Fig. 2

Classification of renal trauma using the American Association for the Surgery of Trauma (AAST) renal injury scale. Arterial and portal venous phase imaging is recommended for evaluation. Clinical or imaging findings suggesting collecting system injury should be followed by a delayed excretory phase to detect urine extravasation. The imaging classification criteria are as follows: grade 1 (A): subcapsular haematoma or contusion, without laceration; grade 2 (B–C): superficial laceration ≤ 1 cm depth not involving the collecting system with no evidence of urine extravasation (B) or perirenal haematoma confined within the perirenal fascia (C); grade 3 (D): laceration > 1 cm not involving the collecting system, vascular injury or active bleeding confined within the perirenal fascia; grade 4 (E): laceration involving the collecting system with urinary extravasation, laceration of the renal pelvis, vascular injury to segmental renal artery or vein, segmental infarctions without associated active bleeding or active bleeding extending beyond the perirenal fascia, grade 5 (F–G): shattered kidney (F), avulsion of renal hilum or laceration of the main renal artery or vein or devascularized kidney (G) [19]