Only Moderate Intra- and Inter-observer Agreement between Radiologists and Surgeons when Grading Blunt Paediatric Hepatic Injury on CT Scan

Abstract

Introduction: The American Pediatric Surgical Association developed guidelines for the management of haemodynamically stable children with hepatic or splenic injury, based on grade of injury on CT scan. This study investigated the intra- and inter-observer agreement of radiologists, paediatric surgeons, trauma surgeons and hepatobiliary surgeons when scoring liver injury based on CT scan findings.

Patients and Methods: CT scans of patients with blunt abdominal trauma were independently assessed twice by a fellow and a consultant radiologist, paediatric surgeon, trauma surgeon and one consultant hepatobiliary surgeon. Reviewers were unaware of the clinical course. All scans were multislice CTs with a slice thickness of 3 mm, and both the arterial and venous phase were assessed. Injury was scored using the American Association for the Surgery of Trauma (AAST) liver injury scale. Intra-observer agreement was tested using Cohen's kappa coefficient. Inter-observer agreement was tested using Cohen's kappa for the second reading of individual observers and Spearman's rank correlation for the mean of both readings from each observer.

Results: CT scans of 27 patients (11 girls and 16 boys, median age 11.7±5.2 years) were reviewed. Mean AAST grade of liver injury was 3.3±1.1 for radiologists, 2.9±1.0 for paediatric surgeons, 3.0±0.9 for trauma surgeons and 3.2±0.8 for the hepatobiliary surgeon (p=0.30) Intra-observer agreement was moderate, with kappa below 0.7 for all observers except for one of the radiologists. Inter-observer correlation using Cohen's kappa coefficient was also moderate, with kappa below 0.5. In contrast, inter-observer correlation using Spearman's test was good, suggesting that there is agreement on the general severity of injury but not on the exact grading of injury using the AAST scoring system.

Conclusion: Intra-observer agreement is only moderate when assessing liver injury using the AAST grading system. Only the most experienced radiologist demonstrated good intra-observer agreement which might indicate the necessity of the presence of a senior trauma radiologist at all times. However, this is not possible in most centres. Although there was agreement concerning the general severity of injury, inter-observer agreement is also moderate. These data cast doubt on the use of the AAST liver injury score alone as a decision-making tool when assessing haemodynamically stable children with blunt hepatic injury.

liver trauma - CT scan - inter-observer variation

References

• 1 Stylianos S. Evidence-based guidelines for resource utilization in children with isolated spleen or liver injury.  J Pediatr Surg. 2000;  35 164-167
• 2 Croce MA, Fabian TC, Kudsk KA. et al . AAST organ injury scale: Correlation of CT-graded liver injuries and operative findings.  J Trauma. 1991;  31 806-812
• 3 Stylianos S. Compliance with evidence-based guidelines in children with isolated spleen or liver injury: A prospective study.  J Pediatr Surg. 2002;  37 453-456
• 4 Moore EE, Shackford SR, Pachter HL. et al . Organ injury scaling: Spleen, liver, and kidney.  J Trauma. 1989;  29 1664-1666
• 5 St Peter SD, Keckler SJ, Troy L. et al . Justification for an abbreviated protocol in the management of blunt spleen and liver injury in children.  J Pediatric Surg. 2008;  43 191-194
• 6 McVay MR, Kokoska ER, Jackson RJ. et al . Throwing out the “grade” book: Management of isolated spleen and liver injury based on hemodynamic status.  J Pediatr Surg. 2008;  436 1072-1076
• 7 Marmery H, Shanmuganathan K, Alexander MT. et al . Optimization of selection for nonoperative management of blunt splenic injury: Comparison of MDCT grading systems.  AJR Am J Roentgenol. 2007;  1896 1421-1427
• 8 Bee TK, Croce MA, Miller PR. et al . Failures of splenic nonoperative management: Is the glass half empty or half full?.  J Trauma. 2001;  502 230-236
• 9 Ochsner MG. Factors of failure for nonoperative management of blunt liver and splenic injuries.  World J Surg. 2001;  2511 1393-1396
• 10 Fang JF, Wong YC, Lin BC. et al . The CT risk factors for the need of operative treatment in initially hemodynamically stable patients after blunt hepatic trauma.  J Trauma. 2006;  613 547-553
• 11 Fang JF, Chen RJ, Wong YC. et al . Classification and treatment of pooling of contrast material on computed tomographic scan of blunt hepatic trauma.  J Trauma. 2000;  49 1083-1088
• 12 MacLean AA, Durso A, Cohn SM. et al . A clinically relevant liver injury grading system by CT: Preliminary report.  Emerg Radiol. 2005;  12 34-37

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