Advertisement

Absolute Values of Optical Properties (μa, μ΄s, μeff and DPF) of Human Head Tissue: Dependence on Head Region and Individual

  • Felix Scholkmann
  • Hamoon Zohdi
  • Nassim Nasseri
  • Ursula Wolf
Chapter
Part of the Advances in Experimental Medicine and Biology book series (AEMB, volume 1072)

Abstract

Background: Absolute optical properties (i.e., the absorption coefficient, μa, and the reduced scattering coefficient, \( {\mu}_{\mathrm{s}}^{\prime } \)) of head tissue can be measured with frequency-domain near-infrared spectroscopy (FD-NIRS). Aim: We investigated how the absolute optical properties depend on the individual subject and the head region. Materials and Methods: The data set used for the analysis comprised 31 single FD-NIRS measurements of 14 healthy subjects (9 men, 5 women, aged 33.4 ± 10.5 years). From an 8-min measurement (resting-state; FD-NIRS device: Imagent, ISS Inc.; bilateral over the prefrontal cortex, PFC, and visual cortex, VC) median values were calculated for μa and \( {\mu}_{\mathrm{s}}^{\prime } \) as well as the effective attenuation coefficient (μeff) and the differential pathlength factor (DPF). The measurement was done for each subject one to three times with at least 24 h between the measurements. Results: (i) A Bayesian ANOVA analysis revealed that head region and subject were the most significant main effects on μa, \( {\mu}_{\mathrm{s}}^{\prime } \) and μeff, as well as DPF, respectively. (ii) At the VC, μa, \( {\mu}_{\mathrm{s}}^{\prime } \) and μeff had higher values compared to the PFC. (iii) The differences in the optical properties between PFC and VC were age-dependent. (iv) All optical properties also were age-dependent. This was strongest for the properties of the PFC compared to the VC. Discussion and Conclusion: Our analysis demonstrates that all optical head tissue properties (μa, \( {\mu}_{\mathrm{s}}^{\prime } \), μeff and DPF) were dependent on the head region, individual subject and age. The optical properties of the head are like a ‘fingerprint’ for the individual subject. Assuming constant optical properties for the whole head should be carefully reconsidered.

References

  1. 1.
    Toronov V, Webb A, Choi JH et al (2001) Study of local cerebral hemodynamics by frequency-domain near-infrared spectroscopy and correlation with simultaneously acquired functional magnetic resonance imaging. Opt Express 9(8):417–427CrossRefPubMedGoogle Scholar
  2. 2.
    Zohdi H, Scholkmann F, Nasseri N et al (2018) Long-term changes in optical properties (μa, μs´, μeff and DPF) of human head tissue during functional neuroimaging experiments. In: Advances in Experimental Medicine and Biology. Springer, ChamGoogle Scholar
  3. 3.
    Chiarelli AM, Maclin EL, Low KA, Fantini S et al (2017) Low-resolution mapping of the effective attenuation coefficient of the human head: a multidistance approach applied to high-density optical recordings. Neurophotonics 4(2):021103CrossRefPubMedPubMedCentralGoogle Scholar
  4. 4.
    Zhao H, Tanikawa Y, Gao F, Onodera Y et al (2002) Maps of optical differential pathlength factor of human adult forehead, somatosensory motor and occipital regions at multi-wavelengths in NIR. Phys Med Biol 47(12):2075–2093CrossRefPubMedGoogle Scholar
  5. 5.
    Scholkmann F, Wolf M (2013) General equation for the differential pathlength factor of the frontal human head depending on wavelength and age. J Biomed Opt 18(10):105004CrossRefPubMedGoogle Scholar
  6. 6.
    Katagiri A, Dan I, Tuzuki D et al (2010) Mapping of optical pathlength of human adult head at multi-wavelengths in near infrared spectroscopy. Adv Exp Med Biol 662:205–212CrossRefPubMedGoogle Scholar
  7. 7.
    Strangman GE, Zhang Q, Li Z (2014) Scalp and skull influence on near infrared photon propagation in the Colin27 brain template. NeuroImage 85(1):136–149CrossRefPubMedGoogle Scholar
  8. 8.
    Highton D, Tachtsidis I, Tucker A et al (2016) Near infrared light scattering changes following acute brain injury. Adv Exp Med Biol 876:139–144CrossRefPubMedGoogle Scholar

Copyright information

© Springer International Publishing AG, part of Springer Nature 2018

Authors and Affiliations

  • Felix Scholkmann
    • 1
    • 2
  • Hamoon Zohdi
    • 1
  • Nassim Nasseri
    • 1
  • Ursula Wolf
    • 1
  1. 1.University of Bern, Institute of Complementary MedicineBernSwitzerland
  2. 2.University Hospital Zurich, University of Zurich, Department of Neonatology, Biomedical Optics Research LaboratoryZurichSwitzerland

Personalised recommendations