Abstract

Laser-Doppler flow measurements with penetration depths from 10 to 30 mm have been performed on a layered model of the human head consisting of a regular array of capillaries with diameters of 340 µm embedded in an epoxy matrix with tissuelike scattering and absorption properties. Monte Carlo simulations and an analytical approach based on diffusing wave spectroscopy have corroborated the measurements and have led to a quantitative description of flow in deep-lying tissue layers with regard to layers near the surface also. The results indicate that it may be possible to measure changes in cortical blood flow even in the presence of a well-perfused scalp.

© 1999 Optical Society of America

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References

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  1. P. van der Zee, M. Essenpreis, D. T. Delpy, “Optical properties of brain tissue,” in Photon Migration and Imaging in Random Media and Tissues, B. Chance, R. R. Alfano, A. Katzir, eds., Proc. SPIE1888, 454–465 (1993).
    [CrossRef]
  2. H. Obrig, A. Villringer, “Near-infrared spectroscopy in functional activation studies,” in Optical Imaging of Brain Function and Metabolism, A. Villringer, U. Dirnagl, eds. (Plenum, New York, 1997), Vol. II, pp. 113–127.
  3. A. Kleinschmidt, H. Obrig, M. Requardt, K.-D. Merboldt, U. Dirnagl, A. Villringer, J. Frahm, “Simultaneous recording of cerebral blood oxygenation changes during human brain activation by magnetic resonance imaging and near-infrared spectroscopy,” J. Cereb. Blood Flow Metab. 16, 817–826 (1996).
    [CrossRef] [PubMed]
  4. M. Cope, “The development of a near infrared spectroscopy system and its application for non invasive monitoring of cerebral blood and tissue oxygenation in the newborn infant,” Ph.D. dissertation (University College London, London, 1991).
  5. M. Fabiani, G. Gratton, P. M. Corballis, “Noninvasive near infrared optical imaging of human brain function with subsecond temporal resolution,” J. Biomed. Opt. 1, 387–398 (1996).
    [CrossRef] [PubMed]
  6. Y. Hoshi, M. Tamura, “Detection of dynamic changes in cerebral oxygenation coupled to neuronal function during mental work in man,” Neurosci. Lett. 150, 5–8 (1993).
    [CrossRef] [PubMed]
  7. Y. Yamashita, A. Maki, Y. Ito, E. Watanabe, Y. Mayanagi, H. Koizumi, “Noninvasive near-infrared topography of human brain activity using intensity modulation spectroscopy,” Opt. Eng. 35, 1046–1049 (1996).
    [CrossRef]
  8. G. Soelkner, G. Mitic, R. Lohwasser, “Monte Carlo simulations and laser Doppler flow measurements with high penetration depth in biological tissuelike head phantoms,” Appl. Opt. 36, 5647–5654 (1997).
    [CrossRef] [PubMed]
  9. R. Skalak, S. Chien, “Capillary flow: history, experiments and theory,” Biorheology 18, 307–330 (1981).
    [PubMed]
  10. M. Firbank, M. Schweiger, D. T. Delpy, “Investigation of ‘light piping’ through clear regions of scattering objects,” in Optical Tomography, Photon Migration, and Spectroscopy of Tissue and Model Media: Theory, Human Studies, and Instrumentation, B. Chance, R. R. Alfano, A. Katzir, eds., Proc. SPIE2389, 167–173 (1995).
    [CrossRef]
  11. M. S. Patterson, B. Chance, B. C. Wilson, “Time resolved reflectance and transmittance for the noninvasive measurement of tissue optical properties,” Appl. Opt. 28, 2331–2336 (1989).
    [CrossRef] [PubMed]
  12. E. M. Sevick, “Photon migration in a model of the head measured using time- and frequency-domain techniques: potentials of spectroscopy and imaging,” in Time-Resolved Spectroscopy and Imaging of Tissues, B. Chance, A. Katzir, eds., Proc. SPIE1431, 84–96 (1991).
    [CrossRef]
  13. I. A. Hein, W. D. O’Brien, “A flexible blood flow phantom capable of independently producing constant and pulsatile flow with a predictable spatial flow profile for ultrasound flow measurement validations,” IEEE Trans. Biomed. Eng. 39, 1111–1122 (1992).
    [CrossRef] [PubMed]
  14. H. Z. Cummings, H. L. Swinney, “The theory of light beating spectroscopy,” in Progress in Optics, E. Wolf, ed. (North-Holland, Amsterdam, 1970), Vol. VIII, pp. 141–154.
  15. D. J. Pine, D. A. Weitz, J. X. Zhu, E. Herbolzheimer, “Diffusing-wave spectroscopy: dynamic light scattering in the multiple scattering limit,” J. Phys. (France) 51, 2101–2127 (1990).
  16. G. Maret, P. E. Wolf, “Multiple light scattering from disordered media. The effect of Brownian motion of scatters,” Z. Phys. B 65, 409–413 (1987).
    [CrossRef]
  17. F. F. M. de Mul, M. H. Koelink, M. L. Kok, P. J. Harmsma, J. Greve, R. Graaff, J. G. Aarnoudse, “Laser Doppler velocimetry and Monte Carlo simulations on models for blood perfusion in tissue,” Appl. Opt. 34, 6595–6611 (1995).
    [CrossRef] [PubMed]
  18. G. Gratton, M. Fabiani, D. Friedman, M. A. Franceschini, S. Fantini, P. Corballis, E. Gratton, “Rapid changes of optical parameters in the human brain during a tapping task,” J. Cogn. Neurosci. 7, 446–456 (1995).
    [CrossRef] [PubMed]
  19. R. Bonner, R. Nossal, “Model for laser Doppler measurements of blood flow in tissue,” Appl. Opt. 20, 2097–2107 (1981).
    [CrossRef] [PubMed]

