The goal of this study was to demonstrate the potential and fit of Raman microscopy to perform quantitative characterization of atherosclerotic plaque composition, with emphasis on the thin cap fibrous atheroma (TCFA), and the identification of microcalcification inclusions in it. A new microscope, designed to automatically obtain a Raman spectral map of biological tissues, was engineered and constructed. The experimental setup enabled 3D scans of ex vivo artery samples on and below the surface and the presentation of spatial spectral maps that can be related to the specific molecular structure of the sample. Our experimental method enabled nondestructive quantification of minute (10 μm diameter) cellular-level microcalcifications in the cap, and a coarse measurement of their depth in the tissue down to 200 μm below surface. We have demonstrated a new microscopic-spectroscopic approach to the identification of microcalcifications present in the atherosclerotic TCFA complex. Unlike previous diagnostic tools, we could image post-mortem tissues, with simultaneous creation of chemical maps of all chemicals involved, along with emphasis on the detection of the hydroxyapatite content of the tissue. Our ability to identify small hydroxyapatite crystals below surface calls for the development of a catheter version of the system, with prospects for research on the mechanism of acute coronary events, as well as the early detection of endangered patients.
- Atherosclerotic plaque
- Raman microscopy
- Thin cap fibrous atheroma (TCFA)