Interrater Agreement of CT Grading of Blunt Splenic Injuries: Does the AAST Grading Need to Be Reimagined?

Abstract

Introduction: The Revised Organ Injury Scale (OIS) of the American Association for Surgery of Trauma (AAST) is the most widely accepted classification of splenic trauma. The objective of this study was to evaluate inter-rater agreement for CT grading of blunt splenic injuries. Methods: CT scans in adult patients with splenic injuries at a level 1 trauma centre were independently graded by 5 fellowship trained abdominal radiologists using the AAST OIS for splenic injuries – 2018 revision. The inter-rater agreement for AAST CT injury score, as well as low-grade (IIII) versus high-grade (IV-V) splenic injury was assessed. Disagreement in two key clinical scenarios (no injury versus injury, and high versus low grade) were qualitatively reviewed to identify possible sources of disagreement. Results: A total of 610 examinations were included. The inter-rater absolute agreement was low (Fleiss kappa statistic 0.38, P < 0.001), but improved when comparing agreement between low and high grade injuries (Fleiss kappa statistic of 0.77, P < .001). There were 34 cases (5.6%) of minimum two-rater disagreement about no injury vs injury (AAST grade ≥ I). There were 46 cases (7.5%) of minimum two-rater disagreement of low grade (AAST grade I-III) versus high grade (AAST grade IV-V) injuries. Likely sources of disagreement were interpretation of clefts versus lacerations, peri-splenic fluid versus subcapsular hematoma, application of adding multiple low grade injuries to higher grade injuries, and identification of subtle vascular injuries. Conclusion: There is low absolute agreement in grading of splenic injuries using the existing AAST OIS for splenic injuries.

Delayed Presentation of Severe Blunt Liver Trauma Following a 12-Foot Fall: A Case Report of a Grade 4 Hepatic Injury With a Concurrent Grade 1 Renal Injury

“…This scale provides a standardised method for classifying the severity of liver trauma, guiding treatment decisions, and making prognostic assessments. Table 2 outlines the AAST's CT Criteria for Liver Injury Scale, offering clinicians a systematic approach to evaluating and managing liver injuries based on imaging characteristics [ 11 ].…”

Machine Learning Detection and Characterization of Splenic Injuries on Abdominal Computed Tomography

“…Previous studies have documented poor inter-rater reliability in grading splenic injuries. [10][11][12] Finally, the dataset was unbalanced containing a single grade V splenic injury and grade III injuries dominating the major injury group (54%, n = 21/33). While our study yields promising outcomes there are limitations.…”

“…Each CT examination was independently graded in accordance with the AAST splenic injury scoring scale by 5 blinded fellowship-trained abdominal radiologists using a web-based annotation platform (MD.ai, New York, NY). Due to generally poor interobserver agreement in the grading of splenic injuries [10][11][12] and typical clinical practice patterns, AAST I-III injuries were grouped together as lowgrade injuries while AAST IV and V were considered highgrade injuries. A majority vote was used to determine the AAST injury grade (low vs high) for each CT scan.…”

Invited Commentary: Agreement for Blunt Splenic Injuries Has Room for Improvement

“…The article by Adams-McGavin et al 1 evaluates inter-rater agreement for CT grading of blunt splenic trauma using the Revised Organ Injury Scale (OIS) of the American Association for Surgery of Trauma (AAST). 2 The OIS of the AAST is the most commonly used classification of splenic trauma.…”

“…In patients with multiple splenic injuries, radiologists should classify the injury grade by the highest grade of injury present, and the grade can be upgraded by 1 for multiple injuries up to a grade III. 1 As such, upgrading the splenic trauma grade in the setting of multiple injuries cannot upgrade a low-grade injury (ie, grades I-III), which are often managed conservatively, to a high-grade injury (ie, grades IV-V), which often require intervention. 4,6 This nuanced point, mentioned only briefly in the guidelines, leaves some ambiguity to the wording, and in the absence of case examples can result in inconsistent application of the scoring system, as discussed in more detail in this article.…”