Abstract:A red-green-blue camera-based imaging method is proposed for estimating spatial maps of concentrations of oxyhemoglobin (C HbO ), deoxyhemoglobin (C HbR ), total hemoglobin (C HbT ), tissue oxygen saturation (StO 2 ), and scattering power (b) in liver tissue. Hemodynamic responses to hepatic ischemia-reperfusion of in vivo rat liver tissues induced by portal triad occlusion were evaluated. Upon portal triad occlusion, this method yielded images of decreased C HbO , C HbT , StO 2 , and b, and increased C HbR followed by a progressive increase in C HbO and StO 2 during reperfusion. Time courses of the changes in C HbO , C HbR , C HbT , and StO 2 over different regions of interest (ROI s ) revealed that ischemia results in an abrupt significant (P<0.05) reduction in C HbO , C HbT , and StO 2 with a simultaneous increase in C HbR compared to the baseline level, indicative of the hemodynamic responses during hepatic ischemiareperfusion. Upon reperfusion, there was a gradual increase in C HbO and StO 2 , and decrease in C HbR . The change in average scattering power b implies the presence of morphological alterations in the cellular and subcellular structures induced by ischemia or anoxia. This study shows the potential of monitoring spatiotemporal changes in hemodynamic parameters and morphological changes in studies of hepatic pathophysiology. 31-39 (1976). 11. O. A. Trowell, "The experimental production of watery vacuolation of the liver," J. Physiol. 105(3), 268-297 (1946). 12. S. Akter, S. Maejima, S. Kawauchi, S. Sato, A. Hinoki, S. Aosasa, J. Yamamoto, and I. Nishidate, "Evaluation of light scattering and absorption properties of in vivo rat liver using a single-reflectance fiber probe during preischemia, ischemia-reperfusion, and postmortem," J. Biomed. Opt. 20(7), 076010 (2015). 13. M. Kretzschmar, A. Krüger, W. Schirrmeister, A. Krüger, and W. Schirrmeister, "Hepatic ischemia-reperfusion syndrome after partial liver resection (LR): hepatic venous oxygen saturation, enzyme pattern, reduced and oxidized glutathione, procalcitonin and interleukin-6," Exp. Toxicol. Pathol. 54(5-6), 423-431 (2003). 14. S. Marubayashi, M. Takenaka, K. Dohi, H. Ezaki, and T. Kawasaki, "Adenine nucleotide metabolism during hepatic ischemia and subsequent blood reflow periods and its relation to organ viability," Transplantation 30(4), 294-296 (1980). 15. W. Kamiike, M. Nakahara, K. Nakao, M. Koseki, T. Nishida, Y. Kawashima, F. Watanabe, and K. Tagawa, "Correlation between cellular ATP level and bile excretion in the rat liver," Transplantation 39(1), 50-55 (1985). 16. J. J. Lemasters, H. Bunzendahl, and R. G. Thurman, "Reperfusion injury to donor livers stored for transplantation," Liver Transpl. Surg. 1(2), 124-138 (1995). 17. J. W. Kupiec-Weglinski and R. W. Busuttil, "Ischemia and reperfusion injury in liver transplantation,"Transplant. Proc. 37(4), 1653-1656 (2005). In vivo label-free quantification of liver microcirculation using dual-modality microscopy," J.