1997

1996

Y. Yamashita, A. Maki, Y. Ito, E. Watanabe, Y. Mayanagi, H. Koizumi, “Noninvasive near-infrared topography of human brain activity using intensity modulation spectroscopy,” Opt. Eng. 35, 1046–1049 (1996).
[CrossRef]

A. Kleinschmidt, H. Obrig, M. Requardt, K.-D. Merboldt, U. Dirnagl, A. Villringer, J. Frahm, “Simultaneous recording of cerebral blood oxygenation changes during human brain activation by magnetic resonance imaging and near-infrared spectroscopy,” J. Cereb. Blood Flow Metab. 16, 817–826 (1996).
[CrossRef] [PubMed]

M. Fabiani, G. Gratton, P. M. Corballis, “Noninvasive near infrared optical imaging of human brain function with subsecond temporal resolution,” J. Biomed. Opt. 1, 387–398 (1996).
[CrossRef] [PubMed]

1995

G. Gratton, M. Fabiani, D. Friedman, M. A. Franceschini, S. Fantini, P. Corballis, E. Gratton, “Rapid changes of optical parameters in the human brain during a tapping task,” J. Cogn. Neurosci. 7, 446–456 (1995).
[CrossRef] [PubMed]

F. F. M. de Mul, M. H. Koelink, M. L. Kok, P. J. Harmsma, J. Greve, R. Graaff, J. G. Aarnoudse, “Laser Doppler velocimetry and Monte Carlo simulations on models for blood perfusion in tissue,” Appl. Opt. 34, 6595–6611 (1995).
[CrossRef] [PubMed]

1993

Y. Hoshi, M. Tamura, “Detection of dynamic changes in cerebral oxygenation coupled to neuronal function during mental work in man,” Neurosci. Lett. 150, 5–8 (1993).
[CrossRef] [PubMed]

1992

I. A. Hein, W. D. O’Brien, “A flexible blood flow phantom capable of independently producing constant and pulsatile flow with a predictable spatial flow profile for ultrasound flow measurement validations,” IEEE Trans. Biomed. Eng. 39, 1111–1122 (1992).
[CrossRef] [PubMed]

1990

D. J. Pine, D. A. Weitz, J. X. Zhu, E. Herbolzheimer, “Diffusing-wave spectroscopy: dynamic light scattering in the multiple scattering limit,” J. Phys. (France) 51, 2101–2127 (1990).

