Renal arteriovenous fistula. A 28-year-old female with a history of renal transplantation recently underwent percutaneous renal biopsy for suspected graft rejection. The patient experienced hematuria the day after the biopsy. Doppler US evaluation of the graft kidney demonstrates aliasing in the lower pole parenchyma suggestive for high velocity disturbed flow. The flow waveform was also suggestive for arterialized venous flow with reduced systolic-diastolic difference. The patient underwent CO2 angiogram with subsequent successful coil embolization