Eiji Okada

Summary

Affiliation: Keio University
Country: Japan

Publications

  1. doi request reprint Theoretical and experimental investigation of the influence of frontal sinus on the sensitivity of the NIRS signal in the adult head
    Eiji Okada
    Department of Electronics and Electrical Engineering, Keio University, Yokohama, Japan
    Adv Exp Med Biol 662:231-6. 2010
  2. ncbi request reprint Near-infrared light propagation in an adult head model. I. Modeling of low-level scattering in the cerebrospinal fluid layer
    Eiji Okada
    Department of Electronics and Electrical Engineering, Keio University, 3 14 1 Hiyoshi, Kohoku Ku, Yokohama 223 8522, Japan
    Appl Opt 42:2906-14. 2003
  3. ncbi request reprint Near-infrared light propagation in an adult head model. II. Effect of superficial tissue thickness on the sensitivity of the near-infrared spectroscopy signal
    Eiji Okada
    Department of Electronics and Electrical Engineering, Keio University, 3 14 1 Hiyoshi, Kohoku Ku, Yokohama 223 8522, Japan
    Appl Opt 42:2915-22. 2003
  4. ncbi request reprint Practical and adequate approach to modeling light propagation in an adult head with low-scattering regions by use of diffusion theory
    Tatsuya Koyama
    Department of Electronics and Electrical Engineering, Keio University, 3 14 1 Hiyoshi, Kohoku Ku, Yokohama 223 8522, Japan
    Appl Opt 44:2094-103. 2005
  5. ncbi request reprint Experimental prediction of the wavelength-dependent path-length factor for optical intrinsic signal analysis
    Koichiro Sakaguchi
    Department of Electronics and Electrical Engineering, Keio University, Yokohama, Japan
    Appl Opt 46:2769-77. 2007
  6. ncbi request reprint Effect of probe arrangement on reproducibility of images by near-infrared topography evaluated by a virtual head phantom
    Hiroshi Kawaguchi
    Department of Electronics and Electrical Engineering, Keio University, Japan
    Appl Opt 46:1658-68. 2007
  7. ncbi request reprint Wavelength dependence of crosstalk in dual-wavelength measurement of oxy- and deoxy-hemoglobin
    Nobuhiro Okui
    Keio University, Department of Electronics and Electrical Engineering, 3 14 1, Hiyoshi, Kohoku Ku, Yokohama, 223 8522, Japan
    J Biomed Opt 10:11015. 2005
  8. ncbi request reprint Hybrid Monte Carlo-diffusion method for light propagation in tissue with a low-scattering region
    Toshiyuki Hayashi
    Department of Electronics and Electrical Engineering, Keio University 3 14 1, Hiyoshi Kohoku ku, Yokohama 223 8522, Japan
    Appl Opt 42:2888-96. 2003
  9. ncbi request reprint Interpretation of principal components of the reflectance spectra obtained from multispectral images of exposed pig brain
    Kentaro Yokoyama
    Keio University, Department of Electronics and Electrical Engineering, 3 14 1, Hiyoshi, Kohoku Ku, Yokohama, 223 8522, Japan
    J Biomed Opt 10:11005. 2005
  10. ncbi request reprint Monte Carlo prediction of near-infrared light propagation in realistic adult and neonatal head models
    Yuich Fukui
    Department of Electronics and Electrical Engineering, Keio University, 3 141, Hyoshi, Kohoku Ku, Yokohama 223 8522, Japan
    Appl Opt 42:2881-7. 2003

