Real-time visualization of cortical renal perfusion using laser speckle contrast imaging

H. Maassen, W. Heeman, J. Calon, H. van Goor, H.G.D. Leuvenink, G. van Dam, E.C. Boerma

Thursday 5 march 2020

14:20 - 14:30h at Theaterzaal

Parallel session: Parallel sessie XII – Klinische en Basale abstracts

Background: Determining cortical renal perfusion might give surgeons insight in organ quality during transplantation. However, currently, there is no objective technique to measure renal cortical perfusion. Laser speckle contrast imaging (LSCI) is a fast, full-field, cheap and relatively simple imaging method that can give 2D-perfusion maps of large surfaces. In this study we developed a setup that is capable of visualizing the cortical renal perfusion in real-time with high spatial and temporal resolution on isolated perfused porcine kidneys.

Methods: Slaughterhouse retrieved porcine kidneys were obtained from a local abattoir. The experiments were conducted while the kidneys were on normothermic machine perfusion. The use of LSCI as a perfusion measuring tool was evaluated using flow altering experiments. The change in flow were caused by an increase in temperature, altering pump output, local ischemia as a result of a balloon catheter and by subsequently infusing 4 ml of 100% O_2, air and 100% N₂.

Results: A good agreement is found between the blood flow and LSCI with a change in temperature and pump output. Local ischemia appears directly after use of the balloon catheter with LSCI as can be seen in figure 1. The infusion of all gasses show a decrease in cortical renal perfusion of which the length seems to be determined by the N₂ content. When perfusion restores, LSCI can pick up on local individual high activity active units that initially show up as high perfusion areas (figure 2). The reduced cortical flow areas were not visible at any moment by human inspection which emphasizes the power of LSCI.

Conclusions: LSCI can identify the slightest of changes in cortical renal perfusion with extremely high temporal and spatial resolution in real-time, ahead of human inspection. More research is required to link cortical renal perfusion to organ viability.