1989

1987

G. Maret, P. E. Wolf, “Multiple light scattering from disordered media. The effect of Brownian motion of scatters,” Z. Phys. B 65, 409–413 (1987).
[CrossRef]

1981

R. Skalak, S. Chien, “Capillary flow: history, experiments and theory,” Biorheology 18, 307–330 (1981).
[PubMed]

R. Bonner, R. Nossal, “Model for laser Doppler measurements of blood flow in tissue,” Appl. Opt. 20, 2097–2107 (1981).
[CrossRef] [PubMed]

Aarnoudse, J. G.

Bonner, R.

Chance, B.

Chien, S.

R. Skalak, S. Chien, “Capillary flow: history, experiments and theory,” Biorheology 18, 307–330 (1981).
[PubMed]

Cope, M.

M. Cope, “The development of a near infrared spectroscopy system and its application for non invasive monitoring of cerebral blood and tissue oxygenation in the newborn infant,” Ph.D. dissertation (University College London, London, 1991).

Corballis, P.

G. Gratton, M. Fabiani, D. Friedman, M. A. Franceschini, S. Fantini, P. Corballis, E. Gratton, “Rapid changes of optical parameters in the human brain during a tapping task,” J. Cogn. Neurosci. 7, 446–456 (1995).
[CrossRef] [PubMed]

Corballis, P. M.

M. Fabiani, G. Gratton, P. M. Corballis, “Noninvasive near infrared optical imaging of human brain function with subsecond temporal resolution,” J. Biomed. Opt. 1, 387–398 (1996).
[CrossRef] [PubMed]

Cummings, H. Z.

H. Z. Cummings, H. L. Swinney, “The theory of light beating spectroscopy,” in Progress in Optics, E. Wolf, ed. (North-Holland, Amsterdam, 1970), Vol. VIII, pp. 141–154.

de Mul, F. F. M.

Delpy, D. T.

M. Firbank, M. Schweiger, D. T. Delpy, “Investigation of ‘light piping’ through clear regions of scattering objects,” in Optical Tomography, Photon Migration, and Spectroscopy of Tissue and Model Media: Theory, Human Studies, and Instrumentation, B. Chance, R. R. Alfano, A. Katzir, eds., Proc. SPIE2389, 167–173 (1995).
[CrossRef]

P. van der Zee, M. Essenpreis, D. T. Delpy, “Optical properties of brain tissue,” in Photon Migration and Imaging in Random Media and Tissues, B. Chance, R. R. Alfano, A. Katzir, eds., Proc. SPIE1888, 454–465 (1993).
[CrossRef]

Dirnagl, U.

A. Kleinschmidt, H. Obrig, M. Requardt, K.-D. Merboldt, U. Dirnagl, A. Villringer, J. Frahm, “Simultaneous recording of cerebral blood oxygenation changes during human brain activation by magnetic resonance imaging and near-infrared spectroscopy,” J. Cereb. Blood Flow Metab. 16, 817–826 (1996).
[CrossRef] [PubMed]

Essenpreis, M.

P. van der Zee, M. Essenpreis, D. T. Delpy, “Optical properties of brain tissue,” in Photon Migration and Imaging in Random Media and Tissues, B. Chance, R. R. Alfano, A. Katzir, eds., Proc. SPIE1888, 454–465 (1993).
[CrossRef]

Fabiani, M.

M. Fabiani, G. Gratton, P. M. Corballis, “Noninvasive near infrared optical imaging of human brain function with subsecond temporal resolution,” J. Biomed. Opt. 1, 387–398 (1996).
[CrossRef] [PubMed]

G. Gratton, M. Fabiani, D. Friedman, M. A. Franceschini, S. Fantini, P. Corballis, E. Gratton, “Rapid changes of optical parameters in the human brain during a tapping task,” J. Cogn. Neurosci. 7, 446–456 (1995).
[CrossRef] [PubMed]

Fantini, S.

