Hematocrit-dependence of the scattering coefficient of blood determined by optical coherence tomography

Faber, Dirk J.; Meer, Freek J. van der; Aalders, Maurice C. G.; Bruin, Daniël M. de; Leeuwen, Ton G. van

doi:10.1117/12.632990

Cited by 6 publications

(6 citation statements)

References 13 publications

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“…This was obtained from the Mie scattering cross section s using the approximation equation 29 s = Hct͑1 − Hct͒͑ s / V͒, where V is the volume of the scatterer. However, depending on wavelength, the measured values are on average 59% lower, indicating that the prerequisite of independent scattering without interference phenomena is gradually eliminated by the decrease in the mean distances between the cells as discussed by Faber et al 20 The data of Yaroslavsky et al 7 Reynolds, 18 and Roggan et al 2 confirms the measurements presented here in contrast to the Mie theoretical values. An exception to this is Hammer et al 21 who presented data at 514 nm, even higher than the value given by the Mie theory.…”

Section: Optical Parameters Of Blood In Physiological Concentrationsupporting

confidence: 84%

“…There the reflection is increased, induced by the increase in the complex refractive index, and the transmission is decreased by increased absorption within the cell. Moreover, some investigations indicate that in the case of high hematocrit levels, the scattering anisotropy of red blood cells is strongly influenced by the flow conditions [12][13][14] particularly the shear-rate-dependent aggregation and disaggregation phenomena 4,[15][16][17] Although there are a number of further studies about the optical parameters of blood, 2,3,[18][19][20] there is only limited information available about the effective phase function of undiluted blood, 21 and only for single wavelengths.…”

Section: Introductionmentioning

confidence: 99%

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Determination of optical properties of human blood in the spectral range 250 to 1100 nm using Monte Carlo simulations with hematocrit-dependent effective scattering phase functions

et al. 2006

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The absorption coefficient mu(a), scattering coefficient mu(s), and anisotropy factor g of diluted and undiluted human blood (hematocrit 0.84 and 42.1%) are determined under flow conditions in the wavelength range 250 to 1100 nm, covering the absorption bands of hemoglobin. These values are obtained by high precision integrating sphere measurements in combination with an optimized inverse Monte Carlo simulation (IMCS). With a new algorithm, appropriate effective phase functions could be evaluated for both blood concentrations using the IMCS. The best results are obtained using the Reynolds-McCormick phase function with the variation factor alpha = 1.2 for hematocrit 0.84%, and alpha = 1.7 for hematocrit 42.1%. The obtained data are compared with the parameters given by the Mie theory. The use of IMCS in combination with selected appropriate effective phase functions make it possible to take into account the nonspherical shape of erythrocytes, the phenomenon of coupled absorption and scattering, and multiple scattering and interference phenomena. It is therefore possible for the first time to obtain reasonable results for the optical behavior of human blood, even at high hematocrit and in high hemoglobin absorption areas. Moreover, the limitations of the Mie theory describing the optical properties of blood can be shown.

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Section: Optical Parameters Of Blood In Physiological Concentrationsupporting

confidence: 84%

Section: Introductionmentioning

confidence: 99%

Determination of optical properties of human blood in the spectral range 250 to 1100 nm using Monte Carlo simulations with hematocrit-dependent effective scattering phase functions

et al. 2006

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“…The sO 2 changes were monitored using two optical wavelengths: 650 nm ( ε Hb /ε Hbo 2 = 10.1) and 750 nm ( ε Hb /ε Hbo 2 = 2.7). The optical parameters for the blood and tissue were assigned according to references [12, 13]. Figure 1(b) shows the sO 2 values calculated using the dynamic and conventional methods.…”

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confidence: 99%

Calibration-free quantification of absolute oxygen saturation based on the dynamics of photoacoustic signals

et al. 2013

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Photoacoustic tomography (PAT) is a hybrid imaging technique that has broad preclinical and clinical applications. Based on the photoacoustic effect, PAT directly measures specific optical absorption, which is the product of the tissue-intrinsic optical absorption coefficient and the local optical fluence. Therefore, quantitative PAT, such as absolute oxygen saturation (sO2) quantification, requires knowledge of the local optical fluence, which can be estimated only through invasive measurements or sophisticated modeling of light transportation. In this work, we circumvent this requirement by taking advantage of the dynamics in sO2. The new method works when the sO2 transition can be simultaneously monitored with multiple wavelengths. For each wavelength, the ratio of photoacoustic amplitudes measured at different sO2 states is utilized. Using the ratio cancels the contribution from optical fluence and allows calibration-free quantification of absolute sO2. The new method was validated through both phantom and in vivo experiments.

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“…μ t_OxyB [cm -1 ] and μ t_DeOxyB [cm -1 ] are the compound attenuation coefficients of fully oxygenated and fully deoxygenated whole blood, respectively. The compound attenuation coefficient spectrum of μ t_OxyB and μ t_DeOxyB were obtained as the linear combination of the absorption coefficients, scattering coefficients, and the packing factor of whole blood [43]

\begin{matrix} μ_{t_italicOxyB} = μ_{a_italicOxyB} + W \cdot μ_{s_italicOxyB}, \\ μ_{t_italicDeOxyB} = μ_{a_italicDeOxyB} + W \cdot μ_{s_italicDeOxyB} . \end{matrix}

…”

Section: Methodsmentioning

confidence: 99%

Monte Carlo Investigation of Optical Coherence Tomography Retinal Oximetry

Chen¹,

Yi²,

Liu³

et al. 2015

IEEE Trans. Biomed. Eng.

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Optical coherence tomography (OCT) oximetry explores the possibility to measure retinal hemoglobin oxygen saturation level (sO2). We investigated the accuracy of OCT retinal oximetry using Monte Carlo simulation in a commonly-used four-layer retinal model. After we determined the appropriate number of simulated photon packets, we studied the effects of blood vessel diameter, signal sampling position, physiological sO2 level, and the blood packing factor on the accuracy of sO2 estimation in OCT retinal oximetry. The simulation results showed that a packing factor between 0.2 and 0.4 yields a reasonably accurate estimation of sO2 within a 5% error tolerance, which is independent of vessel diameter and sampling position, when visible-light illumination is used in OCT. We further explored the optimal optical spectral range for OCT retinal oximetry. The simulation results suggest that visible spectral range around 560 nm is better suited than near-infrared spectral range around 800 nm for OCT oximetry to warrant accurate measurements.

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Hematocrit-dependence of the scattering coefficient of blood determined by optical coherence tomography

Cited by 6 publications

References 13 publications

Determination of optical properties of human blood in the spectral range 250 to 1100 nm using Monte Carlo simulations with hematocrit-dependent effective scattering phase functions

Determination of optical properties of human blood in the spectral range 250 to 1100 nm using Monte Carlo simulations with hematocrit-dependent effective scattering phase functions

Calibration-free quantification of absolute oxygen saturation based on the dynamics of photoacoustic signals

Monte Carlo Investigation of Optical Coherence Tomography Retinal Oximetry

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