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8 February 2008 Optical mechanisms for detection of lipid-rich atherosclerotic plaques by near-infrared spectroscopy
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InfraReDx has developed a spectroscopic cardiac catheter system capable of acquiring near-infrared (NIR) reflectance spectra from coronary arteries in vivo for identification of lipid-rich plaques of interest (LRP). The spectral data are analyzed with a chemometric model, producing a hyperspectral image (a chemogram) used to identify LRP in the interrogated region. In this paper, we describe a FT-IR microscopy system for measurement of the NIR scattering and absorption properties of healthy and diseased regions of human coronary arteries in small volumes (~10 μl). Scattering and absorption coefficients are obtained from sequential 140 um x 140 um regions of interest across the face of 500-micron thick, saline-irrigated fresh coronary artery sections. A customized FTIR microscope, measurement protocol, and inversion algorithm are used for optical property determination, and the system is calibrated using measurements of tissue-simulating phantoms having well-characterized optical properties. Tissue optical properties are co-registered with brightfield transmission images as well as with stained histologic thin sections (H&E, Movat Pentachrome, and Oil Red O) acquired from an immediately-adjacent section. The ultimate goal of these experiments is to establish a mechanistic link between the multivariate model predictions displayed on the InfraReDx chemogram and the light-tissue interactions that govern the measured NIR reflectance spectra.
© (2008) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Edward L. Hull, Craig M. Gardner, James E. Muller M.D., Vianna J. Muller, Christopher V. Salvato, Jennifer B. Lisauskas, and Jay D. Caplan "Optical mechanisms for detection of lipid-rich atherosclerotic plaques by near-infrared spectroscopy", Proc. SPIE 6842, Photonic Therapeutics and Diagnostics IV, 68422A (8 February 2008);

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