G. Gratton, M. Fabiani, D. Friedman, M. A. Franceschini, S. Fantini, P. Corballis, E. Gratton, “Rapid changes of optical parameters in the human brain during a tapping task,” J. Cogn. Neurosci. 7, 446–456 (1995).
[CrossRef] [PubMed]

Firbank, M.

M. Firbank, M. Schweiger, D. T. Delpy, “Investigation of ‘light piping’ through clear regions of scattering objects,” in Optical Tomography, Photon Migration, and Spectroscopy of Tissue and Model Media: Theory, Human Studies, and Instrumentation, B. Chance, R. R. Alfano, A. Katzir, eds., Proc. SPIE2389, 167–173 (1995).
[CrossRef]

Frahm, J.

A. Kleinschmidt, H. Obrig, M. Requardt, K.-D. Merboldt, U. Dirnagl, A. Villringer, J. Frahm, “Simultaneous recording of cerebral blood oxygenation changes during human brain activation by magnetic resonance imaging and near-infrared spectroscopy,” J. Cereb. Blood Flow Metab. 16, 817–826 (1996).
[CrossRef] [PubMed]

Franceschini, M. A.

G. Gratton, M. Fabiani, D. Friedman, M. A. Franceschini, S. Fantini, P. Corballis, E. Gratton, “Rapid changes of optical parameters in the human brain during a tapping task,” J. Cogn. Neurosci. 7, 446–456 (1995).
[CrossRef] [PubMed]

Friedman, D.

G. Gratton, M. Fabiani, D. Friedman, M. A. Franceschini, S. Fantini, P. Corballis, E. Gratton, “Rapid changes of optical parameters in the human brain during a tapping task,” J. Cogn. Neurosci. 7, 446–456 (1995).
[CrossRef] [PubMed]

Graaff, R.

Gratton, E.

G. Gratton, M. Fabiani, D. Friedman, M. A. Franceschini, S. Fantini, P. Corballis, E. Gratton, “Rapid changes of optical parameters in the human brain during a tapping task,” J. Cogn. Neurosci. 7, 446–456 (1995).
[CrossRef] [PubMed]

Gratton, G.

M. Fabiani, G. Gratton, P. M. Corballis, “Noninvasive near infrared optical imaging of human brain function with subsecond temporal resolution,” J. Biomed. Opt. 1, 387–398 (1996).
[CrossRef] [PubMed]

G. Gratton, M. Fabiani, D. Friedman, M. A. Franceschini, S. Fantini, P. Corballis, E. Gratton, “Rapid changes of optical parameters in the human brain during a tapping task,” J. Cogn. Neurosci. 7, 446–456 (1995).
[CrossRef] [PubMed]

Greve, J.

Harmsma, P. J.

Hein, I. A.

I. A. Hein, W. D. O’Brien, “A flexible blood flow phantom capable of independently producing constant and pulsatile flow with a predictable spatial flow profile for ultrasound flow measurement validations,” IEEE Trans. Biomed. Eng. 39, 1111–1122 (1992).
[CrossRef] [PubMed]

Herbolzheimer, E.

D. J. Pine, D. A. Weitz, J. X. Zhu, E. Herbolzheimer, “Diffusing-wave spectroscopy: dynamic light scattering in the multiple scattering limit,” J. Phys. (France) 51, 2101–2127 (1990).

Hoshi, Y.

Y. Hoshi, M. Tamura, “Detection of dynamic changes in cerebral oxygenation coupled to neuronal function during mental work in man,” Neurosci. Lett. 150, 5–8 (1993).
[CrossRef] [PubMed]

Ito, Y.

Y. Yamashita, A. Maki, Y. Ito, E. Watanabe, Y. Mayanagi, H. Koizumi, “Noninvasive near-infrared topography of human brain activity using intensity modulation spectroscopy,” Opt. Eng. 35, 1046–1049 (1996).
[CrossRef]

Kleinschmidt, A.

