Figure 3.

Tumor-related angiogenesis and hypoxia at various stages of liver metastasis development as observed via contrast-agent-free 3D photoacoustic measurements. 3D analyses of endogenous photoacoustic signals of the whole liver using the oxy-hemo protocol (750 and 850 nm wavelengths) for the monitoring of A) total hemoglobin content (HbT) and B) average tissue oxygen saturation (StO₂). Liver sections from 3D ultrasound C) and photoacoustic imaging of D) HbT and E) StO₂. The dotted line represents the ROI used for photoacoustic signal quantifications. n= 3 mice (healthy group), n= 6 mice per group (Early and Advanced); statistical analyses: one-way ANOVA tests were used (*p-value<0.05; **p-value<0.01; ***p-value<0.001; ****p-value<0.0001). Close-up look on F) healthy and G) metastasized tissues after CD31 labelling. Positive coloration is indicated by red arrows. Yellow “H” and “M” mentions refers to healthy and metastatic tissues respectively.