According to various studies, the incidence of post biopsy arteriovenous fistulae range from 5- 10%. AV fistulae do not have any specific gray scale ultrasound diagnostic features. Color and pulsed Doppler features are characteristic. The region of the fistula has a high velocity blood flow which causes turbulence on color Doppler resulting in perivascular focal tissue vibration. This is demonstrated as a mosaic color pattern. Due to the anomalous connection with the vein, spectral analysis shows an abnormal low resistance arterial waveform with higher diastolic flow velocities. The venous flow pattern will also demonstrate an abnormal arterialized waveform due to increased flow in the vein. Also, 3D ultrasound angiography is emerging as an equally effective modality as MR angiography to demonstrate the exact location of the fistula and its orientation with respect to the other vascular structures.

Most of the studies conducted report spontaneous closure of these vessel abnormalities; however, a few cases may need angiography and embolization or surgical repair. It is suggested that post percutaneous needle biopsy in allograft kidneys periodical color Doppler of the allograft should be performed to detect asymptomatic pseudoaneurysms and AV fistulae. Most of these can then be simply followed up, unless the discussed complications supervene.