A. Kleinschmidt, H. Obrig, M. Requardt, K.-D. Merboldt, U. Dirnagl, A. Villringer, J. Frahm, “Simultaneous recording of cerebral blood oxygenation changes during human brain activation by magnetic resonance imaging and near-infrared spectroscopy,” J. Cereb. Blood Flow Metab. 16, 817–826 (1996).
[CrossRef] [PubMed]

Koelink, M. H.

Koizumi, H.

Y. Yamashita, A. Maki, Y. Ito, E. Watanabe, Y. Mayanagi, H. Koizumi, “Noninvasive near-infrared topography of human brain activity using intensity modulation spectroscopy,” Opt. Eng. 35, 1046–1049 (1996).
[CrossRef]

Kok, M. L.

Lohwasser, R.

Maki, A.

Y. Yamashita, A. Maki, Y. Ito, E. Watanabe, Y. Mayanagi, H. Koizumi, “Noninvasive near-infrared topography of human brain activity using intensity modulation spectroscopy,” Opt. Eng. 35, 1046–1049 (1996).
[CrossRef]

Maret, G.

G. Maret, P. E. Wolf, “Multiple light scattering from disordered media. The effect of Brownian motion of scatters,” Z. Phys. B 65, 409–413 (1987).
[CrossRef]

Mayanagi, Y.

Y. Yamashita, A. Maki, Y. Ito, E. Watanabe, Y. Mayanagi, H. Koizumi, “Noninvasive near-infrared topography of human brain activity using intensity modulation spectroscopy,” Opt. Eng. 35, 1046–1049 (1996).
[CrossRef]

Merboldt, K.-D.

A. Kleinschmidt, H. Obrig, M. Requardt, K.-D. Merboldt, U. Dirnagl, A. Villringer, J. Frahm, “Simultaneous recording of cerebral blood oxygenation changes during human brain activation by magnetic resonance imaging and near-infrared spectroscopy,” J. Cereb. Blood Flow Metab. 16, 817–826 (1996).
[CrossRef] [PubMed]

Mitic, G.

Nossal, R.

O’Brien, W. D.

I. A. Hein, W. D. O’Brien, “A flexible blood flow phantom capable of independently producing constant and pulsatile flow with a predictable spatial flow profile for ultrasound flow measurement validations,” IEEE Trans. Biomed. Eng. 39, 1111–1122 (1992).
[CrossRef] [PubMed]

Obrig, H.

A. Kleinschmidt, H. Obrig, M. Requardt, K.-D. Merboldt, U. Dirnagl, A. Villringer, J. Frahm, “Simultaneous recording of cerebral blood oxygenation changes during human brain activation by magnetic resonance imaging and near-infrared spectroscopy,” J. Cereb. Blood Flow Metab. 16, 817–826 (1996).
[CrossRef] [PubMed]

H. Obrig, A. Villringer, “Near-infrared spectroscopy in functional activation studies,” in Optical Imaging of Brain Function and Metabolism, A. Villringer, U. Dirnagl, eds. (Plenum, New York, 1997), Vol. II, pp. 113–127.

Patterson, M. S.

Pine, D. J.

D. J. Pine, D. A. Weitz, J. X. Zhu, E. Herbolzheimer, “Diffusing-wave spectroscopy: dynamic light scattering in the multiple scattering limit,” J. Phys. (France) 51, 2101–2127 (1990).

Requardt, M.

A. Kleinschmidt, H. Obrig, M. Requardt, K.-D. Merboldt, U. Dirnagl, A. Villringer, J. Frahm, “Simultaneous recording of cerebral blood oxygenation changes during human brain activation by magnetic resonance imaging and near-infrared spectroscopy,” J. Cereb. Blood Flow Metab. 16, 817–826 (1996).
[CrossRef] [PubMed]

Schweiger, M.

M. Firbank, M. Schweiger, D. T. Delpy, “Investigation of ‘light piping’ through clear regions of scattering objects,” in Optical Tomography, Photon Migration, and Spectroscopy of Tissue and Model Media: Theory, Human Studies, and Instrumentation, B. Chance, R. R. Alfano, A. Katzir, eds., Proc. SPIE2389, 167–173 (1995).
[CrossRef]

Sevick, E. M.

