High Frequency Ultrasound in Monitoring Suitability for Transplantation

Currently there are no validated clinical methods to assess liver preservation injury. In this work we use high frequency ultrasound integrated backscatter (HFUIB) to assess liver damage in different experimental models of liver ischemia. The ultimate goal of this work is to provide a non-invasive tool to assess organ suitability for transplantation. To examine the effects of liver ischemia at different temperatures, livers from Wistar rats are surgically excised, immersed in phosphate buffer saline (PBS) and stored at 4 and 20°C for 24h. To mimic organ preservation, livers are excised, flushed with University of Wisconsin (UW) solution and stored at 4°C for 24h. Preservation injury is simulated by not flushing livers with UW solution. Ultrasound images and corresponding radio frequency data are collected over the ischemic periods. No significant increase in HFUIB is measured for the livers prepared using standard preservation conditions. For all other ischemia models, the HFUIB increases by 4-9 dBr demonstrating kinetics dependent on storage conditions. HFUIB increase is associated with liver tissue injury. The results provide a possible framework for using high frequency imaging to non-invasively assess liver preservation injury.