Real-time visualization of renal microperfusion using laser speckle contrast imaging

Abstract.

Significance: Intraoperative parameters of renal cortical microperfusion (RCM) have been associated with postoperative ischemia/reperfusion injury. Laser speckle contrast imaging (LSCI) could provide valuable information in this regard with the advantage over the current standard of care of being a non-contact and full-field imaging technique.

Aim: Our study aims to validate the use of LSCI for the visualization of RCM on ex vivo perfused human-sized porcine kidneys in various models of hemodynamic changes.

Approach: A comparison was made between three renal perfusion measures: LSCI, the total arterial renal blood flow (RBF), and sidestream dark-field (SDF) imaging in different settings of ischemia/reperfusion.

Results: LSCI showed a good correlation with RBF for the reperfusion experiment ( $0.94\pm 0.02$ ; $p<0.0001$ ) and short- and long-lasting local ischemia ( $0.90\pm 0.03$ ; $p<0.0001$ and $0.81\pm 0.08$ ; $p<0.0001$ , respectively). The correlation decreased for low flow situations due to RBF redistribution. The correlation between LSCI and SDF ( $0.81\pm 0.10$ ; $p<0.0001$ ) showed superiority over RBF ( $0.54\pm 0.22$ ; $p<0.0001$ ).

Conclusions: LSCI is capable of imaging RCM with high spatial and temporal resolutions. It can instantaneously detect local perfusion deficits, which is not possible with the current standard of care. Further development of LSCI in transplant surgery could help with clinical decision making.