[Diagnostic imaging of renal pedicle injury]

We reviewed the radiological findings of 8 patients with renal pedicle injury admitted to our emergency center from January 1986 through September 1995 and compared them with the previously reported findings. The patients included 3 with renal artery occlusion and 5 with avulsion or disruption of renal pedicle vasculature. Extended retroperitoneal hematoma such as contralateral pararenal or central parahilar hematoma was visualized in all 5 cases with avulsion or disruption of renal pedicle vasculature. Although lack of contrast enhancement of injured renal parenchyma is a hall-mark of renal pedicle injury, three cases did not demonstrate this typical finding. In these three cases, one showed partial and the others showed total enhancement of the injured renal parenchyma on contrast enhanced CT. Partial enhancement in one case was found to represent total occlusion of the main renal artery and an intact accessory polar branch on angiography. The other two cases showed total enhancement of the renal parenchyma, with renal vein perforation done and complete disruption of the main renal artery and vein in the other. The latter findings were thought to be due to the maintenance of vascular flow surrounded by hematoma. In conclusion, when central parahilar hematoma is identified, the possibility of renal pedicle injury should be considered even if the renal parenchyma is well enhanced.