined separately, CT specificity for pancreatic injuries was high (99.5% with oral contrast and 99.1% without oral contrast) but the CT sensitivity was poor, regardless of whether oral contrast was used. This poor sensitivity is consistent with that of previous studies performed before the use of multidetector row helical CT scans and remains an imaging challenge because the newer, multidetector CT scanners continue to have poor sensitivity for, and underestimate the severity of, pancreatic injuries.19 Patients considered at high suspicion of pancreatic injuries (severe, epigastric tenderness, or elevated pancreatic enzymes) should be considered for observation in the hospital even if the CT scan result is normal. We found a wide variation in the use of oral contrast across study sites, which likely represents the controversy in its use and is a source of clinical inefficiency. Although small differences in clinical characteristics of patients in the oral contrast and no oral contrast groups exist, the variation in oral contrast use was primarily site dependent. The variation Volume 66, no. 2 : August 2015

Oral Contrast and Abdominal Injury in Children

across sites may reflect differences in the comfort level of the radiologists or surgeons in interpreting abdominal CT scans that are conducted without oral contrast. Future studies should explore radiologists’ and surgeons’ comfort levels with interpreting CT scans without oral contrast. In conclusion, oral contrast is used in a substantial proportion of children undergoing abdominal CT scanning after blunt torso trauma, and its use is highly variable across pediatric hospitals. Similar test characteristics exist between abdominal CT scans performed with and without oral contrast for these patients, suggesting that routine use may be unnecessary and delays obtaining CT scans for children at risk for intra-abdominal injuries. Supervising editor: Steven M. Green, MD Author affiliations: From the Department of Pediatrics, Perelman School of Medicine/Children’s Hospital of Philadelphia, Philadelphia, PA (Ellison); the Department of Pediatrics, Washington University/St. Louis Children’s Hospital, St. Louis, MO (Quayle); the Department of Pediatrics, Rady Children’s Hospital (Bonsu); the Department of Emergency Medicine, University of Rochester, Rochester, NY (Garcia); the Department of Pediatrics, Albert Einstein College of Medicine, Bronx, NY (Blumberg); the Department of Emergency Medicine, University of Michigan, Ann Arbor, MI (Rogers); the Departments of Radiology (WoottonGorges), Emergency Medicine, (Kuppermann, Holmes), Pediatrics (Kuppermann), University of California, Davis School of Medicine, Sacramento, CA; the Division of Emergency Medicine, Cincinnati Children’s Hospital Medical Center, Cincinnati, OH (Kerrey); the Department of Pediatrics, University of Utah and PECARN Data Coordinating Center, Salt Lake City, UT (Cook); and the Department of Surgery, College of Physicians and Surgeons, New York, NY (Cooper). Author contributions: JFH and NK conceived and designed the study. JFH obtained funding for the study. AME, KQ, BB, MG, SB, AR, SLW-G, BK, AC, NK, and JFH obtained data for the study. JFH, NK, and LJC conducted the data analysis. AME, LJC, NK, and JFH interpreted the data. AME drafted the article, and all authors critically revised it. AME takes responsibility for the paper as a whole. Funding and support: By Annals policy, all authors are required to disclose any and all commercial, financial, and other relationships in any way related to the subject of this article as per ICMJE conflict of interest guidelines (see www.icmje.org). The authors have stated that no such relationships exist and provided the following details: This work was supported by a grant from the Centers for Disease Control and Prevention (1 R49CE00100201). The Pediatric Emergency Care Applied Research Network (PECARN) is supported by the Health Resources and Services Administration, Maternal and Child Health Bureau, Emergency Medical Services for Children Program through the following cooperative agreements: U03MC00001, U03MC00003, U03MC00006, U03MC00007, U03MC00008, U03MC22684, and U03MC22685. Publication dates: Received for publication September 26, 2014. Revision received January 8, 2015. Accepted for publication January 13, 2015. Available online March 17, 2015. Annals of Emergency Medicine 113

Oral Contrast and Abdominal Injury in Children Presented at the Pediatric Academic Societies annual meeting, April 2013, Washington, DC; and the Society for Academic Emergency Medicine annual meeting, May 2013, Atlanta, GA.