E. M. Sevick, “Photon migration in a model of the head measured using time- and frequency-domain techniques: potentials of spectroscopy and imaging,” in Time-Resolved Spectroscopy and Imaging of Tissues, B. Chance, A. Katzir, eds., Proc. SPIE1431, 84–96 (1991).
[CrossRef]

Skalak, R.

R. Skalak, S. Chien, “Capillary flow: history, experiments and theory,” Biorheology 18, 307–330 (1981).
[PubMed]

Soelkner, G.

Swinney, H. L.

H. Z. Cummings, H. L. Swinney, “The theory of light beating spectroscopy,” in Progress in Optics, E. Wolf, ed. (North-Holland, Amsterdam, 1970), Vol. VIII, pp. 141–154.

Tamura, M.

Y. Hoshi, M. Tamura, “Detection of dynamic changes in cerebral oxygenation coupled to neuronal function during mental work in man,” Neurosci. Lett. 150, 5–8 (1993).
[CrossRef] [PubMed]

van der Zee, P.

P. van der Zee, M. Essenpreis, D. T. Delpy, “Optical properties of brain tissue,” in Photon Migration and Imaging in Random Media and Tissues, B. Chance, R. R. Alfano, A. Katzir, eds., Proc. SPIE1888, 454–465 (1993).
[CrossRef]

Villringer, A.

A. Kleinschmidt, H. Obrig, M. Requardt, K.-D. Merboldt, U. Dirnagl, A. Villringer, J. Frahm, “Simultaneous recording of cerebral blood oxygenation changes during human brain activation by magnetic resonance imaging and near-infrared spectroscopy,” J. Cereb. Blood Flow Metab. 16, 817–826 (1996).
[CrossRef] [PubMed]

H. Obrig, A. Villringer, “Near-infrared spectroscopy in functional activation studies,” in Optical Imaging of Brain Function and Metabolism, A. Villringer, U. Dirnagl, eds. (Plenum, New York, 1997), Vol. II, pp. 113–127.

Watanabe, E.

Y. Yamashita, A. Maki, Y. Ito, E. Watanabe, Y. Mayanagi, H. Koizumi, “Noninvasive near-infrared topography of human brain activity using intensity modulation spectroscopy,” Opt. Eng. 35, 1046–1049 (1996).
[CrossRef]

Weitz, D. A.

D. J. Pine, D. A. Weitz, J. X. Zhu, E. Herbolzheimer, “Diffusing-wave spectroscopy: dynamic light scattering in the multiple scattering limit,” J. Phys. (France) 51, 2101–2127 (1990).

Wilson, B. C.

Wolf, P. E.

G. Maret, P. E. Wolf, “Multiple light scattering from disordered media. The effect of Brownian motion of scatters,” Z. Phys. B 65, 409–413 (1987).
[CrossRef]

Yamashita, Y.

Y. Yamashita, A. Maki, Y. Ito, E. Watanabe, Y. Mayanagi, H. Koizumi, “Noninvasive near-infrared topography of human brain activity using intensity modulation spectroscopy,” Opt. Eng. 35, 1046–1049 (1996).
[CrossRef]

Zhu, J. X.

D. J. Pine, D. A. Weitz, J. X. Zhu, E. Herbolzheimer, “Diffusing-wave spectroscopy: dynamic light scattering in the multiple scattering limit,” J. Phys. (France) 51, 2101–2127 (1990).

Appl. Opt.

Biorheology

R. Skalak, S. Chien, “Capillary flow: history, experiments and theory,” Biorheology 18, 307–330 (1981).
[PubMed]

IEEE Trans. Biomed. Eng.

