Learning objectives
To describe the CT imaging features of each kidney trauma injury grade using cases and illustrative diagrams as per the recent 2018 organ injury update.
Background
The kidney is the most commonly injured genitourinary organ in the setting of blunt trauma, with angioembolisation and surgical treatments increasingly available, particularly in the setting of higher-grade injuries (1). The use of organ injury grading systems has helped risk stratify trauma patients, and also guide further research, leading to an updated injury scale in 2018 (2).
Several criterion for kidney injury have been revised in the recent grading update, primarily regarding vascular and collecting system injuries (3). This study will discuss the pertinent CT...
Imaging findings OR Procedure details
The updated renal injury scale as per the 2018 revision is as follows (2):
Grade I:
subcapsular hematoma
parenchymal contusion without laceration
Grade II:
non-expanding perirenal hematoma confined to perirenal fascia
parenchymal laceration (depth: ≤1 cm and without urinary extravasation)
Grade III:
parenchymal laceration (depth: >1 cm) without collecting system rupture or urinary extravasation
any injury in the presence of a renal vascular injury (thrombosis, pseudoaneurysm or AV fistula) or active bleeding contained within perirenal fascia
Grade IV:
parenchymal laceration extending into urinary collecting system...
Conclusion
With further familiarity of the updated renal injury grading system, more accurate and efficient imaging interpretation can help mitigate the morbidity and mortality associated with renal injury, with consideration of collecting system and key vascular injuries now included in the CT diagnostic criteria.
References
1. Erlich T, Kitrey ND. Renal trauma: the current best practice. Therapeutic advances in urology. 2018;10(10): 295-303.
2. Kozar R, Crandall M, Shanmuganathan K, Zarzaur B, Coburn M, Cribari C et al. Organ injury scaling 2018 update. Journal of Trauma and Acute Care Surgery. 2018;85(6):1119-1122.
3. Buckley, JC, McAninch JW. Revision of current American Association for the Surgery of Trauma renal injury grading system. Journal of Trauma and Acute Care Surgery. 2011;70(1):35-37.