REFERENCES 1. Holmes JK, Sokolove PE, Brant WE, et al. Identification of children with intra-abdominal injuries after blunt trauma. Ann Emerg Med. 2002;39: 500-509. 2. Donohue JH, Federle MP, Griffiths BG, et al. Computed tomography in the diagnosis of blunt intestinal and mesenteric injuries. J Trauma. 1987;27:11-17. 3. Kileen KL, Shanmuganathan K, Poletti PA, et al. Helical computed tomography of bowel and mesenteric injuries. J Trauma. 2001;51: 26-36. 4. Malhotra AK, Fabian TC, Katsis SB, et al. Blunt bowel and mesenteric injuries: the role of screening computed tomography. J Trauma. 2000;48:991-1000. 5. Breen DJ, Janzen DL, Zwirewich CV, et al. Blunt bowel and mesenteric injuries: diagnostic performance of CT signs. J Comput Assist Tomogr. 1997;21:706-712. 6. Rizzo MJ, Federle MP, Griffiths BG. Bowel and mesenteric injury following blunt abdominal trauma: evaluation with CT. Radiology. 1989;173:143-148. 7. Sherck JP, Oakes DD. Intestinal injuries missed by computed tomography. J Trauma. 1990;30:1-7. 8. Mirvis SE, Gens DR, Shanmuganathan K. Rupture of the bowel after blunt abdominal trauma: diagnosis with CT. AJR Am J Roentgenol. 1992;59:1217-1221. 9. Rieger M, Czermak B, El Attal R, et al. Initial clinical experience with a 64 MDCT whole body scanner in an emergency department: better time management and diagnostic quality? J Trauma. 2009;66:648-657. 10. Clancy TV, Ragozzino MW, Ramshaw D, et al. Oral contrast is not necessary in the evaluation of blunt trauma by CT. Am J Surg. 1993;66:680-685. 11. Shankar KR, Lloyd DA, Kitteringham L, et al. Oral contrast with computed tomography in the evaluation of blunt abdominal trauma in children. Br J Surg. 1999;86:1073-1077. 12. Tsang BD, Panacek EA, Brant WE, et al. Effect of oral contrast administration for abdominal computed tomography in the evaluation of acute blunt trauma. Ann Emerg Med. 1997;30:7-13. 13. Allen TL, Muller MT, Bonk RT, et al. Computed tomographic scanning without oral contrast solution for blunt bowel and mesenteric injuries in abdominal trauma. J Trauma. 2004;56:314-322. 14. Stafford RE, McGonigal MD, Weigelt JA, et al. Oral contrast solution and computed tomography for blunt abdominal trauma. Arch Surg. 1999;134:662-667. 15. Stuhlfaut JW, Soto JA, Lucey BC, et al. Blunt abdominal trauma: performance of CT without oral contrast material. Radiology. 2004;233:689-694. 16. Holmes JF, Lillis K, Monroe D, et al. Identifying children at low risk of clinically important blunt abdominal trauma. Ann Emerg Med. 2013;62:107-116. 17. Moore EE, Cogbill TH, Malangoni MA, et al. Organ injury scaling II: pancreas, duodenum, small bowel, colon and rectum. J Trauma. 1990;30:1427-1429. 18. Holmes JF, Offerman SR, Chang CH, et al. Performance of helical CT tomography without oral contrast for the detection of gastrointestinal injuries. Ann Emerg Med. 2004;43:120-128. 19. Phelan HA, Velmahos GC, Jurkovich GJ, et al. An evaluation of multidetector computed tomography in detecting pancreatic injury: results of a multicenter AAST study. J Trauma. 2009;66:641-646.

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APPENDIX. Participating centers and site investigators are listed below in alphabetical order: Bellevue Hospital Center (M. Tunik); Children’s Hospital Boston (L. Lee); Children’s Hospital of Michigan (P. Mahajan); Children’s Hospital of New York–Presbyterian (M. Kwok); Children’s Hospital of Philadelphia (A. Ellison); Children’s National Medical Center (S. Atabaki); Cincinnati Children’s Hospital Medical Center (B. Kerrey); DeVos Children’s Hospital (J. Kooistra); Howard County Medical Center (D. Monroe); Hurley Medical Center (D. Borgialli); Jacobi Medical Center (S. Blumberg); Medical College of Wisconsin/Children’s Hospital of Wisconsin (K. Yen); Nationwide Children’s Hospital (B. Bonsu); University of California Davis Medical Center (J. Holmes, N. Kuppermann); University of Maryland (J. Menaker); University of Michigan (A. Rogers); University of Rochester (M. Garcia); University of Utah/Primary Children’s Medical Center (K. Adelgais); Washington University/St. Louis Children’s Hospital (K. Quayle); Women and Children’s Hospital of Buffalo (K. Lillis). PECARN Steering Committee: N. Kuppermann, Chair; E. Alpern, D. Borgialli, J. Callahan, J. Chamberlain, P. Dayan, J. M. Dean, M. Gerardi, M. Gorelick, J. Hoyle, E. Jacobs, D. Jaffe, R. Lichenstein, K. Lillis, P. Mahajan, R. Maio, D. Monroe, R. Ruddy, R. Stanley, M. Tunik, A. Walker. Maternal and Child Health Bureau/Emergency Medical Services for Children liaisons: D. Kavanaugh, H. Park. Data Coordinating Center (DCC): J. M. Dean, R. Holubkov, S. Knight, A. Donaldson, S. Zuspan Feasibility and Budget Subcommittee (FAB): T. Singh, Chair; A. Drongowski, L. Fukushima, E. Kim, D. Monroe, G. O’Gara, H. Rincon, M. Tunik, S. Zuspan Grants and Publications Subcommittee (GAPS): M. Gorelick, Chair; E. Alpern, D. Borgialli, K. Brown, L. Cimpello, A. Donaldson, G. Foltin, F. Moler, S. Teach Protocol Concept Review and Development Subcommittee (PCRADS): D. Jaffe, Chair; J. Chamberlain, A. Cooper, P. Dayan, J. M. Dean, R. Holubkov, P. Mahajan, R. Maio, N. C. Mann, K. Shaw, A. Walker Quality Assurance Subcommittee (QAS): R. Stanley, Chair; P. Ehrlich, R. Enriquez, M. Gerardi, R. Holubkov, E. Jacobs, R. Lichenstein, K. Lillis, B. Millar, R. Ruddy, M. Shults Safety and Regulatory Affairs Subcommittee (SRAS): W. Schalick, J. Callahan, Cochairs; S. Atabaki, J. Burr, K. Call, J. Hoyle, R. Ruddy, J. Suhajda, N. Schamban