Collaborators

Detail Information

Publications14

  1. doi request reprint Theoretical and experimental investigation of the influence of frontal sinus on the sensitivity of the NIRS signal in the adult head
    Eiji Okada
    Department of Electronics and Electrical Engineering, Keio University, Yokohama, Japan
    Adv Exp Med Biol 662:231-6. 2010
    ..The influence of the frontal sinus on the sensitivity of the signal depends on the thickness of the skull and the depth of the frontal sinus...
  2. ncbi request reprint Near-infrared light propagation in an adult head model. I. Modeling of low-level scattering in the cerebrospinal fluid layer
    Eiji Okada
    Department of Electronics and Electrical Engineering, Keio University, 3 14 1 Hiyoshi, Kohoku Ku, Yokohama 223 8522, Japan
    Appl Opt 42:2906-14. 2003
    ..The sensitivity of the near-infrared signal to hemoglobin changes induced by brain activation is improved by the effect of a low-scattering CSF layer...
  3. ncbi request reprint Near-infrared light propagation in an adult head model. II. Effect of superficial tissue thickness on the sensitivity of the near-infrared spectroscopy signal
    Eiji Okada
    Department of Electronics and Electrical Engineering, Keio University, 3 14 1 Hiyoshi, Kohoku Ku, Yokohama 223 8522, Japan
    Appl Opt 42:2915-22. 2003
    ....
  4. ncbi request reprint Practical and adequate approach to modeling light propagation in an adult head with low-scattering regions by use of diffusion theory
    Tatsuya Koyama
    Department of Electronics and Electrical Engineering, Keio University, 3 14 1 Hiyoshi, Kohoku Ku, Yokohama 223 8522, Japan
    Appl Opt 44:2094-103. 2005
    ..3 mm(-1), it is practical to adopt diffusion theory to the modeling of light propagation in an adult head as an alternative to the hybrid method...
  5. ncbi request reprint Experimental prediction of the wavelength-dependent path-length factor for optical intrinsic signal analysis
    Koichiro Sakaguchi
    Department of Electronics and Electrical Engineering, Keio University, Yokohama, Japan
    Appl Opt 46:2769-77. 2007
    ..The experimentally predicted mean optical path length minimizes the difference in the measured changes in the concentrations of the oxygenated hemoglobin and deoxygenated hemoglobin calculated from different wavelength pairs...
  6. ncbi request reprint Effect of probe arrangement on reproducibility of images by near-infrared topography evaluated by a virtual head phantom
    Hiroshi Kawaguchi
    Department of Electronics and Electrical Engineering, Keio University, Japan
    Appl Opt 46:1658-68. 2007
    ..The overlapping measurements by the double-density probe arrangement can improve the reproducibility of the image obtained by NIR topography...
  7. ncbi request reprint Wavelength dependence of crosstalk in dual-wavelength measurement of oxy- and deoxy-hemoglobin
    Nobuhiro Okui
    Keio University, Department of Electronics and Electrical Engineering, 3 14 1, Hiyoshi, Kohoku Ku, Yokohama, 223 8522, Japan
    J Biomed Opt 10:11015. 2005
    ..The mean optical path length, which can be obtained by time- and phase-resolved measurement, is effective to reduce the crosstalk in the results of dual-wavelength measurement...
  8. ncbi request reprint Hybrid Monte Carlo-diffusion method for light propagation in tissue with a low-scattering region
    Toshiyuki Hayashi
    Department of Electronics and Electrical Engineering, Keio University 3 14 1, Hiyoshi Kohoku ku, Yokohama 223 8522, Japan
    Appl Opt 42:2888-96. 2003
    ..In the hybrid method, the time-consuming Monte Carlo calculation is employed only for the thin CSF layer, and hence, the computation time of the hybrid method is dramatically shorter than that of the Monte Carlo method...
  9. ncbi request reprint Interpretation of principal components of the reflectance spectra obtained from multispectral images of exposed pig brain
    Kentaro Yokoyama
    Keio University, Department of Electronics and Electrical Engineering, 3 14 1, Hiyoshi, Kohoku Ku, Yokohama, 223 8522, Japan
    J Biomed Opt 10:11005. 2005
    ..These results imply that the wavelength dependence of mean optical path length can be experimentally estimated from the first principal component of the reflectance spectra obtained from multispectral image of cortical tissue...
  10. ncbi request reprint Monte Carlo prediction of near-infrared light propagation in realistic adult and neonatal head models
    Yuich Fukui
    Department of Electronics and Electrical Engineering, Keio University, 3 141, Hyoshi, Kohoku Ku, Yokohama 223 8522, Japan
    Appl Opt 42:2881-7. 2003
    ..The intensely sensitive region in the neonatal brain is confined to the gray matter; however, the spatial sensitivity profile penetrates into the deeper region of the white matter...
  11. ncbi request reprint Influence of perfusion depth on laser Doppler flow measurements with large source-detector spacing
    Yohei Watanabe
    Department of Electronics, Keio University, 3 14 1, Hiyoshi, Kohoku Ku, Yokohama, 223, Japan
    Appl Opt 42:3198-204. 2003
    ..The influence of the depth of the perfusion on the Doppler spectrum depends on the path length that the detected light travels at different depths...
  12. pmc The influence of frontal sinus in brain activation measurements by near-infrared spectroscopy analyzed by realistic head models
    Kazuki Kurihara
    Department of Electronics and Electrical Engineering, Keio University, 3 14 1 Hiyoshi, Kohoku Ku, Yokohama, 223 8522, Japan
    Biomed Opt Express 3:2121-30. 2012
    ..The frontal sinus located in the shallow region of the skull tends to reduce the sensitivity of the NIRS signal while the deep frontal sinus can increase the sensitivity of the NIRS signal...
  13. ncbi request reprint Theoretical evaluation of accuracy in position and size of brain activity obtained by near-infrared topography
    Hiroshi Kawaguchi
    Department of Electronics and Electrical Engineering, Keio University, 3 14 1, Hiyoshi, Kohoku Ku, Yokohama, 223 8522, Japan
    Phys Med Biol 49:2753-65. 2004
    ..Near-infrared topography with the reconstruction method potentially obtains an accurate distribution of absorption change in the brain even if the size of absorption change is less than 10 mm...
  14. ncbi request reprint Arranging optical fibres for the spatial resolution improvement of topographical images
    Tsuyoshi Yamamoto
    Advanced Research Laboratory, Hitachi, Ltd, Saitama, Japan
    Phys Med Biol 47:3429-40. 2002
    ..The correlations between the activated area and the corresponding topographical images are obtained, and the effective arrangement of the optical fibres for improved resolution is discussed...