A New Technique for Assessing Renal Transplant Perfusion Preoperatively Using Contrast-Enhanced Ultrasound (CEUS) and Three-Dimensional Ultrasound (3DUS) – A Porcine Model Pilot Study

Abstract

This pilot study aims to assess the viability of using contrast-enhanced ultrasound (CEUS) in renal grafts while they are on hypothermic perfusion machines prior to transplantation. We assessed the vascularity and renal perfusion of machine-perfused porcine kidneys (Maastricht category II) using CEUS. Five kidneys were placed on hypothermic machine perfusion for up to 24 hours after retrieval. The kidneys were then scanned with a low MI contrast-specific preset and a bolus of 0.5 ml of Sonovue contrast agent was administered. Contrast-specific ultrasound images of the kidney were acquired in 2D and 3D. The five kidneys demonstrated variable flow rates on the perfusion machine (10 - 37 ml/min at 30 mmHg). The CEUS technique demonstrated good perfusion and flow patterns, similar to those seen in vivo, in four kidneys. One kidney had patent arteries up to the interlobar region but no contrast filling in the cortex or medulla. Small perfusion defects were seen in two of the perfused kidneys. CEUS appears to be a viable technique for assessing global perfusion and small defects within kidneys prior to transplantation. The flow patterns seen in vitro appear to correspond to those seen in vivo. Further work is required to evaluate the relevance of the flow dynamics measured.