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Table E1. Test characteristics of CT scans with and without oral contrast for gastrointestinal, splenic, liver, and pancreatic injuries. Injury Gastrointestinal injuries* Sensitivity Specificity Splenic injuries Sensitivity Specificity Liver injuries Sensitivity Specificity Pancreatic injuries Sensitivity Specificity

Oral Contrast (n[1,010) (%: 95% CI) n¼16 16/16 (100.0: 79.4–100.0) 780/994 (78.5: 75.8–81.0) n¼55 55/55 (100.0: 93.5–100.0) 955/955 (100.0: 99.6–100.0) n¼41 40/41 (97.6: 87.1–99.9) 969/969 (100.0: 99.6–100.0) n¼6 3/6 (50.0: 11.8–88.2) 999/1,004 (99.5: 98.8–99.8)

No Oral Contrast (n[3,977) (%: 95% CI) n¼87 83/87 (95.4: 88.6–98.7) 2,919/3,890 (75.0: 73.7–76.4) n¼212 206/212 (97.2: 93.9–99.0) 3,764/3,765 (100.0: 99.9–100.0) n¼216 210/216 (97.2: 94.1–99.0) 3,758/3,761 (99.9: 99.8–100.0) n¼36 23/36 (63.9: 46.2–79.2) 3,905/3,941 (99.1: 98.7–99.4)

*Injury to the hollow viscous or associated mesentery from the stomach to the rectum.

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Oral Contrast and Abdominal Injury in Children Table E2. Regression model identifying the associations of clinical findings with the use of oral contrast. Variable Abdominal pain (ref[no pain) Mild Moderate Severe Vomiting GCS score¼14 or 15 Decreased breath sounds Abdominal trauma Seatbelt sign Thoracic trauma Abdominal tenderness (ref[no tenderness) Mild Moderate Severe Peritoneal irritation Abdominal distention Age-adjusted hypotension Age

OR

95% CI

1.6 1.5 1.7 1.1 1.3 1.0 0.9 0.9 1.1

1.3–2.1 1.2–1.8 1.3–2.2 0.8–1.5 0.9–2.0 0.8–1.4 0.8–1.1 0.7–1.1 1.0–1.2

1.0 1.2 0.8 1.6 0.7 0.8 1.0

0.8–1.1 1.0–1.4 0.6–1.1 1.1–2.2 0.5–1.0 0.6–1.2 1.0–1.0

OR, odds ratio; GCS, Glasgow Coma Scale.

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Table E3. Distribution of oral contrast use across different grades of gastrointestinal and pancreatic injuries. Injury

Oral Contrast (%) No Oral Contrast (%)

Gastrointestinal injury grade I II III IV V

n¼16 7 (53.8) 4 (30.8) 1 (7.7) 0 1 (7.7)

Not graded Pancreatic injury grade I–II III–V

3 n¼6 1 (33.3) 2 (66.7)

Not graded

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3

n¼87 35 (50.7) 9 (13.0) 11 (15.9) 1 (1.4) 13 (18.8) P¼.52 18 n¼36 19 (79.2) 5 (20.8) P¼.15 12

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Oral Contrast and Abdominal Injury in Children Table E4. Distribution of oral contrast use by clinician suspicion for intra-abdominal injury.* Clinician suspicion, % 50 Missing suspicion

Oral Contrast (n[1,010) (%) 305 363 161 120 42

(30.8) (36.6) (16.3) (12.1) (4.2) 19

No Oral Contrast (n[3,977) (%) 838 (21.2) 1,518 (38.4) 813 (20.6) 559 (14.1) 224 (5.7) P

Use of Oral Contrast for Abdominal Computed Tomography in Children With Blunt Torso Trauma.

We compare test characteristics of abdominal computed tomography (CT) with and without oral contrast for identifying intra-abdominal injuries...
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