CT diagnosis of renal artery injury caused by blunt abdominal trauma

Controversy exists about the sensitivity of CT in the diagnosis of occlusion of the renal artery or one of its branches after blunt abdominal trauma. We report 10 cases in which contrast-enhanced CT was used to diagnose correctly either main (seven cases) or segmental (three cases) posttraumatic renal artery occlusion. The abnormality was proved angiographically and/or surgically in all cases. CT showed the absence of a nephrogram in the devascularized portion of the kidney in all 10 cases. A pyelogram was not shown on CT in the seven patients in whom the main renal artery was occluded, but was present in the three patients who had segmental arterial lesions. Termination of enhancement within the affected artery (renal artery cutoff sign) was observed in one patient, and a thin, peripheral rim of cortical enhancement in an otherwise unenhanced renal segment (rim sign) was observed in three patients. Retroperitoneal hematoma with renal displacement was present in nine patients. Our experience suggests that the absence of a nephrogram on contrast-enhanced CT scans is a useful sign of main or segmental renal arterial occlusion in patients with blunt abdominal trauma.