The American Association for the Surgery of Trauma Organ Injury Scale 2018 update for computed tomography-based grading of renal trauma: a primer for the emergency radiologist

The most widely used trauma injury grading system is the Organ Injury Scale (OIS) by the American Association for the Surgery of Trauma (AAST). The AAST OIS for renal trauma was revised in 2018 to reflect necessary updates based on decades of experience with computed tomography (CT)-based injury diagnosis and, specifically, to better incorporate vascular injuries, which were not comprehensively addressed in the original OIS. In this review article, we describe CT findings of the AAST OIS for the kidney according to the 2018 revision, with an emphasis on real-world application, and highlight important differences from the prior grading scheme. Routine use of this grading system allows for a standardized classification of the range of renal injuries to aid in management, adding value in the imaging care of trauma patients.