Improved utilization of frequency-domain data for optical tomographic imaging of the human brain

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openAccess

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Volume Title

A4 Artikkeli konferenssijulkaisussa

Date

2023

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Mcode

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Language

en

Pages

12
1-12

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Optical Tomography and Spectroscopy of Tissue XV, Progress in Biomedical Optics and Imaging - Proceedings of SPIE, Volume 12376

Abstract

Frequency-domain (FD) optical tomography instruments modulate the intensity of the light source at a radio frequency and measure the amplitude and phase shift of the detected photon density wave. The differing spatial sensitivities of amplitude and phase to the optical properties of tissue suggest that inclusion of phase data can improve the image reconstruction accuracy. This study describes our methodology for improved use of FD data in conjunction with a Monte Carlo (MC) forward solver (Monte Carlo eXtreme; MCX) and a voxel-based model of a two-year-old child’s head. The child participated our previous study where subjects were stimulated with affective (slow brushing) and non-affective touch (fast brushing) to their right forearm, and the responses were measured from the left hemisphere with our in-house 16-channel high-density FD system. We implemented the computation of the FD sensitivity profiles to the MCX photon simulation software, and validated the output against our in-house MC code. We used simulated and the real experimental touch response data to observe the effects of including both FD data types to the image reconstruction instead of amplitude data alone. For the simulated and experimental case, we observed that the inclusion of phase data increases the reconstructed contrast in the brain. The individual touch responses showed similarity to the group-level results in our original publication with 16 subjects and amplitude data alone, and other literature.

Description

Funding Information: We acknowledge the computational resources provided by the Aalto Science-IT project. Many thanks to the families participating the FinnBrain Birth Cohort Study. We also appreciate the following sources of funding: The Vilho, Yrjö and Kalle Väisälä Foundation of the Finnish Academy of Science and Letters (grant numbers 190017 and 200015 (to PH)), Academy of Finland (decisions 336788 and 336789 (to AH, NH and PH); 269282 (to IN); 273451 and 303937 (to IN); 134950 (to HK); 253270 (to HK)), Päivikki and Sakari Sohlberg Foundation (to IN), US National Institute of Health (NIH) award R01-GM114365 (to QF), Jane and Aatos Erkko Foundation (to HK and LK), Signe and Ane Gyllenberg Foundation (to HK and LK), State Research Grant (EVO) (to HK, LK and JJT), Hospital District of Southwest Finland State Research Grants (to JJT), Signe and Ane Gyllenberg Foundation (to JJT), Alfred Kordelin Foundation (to JJT), Sigrid Juselius Foundation (to JJT), Juho Vainio Foundation (to JJT), Finnish Medical Foundation (to JJT), and Emil Aaltonen Foundation (to JJT). Publisher Copyright: © 2023 SPIE.

Keywords

Affective touch, Atlas model, Diffuse optical tomography, Frequency-domain, Image reconstruction, Monte Carlo, Regularization, Toddler brain

Other note

Citation

Hirvi, P, Nissilä, I, Maria, A, Fang, Q, Kotilahti, K, Heiskala, J, Tuulari, J J, Karlsson, L, Hannukainen, A, Karlsson, H & Hyvönen, N 2023, Improved utilization of frequency-domain data for optical tomographic imaging of the human brain . in S Fantini & P Taroni (eds), Optical Tomography and Spectroscopy of Tissue XV ., 123760A, Progress in Biomedical Optics and Imaging - Proceedings of SPIE, vol. 12376, SPIE, pp. 1-12, Optical Tomography and Spectroscopy of Tissue, San Francisco, California, United States, 30/01/2023 . https://doi.org/10.1117/12.2649042