I. A. Hein, W. D. O’Brien, “A flexible blood flow phantom capable of independently producing constant and pulsatile flow with a predictable spatial flow profile for ultrasound flow measurement validations,” IEEE Trans. Biomed. Eng. 39, 1111–1122 (1992).
[CrossRef] [PubMed]

J. Biomed. Opt.

M. Fabiani, G. Gratton, P. M. Corballis, “Noninvasive near infrared optical imaging of human brain function with subsecond temporal resolution,” J. Biomed. Opt. 1, 387–398 (1996).
[CrossRef] [PubMed]

J. Cereb. Blood Flow Metab.

A. Kleinschmidt, H. Obrig, M. Requardt, K.-D. Merboldt, U. Dirnagl, A. Villringer, J. Frahm, “Simultaneous recording of cerebral blood oxygenation changes during human brain activation by magnetic resonance imaging and near-infrared spectroscopy,” J. Cereb. Blood Flow Metab. 16, 817–826 (1996).
[CrossRef] [PubMed]

J. Cogn. Neurosci.

G. Gratton, M. Fabiani, D. Friedman, M. A. Franceschini, S. Fantini, P. Corballis, E. Gratton, “Rapid changes of optical parameters in the human brain during a tapping task,” J. Cogn. Neurosci. 7, 446–456 (1995).
[CrossRef] [PubMed]

J. Phys. (France)

D. J. Pine, D. A. Weitz, J. X. Zhu, E. Herbolzheimer, “Diffusing-wave spectroscopy: dynamic light scattering in the multiple scattering limit,” J. Phys. (France) 51, 2101–2127 (1990).

Neurosci. Lett.

Y. Hoshi, M. Tamura, “Detection of dynamic changes in cerebral oxygenation coupled to neuronal function during mental work in man,” Neurosci. Lett. 150, 5–8 (1993).
[CrossRef] [PubMed]

Opt. Eng.

Y. Yamashita, A. Maki, Y. Ito, E. Watanabe, Y. Mayanagi, H. Koizumi, “Noninvasive near-infrared topography of human brain activity using intensity modulation spectroscopy,” Opt. Eng. 35, 1046–1049 (1996).
[CrossRef]

Z. Phys. B

G. Maret, P. E. Wolf, “Multiple light scattering from disordered media. The effect of Brownian motion of scatters,” Z. Phys. B 65, 409–413 (1987).
[CrossRef]

Other

H. Z. Cummings, H. L. Swinney, “The theory of light beating spectroscopy,” in Progress in Optics, E. Wolf, ed. (North-Holland, Amsterdam, 1970), Vol. VIII, pp. 141–154.

E. M. Sevick, “Photon migration in a model of the head measured using time- and frequency-domain techniques: potentials of spectroscopy and imaging,” in Time-Resolved Spectroscopy and Imaging of Tissues, B. Chance, A. Katzir, eds., Proc. SPIE1431, 84–96 (1991).
[CrossRef]

M. Cope, “The development of a near infrared spectroscopy system and its application for non invasive monitoring of cerebral blood and tissue oxygenation in the newborn infant,” Ph.D. dissertation (University College London, London, 1991).

P. van der Zee, M. Essenpreis, D. T. Delpy, “Optical properties of brain tissue,” in Photon Migration and Imaging in Random Media and Tissues, B. Chance, R. R. Alfano, A. Katzir, eds., Proc. SPIE1888, 454–465 (1993).
[CrossRef]

H. Obrig, A. Villringer, “Near-infrared spectroscopy in functional activation studies,” in Optical Imaging of Brain Function and Metabolism, A. Villringer, U. Dirnagl, eds. (Plenum, New York, 1997), Vol. II, pp. 113–127.

M. Firbank, M. Schweiger, D. T. Delpy, “Investigation of ‘light piping’ through clear regions of scattering objects,” in Optical Tomography, Photon Migration, and Spectroscopy of Tissue and Model Media: Theory, Human Studies, and Instrumentation, B. Chance, R. R. Alfano, A. Katzir, eds., Proc. SPIE2389, 167–173 (1995).
[CrossRef]

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Figures (8)

Fig. 1
Fig. 1

Flow model of the head. Individual slabs of the phantom correspond to different tissue and bone layers of the head. The capillaries in the epoxy, which represent capillary blood vessels in the skin and the cortex, can be perfused with a scattering liquid. Light is guided from the laser and to the detector by optical fibers in close proximity to the top surface of the phantom. The fiber separation can be varied.

