Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2019 Apr 30;10(5):2657-2669.
doi: 10.1364/BOE.10.002657. eCollection 2019 May 1.

Self-calibrating time-resolved near infrared spectroscopy

Stanislaw Wojtkiewicz  1 , Anna Gerega  2 , Marta Zanoletti  3 , Aleh Sudakou  2 , Davide Contini  3 , Adam Liebert  2 , Turgut Durduran  4   5 , Hamid Dehghani  1
Affiliations

Self-calibrating time-resolved near infrared spectroscopy

Stanislaw Wojtkiewicz et al. Biomed Opt Express. .

Abstract

Time-resolved near infrared spectroscopy is considered to be a gold standard technique when measuring absolute values of tissue optical properties, as it provides separable and independent information about both tissue absorption and scattering. However, time-resolved instruments require an accurate characterization by measuring the instrument response function in order to decouple the contribution of the instrument itself from the measurement. In this work, a new approach to the methodology of analysing time-resolved data is presented where the influence of instrument response function is eliminated from the data and a self-calibrating analysis is proposed. The proposed methodology requires an instrument to provide at least two wavelengths and allows spectral parameters recovery (optical properties or constituents concentrations and reduced scatter amplitude and power). Phantom and in-vivo data from two different time-resolved systems are used to validate the accuracy of the proposed self-calibrating approach, demonstrating that parameters recovery compared to the conventional curve fitting approach is within 10% and benefits from introducing a spectral constraint to the reconstruction problem. It is shown that a multi-wavelength time-resolved data can be used for parameters recovery directly without prior calibration (instrument response function measurement).

PubMed Disclaimer

Conflict of interest statement

The authors declare that there are no conflicts of interest related to this article. LUCA project involves industrial collaboration and, as such, potential conflicts of interest are being monitored by relevant institutional bodies. None has been identified to date.

Figures

Fig. 1
Fig. 1
Instrument response functions (IRF) of POLIMI [24] and IBIB [25] time-resolved multi-wavelength instruments. Time domain (a-b) as measured, frequency domain amplitude (c-d) and phase (e-f) at all wavelengths. All IRFs are normalized by their integral and maxima are aligned in time. The 1% of maximum threshold in panels (a-b) is used for visualization purposes.
Fig. 2
Fig. 2
Temporal point spread functions (TPSF) in time domain (TPSF(t)) and phase shift of their frequency components (TPSF(ω)) as calculated for a semi-infinite model. rsd – source-detector separation, Tmax – time of the TPSF maximum, ⟨t⟩ - mean time of flight of photons. The phase shift in radians is converted to time. The TPSF amplitude is arbitrary.
Fig. 3
Fig. 3
Time-resolved simulated DTOFs in time domain (a) and in frequency domain (b-c) normalized as shown in Eq. (4).
Fig. 4
Fig. 4
Parameters recovered from time-resolved data using time (utilising IRF) and frequency (no IRF used) domain approaches. Recovered tissue constituents and scattering (1st row) and recovery errors (2nd – 3rd rows). Statistics created for 30 runs of data generation/recovery procedures.
Fig. 5
Fig. 5
Solid phantom parameters recovered from time-resolved data using curve fitting in time domain (utilising IRF) and the frequency domain approach (no IRF used as in Eq. (4)).
Fig. 6
Fig. 6
Optical properties and tissue constituents as measured on a forearm during an arm occlusion (systolic pressure + 50 mmHg). Parameters recovered from time-resolved data using time (utilizing IRF) and frequency (no IRF used) domain approaches. To preserve clarity only 3 of 14 available wavelengths are shown (first, centre and last).
See this image and copyright information in PMC

References

    1. Pifferi A., Contini D., Mora A. D., Farina A., Spinelli L., Torricelli A., “New frontiers in time-domain diffuse optics, a review,” J. Biomed. Opt. 21(9), 091310 (2016).10.1117/1.JBO.21.9.091310 - DOI - PubMed
    1. Torricelli A., Contini D., Pifferi A., Caffini M., Re R., Zucchelli L., Spinelli L., “Time domain functional NIRS imaging for human brain mapping,” Neuroimage 85(Pt 1), 28–50 (2014).10.1016/j.neuroimage.2013.05.106 - DOI - PubMed
    1. Wabnitz H., Moeller M., Liebert A., Obrig H., Steinbrink J., Macdonald R., “Time-resolved near-infrared spectroscopy and imaging of the adult human brain,” Adv. Exp. Med. Biol. 662, 143–148 (2010).10.1007/978-1-4419-1241-1_20 - DOI - PubMed
    1. Konugolu Venkata Sekar S., Farina A., Dalla Mora A., Lindner C., Pagliazzi M., Mora M., Aranda G., Dehghani H., Durduran T., Taroni P., Pifferi A., “Broadband (550-1350 nm) diffuse optical characterization of thyroid chromophores,” Sci. Rep. 8(1), 10015 (2018).10.1038/s41598-018-27684-8 - DOI - PMC - PubMed
    1. Farina A., Torricelli A., Bargigia I., Spinelli L., Cubeddu R., Foschum F., Jäger M., Simon E., Fugger O., Kienle A., Martelli F., Di Ninni P., Zaccanti G., Milej D., Sawosz P., Kacprzak M., Liebert A., Pifferi A., “In-vivo multilaboratory investigation of the optical properties of the human head,” Biomed. Opt. Express 6(7), 2609–2623 (2015).10.1364/BOE.6.002609 - DOI - PMC - PubMed

LinkOut - more resources