Contrast‐enhanced sonography of postbiopsy arteriovenous fistulas in kidney grafts

PURPOSE: To assess the usefulness of contrast-enhanced ultrasonography (CE-US) in the visualization of a kidney graft following a biopsy that was complicated by an arteriovenous fistula (AVF). METHODS: Four postrenal transplant patients who had developed AVFs following graft biopsy were examined using standard US and CE-US. Additionally, follow-up examinations were conducted using CE-US, at 4-6 weeks and 10-12 weeks following fistula closure. RESULTS: The fistulas were detected using color Doppler US, Power Doppler US, and B-flow technique. Reduced parenchymal flow was only detected in one case using standard flow visualization techniques. CE-US allowed for the visualization of regions of disturbed parenchymal perfusion that were not visible in the standard examinations. At follow-up, B-mode ultrasound and standard flow examinations appeared normal. However, all contrast-enhanced images showed clearly demarcated residual regions of reduced parenchymal perfusion, in areas where the fistulas had been previously present. CONCLUSIONS: A posttraumatic AVF reduces parenchymal perfusion in the affected region. CE-US examination may help in monitoring fistulas during the active phase and following spontaneous closure.