Fig. 2
Fig. 2

Preparing the cast of a slab with capillaries: a nylon string with a diameter of 340 µm is wound around a steel frame.

Fig. 3
Fig. 3

Steel frames with nylon strings after stacking in a mold and casting with epoxy. The steel frames have been cut so the nylon strings can be pulled out, thus forming capillaries in the epoxy. Later, the slab will be cut as shown by the dotted lines so the finished slab can be removed from the remaining stack of steel frames.

Fig. 4
Fig. 4

Schematic of the liquid circuit for perfusing the phantom. Diluted milk is pumped with compressed air from the lower storage container to the upper storage container from where it flows into the supply container. A height difference Δh i (i = I, II) forces the liquid through the respective slab to the recirculation container. SPCM, single-photon counting module.

Fig. 5
Fig. 5

Power spectrum of Brownian motion in the phantom, measured with the diluted milk at rest and compared with the result of DWS theory (fiber separation, 30 mm). Measured Doppler spectra at velocities 0.7 and 1.9 mm/s in slab II are also shown. The contribution of flow to the Doppler spectum is dominant at low frequencies up to at least 20 kHz.

Fig. 6
Fig. 6

Doppler power spectra at a liquid velocity of 1.0 mm/s. Measurement, Monte Carlo simulation, and analytical calculation are compared for slab I, slab II, and both slab I and slab II perfused simultaneously.

Fig. 7
Fig. 7

Doppler power spectra at a measured liquid velocity of 1.0 mm/s. Because of the low intensity of the detected light, noise is apparent in the spectra of slab I (A) and of slab II (B) at Doppler frequencies above 10 and 20 kHz, respectively.

Fig. 8
Fig. 8

Average flow velocity in slab II (cortex) as calculated from the measured Doppler spectrum versus flow velocity set for slab I (scalp). During the measurement the flow velocity set for slab II was kept constant at 1.0 mm/s. For fluid velocities in slab I not exceeding 1.6 mm/s, the error in the determination of the average flow velocity in slab II is less than 10%.

Equations (29)

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Δp=ρ×g×Δh,
vi=ΔViΔt×ni×di/22π,
g2τ=E*0E0E*τEτE*E2,
g1τ=E0E*τ|E02|,
g2τ=1+γ|g1τ|2,
En0En*τ=I0Pnexp-iqΔrτq,Δrn.
Δr2τ=6Dτ,
g1τ=0 Psexp-2τDk2sμsds,
Δrτ=14πvτ2 δΔrτ-vτ,
En0En*τ=I0Pn1qvτsinqvτqn,
q=2k0 1-cosϑ.
Pϑ=1-g24π1+g2-2g cosϑ3/2,
n=sμs.
Es0Es*τ=I0Ps12k2v2τ21-cos2kvτsμs.
g1iτj=s Pssi Psi|s×12k2vi2τj21-cos2kviτjsiαiμs.
Gifm=Δτ j=0J-1g1τjexp2πimjΔτΔf,
Sifn=m=0J-1 GifmGifn+m,
f=1/2πks-kiv,
f=- |f|Sfdf,
logSf=c+βf,
f1/β.
Qfmin, c, β; fmax, Sf=fmax-fmin-3×fminfmax |logSf-c-βf|df,
En0En*τ=I0PnΔr14πvτ2 δΔrτ-vτexp-iq·Δrτd3Δrqn.
En0En*τ=I0Pn×ϑ=0π12exp-iqvτ cos ψsinψdψqn,
En0En*τ=I0Pnξ=01cosqvτξdξqn,
En0En*τ=I0Pn1qvτsinqvτqn.
En0En*τ=I0Pn×02π0π1qϑvτsinqϑvτPg sin ϑdϑdφn. 
En0En*τ=I0Pn12k2vτ02k1k2vτsinqvτdqn.
En0En*τ=I0Pn12k2v2τ21-cos2kvτn.

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