Dual Layered Models of Light Scattering in the Near Infrared A: Optical Measurements and Simulation

Almajidy, Rand K.; Rackebrandt, Klaas; Gehring, Hartmut; Hofmann, Ulrich G.

doi:10.1109/embc.2019.8857449

Cited by 1 publication

(1 citation statement)

References 28 publications

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“…A better approach would be to use multi-layered tissue diffusion models. 58 – 60 Another potential solution to address the partial volume effects is to use time-domain approaches 61 that use optical measurements from one source–detector pair to fully solve the photon diffusion equation. However, because they need specialized light sources and complex instrumentation, TD instruments are not commercially available and are less common in the clinic.…”

Section: Discussionmentioning

confidence: 99%

Comparison of functional activation responses from the auditory cortex derived using multi-distance frequency domain and continuous wave near-infrared spectroscopy

et al. 2021

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. Significance: Quantitative measurements of cerebral hemodynamic changes due to functional activation are widely accomplished with commercial continuous wave (CW-NIRS) instruments despite the availability of the more rigorous multi-distance frequency domain (FD-NIRS) approach. A direct comparison of the two approaches to functional near-infrared spectroscopy can help in the interpretation of optical data and guide implementations of diffuse optical instruments for measuring functional activation. Aim: We explore the differences between CW-NIRS and multi-distance FD-NIRS by comparing measurements of functional activation in the human auditory cortex. Approach: Functional activation of the human auditory cortex was measured using a commercial frequency domain near-infrared spectroscopy instrument for 70 dB sound pressure level broadband noise and pure tone (1000 Hz) stimuli. Changes in tissue oxygenation were calculated using the modified Beer–Lambert law (CW-NIRS approach) and the photon diffusion equation (FD-NIRS approach). Results: Changes in oxygenated hemoglobin measured with the multi-distance FD-NIRS approach were about twice as large as those measured with the CW-NIRS approach. A finite-element simulation of the functional activation problem was performed to demonstrate that tissue oxygenation changes measured with the CW-NIRS approach is more accurate than that with multi-distance FD-NIRS. Conclusions: Multi-distance FD-NIRS approaches tend to overestimate functional activation effects, in part due to partial volume effects.

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