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AAST Liver Injury Scale

AAST-OIS 2018 revision (Kozar et al.)

Grades hepatic trauma on CT with the 2018 revision of the AAST organ injury scale, including vascular-injury and active-bleeding criteria.

Also searched as: trauma · hepatic · injury grading · CT · hepatic injury · grading

CT findings present (select all that apply)

The highest-grade applicable finding determines the AAST grade.

Multiple separate liver injuries are present

2018 rule: advance one grade for multiple injuries, but not beyond grade III.

Lower concern
No injury findings selected
  • None of the listed findings is present — on this assessment the organ shows no traumatic injury pattern, so no AAST grade applies (grade I is the mildest injury).
  • If any listed finding is present, select it; the single highest-grade criterion determines the AAST grade.

How this tool works

The AAST liver injury scale stratifies hepatic trauma from grade I (small subcapsular hematoma or superficial capsular tear) to grade V (disruption of more than 75% of a lobe or juxtahepatic venous injury). The 2018 revision incorporated vascular findings: a hepatic pseudoaneurysm or arteriovenous fistula, or active bleeding contained within the parenchyma, makes the injury at least grade III, while bleeding that reaches the peritoneum is grade IV; the revision also dropped Couinaud segment counts in favor of percent-of-lobe disruption. The highest applicable finding sets the grade, and multiple separate injuries advance the grade by one, up to grade III.

Clinical questions that use this

Vetting guides that reach for this tool.