Traumatic renal laceration (grade II-III of AAST) appearing as linear or wedge-shaped opacification defects that are particularly evident in the nephrographic phase, may have a depth < 1 cm (grade II)  or > 1 cm (grade III) without involvement of the collecting system; in most cases there is associated perirenal hematoma, a hyperattenuating fluid in the perinephric fat.