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Journal of Biomedical Optics • Open Access

Shear flow-induced optical inhomogeneity of blood assessed in vivo and in vitro by spectral domain optical coherence tomography in the 1.3 μm wavelength range
Author(s): Peter Cimalla; Julia Walther; Matthaeus Mittasch; Edmund Koch

Paper Abstract

The optical inhomogeneity of flowing blood, which appears as a waisted double fan-shaped intensity pattern inside vessels in cross-sectional optical coherence tomography (OCT) images, was investigated for the first time. High resolution spectral domain OCT in the 1.3 μm wavelength region is used to assess this inhomogeneous intravascular backscattering of light in an in vivo mouse model and flow phantom measurements. Based on a predicted alignment of the red blood cells toward laminar shear flow, an angular modulation of the corresponding backscattering cross-section inside the vessels is assumed. In combination with the signal attenuation in depth by absorption and scattering, a simple model of the intravascular intensity modulation is derived. The suitability of the model is successfully demonstrated in the in vivo experiments and confirmed by the in vitro measurements. The observed effect appears in flowing blood only and shows a strong dependency on the shear rate. In conclusion, the shear-induced red blood cell alignment in conjunction with the vessel geometry is responsible for the observed intensity distribution. This inherent effect of blood imaging has to be considered in attenuation measurements performed with OCT. Furthermore, the analysis of the intravascular intensity pattern might be useful to evaluate flow characteristics.

Paper Details

Date Published: 1 November 2011
PDF: 12 pages
J. Biomed. Opt. 16(11) 116020 doi: 10.1117/1.3653235
Published in: Journal of Biomedical Optics Volume 16, Issue 11
Show Author Affiliations
Peter Cimalla, Universitätsklinikum Carl Gustav Carus Dresden (Germany)
Julia Walther, Universitätsklinikum Carl Gustav Carus Dresden (Germany)
Matthaeus Mittasch, Universitätsklinikum Carl Gustav Carus Dresden (Germany)
Edmund Koch, Universitätsklinikum Carl Gustav Carus Dresden (Germany)

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