Postbiopsy arteriovenous fistula in renal allograft: An ultrasound case study.

Arteriovenous fistula is a well-known but rarely diagnosed complication of percutaneous renal biopsy. On Doppler sonography, these fistulae are characterized by a region of high velocity shifts and random color assignment due to vibrating interfaces in the perivascular tissue. Most of them resolve spontaneously, while larger symptomatic ones need intervention.