Color Doppler ultrasound for detection of renal arteriovenous fistulas

Abstract

Renal arteriovenous (AV) fistula is uncommon, but sometimes causes severe hematuria. To assess the value of color Doppler ultrasound (CD-US) for the detection of renal AV fistula, we retrospectively reviewed our experience with this disease. Between 1994 and 2001, five patients with renal AV fistula were diagnosed in our institution. Post-biopsy AV fistula of the transplanted kidney was found in 1 patient. Renal AV fistula was detected in 2 patients who presented with gross hematuria. In the remaining 2 patients, renal AV fistula was discovered incidentally during abdominal ultrasonography. We evaluated gray-scale and CD-US imaging in those five patients. In all 5 patients, CD-US showed a whirling flow pattern within an echo-free structure suggesting AV fistula. However, it was difficult to distinguish AV fistula from aneurysm using only CD-US. While pulsed spectral Doppler evaluation of the lesion might be helpful, prompt venous filling on dynamic CT scan and/or renal arteriography was the most definitive sign for diagnosing the renal AV fistula. CD-US is excellent for demonstrating turbulent blood flow signals within the kidney. However, another radiographic study is required to give a definite diagnosis of renal AV fistula. Due to its low cost, low risk and wide availability, we recommend that CD-US be the first-line imaging procedure for the evaluation of hematuria and renal cystic lesion as well as for followup for renal AV fistula.