Multimodal nonlinear imaging of atherosclerotic plaques differentiation of triglyceride and cholesterol deposits

Cardiovascular diseases in general and atherothrombosis as the most common of its individualdisease entities is the leading cause of death in the developed countries.Therefore,visualizationand characterization of inner arterial plaque composition is of vital diagnostic interest,especilly for the early recognition of vulnerable plaques.Established clinical techniques provide valuablemorphological information but cannot deliver information about the chemicai composition ofindividual plaques.Therefore,spectroscopic imaging techniques have recently drawn consider-able attention.Based on the spectroscopic properties of the individual plaque components,as forinstance diferent types of lipids,the composition of atherosclerotic plaques can be analyzedqualitatively as well as quantitatively.Here,we compare the feasibility of multimodal nonlinearimaging combining,two-photon fluorescence(TPF),coherent anti-Stokes Raman scatering(CARS)and second-hamonic generation(SHG)microscopy to contrast composition and mor-phology of lipid deposits against the surrounding matrix of connective tissue with diffractionlimited spatial resolution.In this contribution,the spatial distribution of major constituents of the arterial wall and atherosclerotic plaques like elastin,collagen,triglycerides and cholesterol can be simultaneously visualized by a combination of nonlinear imaging methods,providing a powerful label-free complement to standard histopathological methods with great potential forin vivo application.