
SHG Imaging of Collagen and Application to Fibrosis Quantization 359
tissues. Indeed, inammation has been shown to correspond to an increase of the endogenous uo-
rescence of the tissue. It is presumably due to a strong metabolic activity of the cells involved in the
inammatory response. An example is displayed in Figure 15.2a: we observe many circular structures
that exhibit a strong 2PEF signal and are less present in control lungs. ese round cells have been
shown to correspond to macrophages using immunochemical labeling (Pena etal. 2007). Combined
SHG/2PEF microscopy therefore enables the discrimination of two major pathological processes, ...