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

Abstract

for the early recognition of vulnerable plaques. Established clinical techniques provide valuable morphological information but cannot deliver information about the chemical composition of individual plaques. Therefore, spectroscopic imaging techniques have recently drawn considerable attention. Based on the spectroscopic properties of the individual plaque components, as for instance di®erent types of lipids, the composition of atherosclerotic plaques can be analyzed qualitatively as well as quantitatively. Here, we compare the feasibility of multimodal nonlinear imaging combining two-photon°uorescence (TPF), coherent anti-Stokes Raman scattering (CARS) and second-harmonic generation (SHG) microscopy to contrast composition and morphology of lipid deposits against the surrounding matrix of connective tissue with di®raction limited 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 for in vivo application.

Detection and characterization of early plaque formations by Raman probe spectroscopy and optical coherence tomography: an in vivo study on a rabbit model

“…27 Previous results showed depositions dominated by cholesterol and cholesterol esters, but also revealed accumulations of triglycerides. 18,28 Generally, the animals did not show the expected amounts of plaque formations. The presented results were obtained by inserting the Raman probe first, followed by the OCT imaging pullbacks.…”

“…11,12,29,30 TPEF is often combined with other multiphoton processes, such as second harmonic generation and coherent anti-Stokes Raman scattering imaging, a much faster, but also more complicated variant of Raman spectroscopy. 28,[31][32][33] However, for these multimodal techniques, reliable optical fibers that are applicable for imaging still need to be developed.…”

Multimodal Medical Image Fusion in Cardiovascular Applications

“…They mention the possibility to understand vessel anatomy from CT Coronary Angiography including the degree of stenosis on a PET or SPECT scan [39]. For plaque detection and characterization non-invasive (MRI and X-ray angiography) and invasive diagnostic modalities (IVUS and OCT) are used [40]. In terms of plaque rupture prediction fused PET/CT data is utilised to observe metabolic activities in plaques.…”

Improved label‐free diagnostics and pathological assessment of atherosclerotic plaques through nonlinear microscopy

“…In fact, specific contrast between collagen fiber bundles—which are highly concentrated in the fibrous cap—and other molecules (such as lipids) can be generated using NLO imaging by taking advantage of the signal provided by tissue endogenous fluorophores. Moreover, the combination of different NLO techniques in a multimodal scheme allows obtaining both morphological information (similarly to standard histopathological methods) and molecular information on the examined tissue . Such morpho‐functional approach represents a powerful tool for tissue characterization and pathology assessment.…”