title: Separation of superficial and cerebral hemodynamics using a single distance time-domain NIRS measurement.
abstract: In functional near-infrared spectroscopy (fNIRS) superficial hemodynamics can mask optical signals related to brain activity. We present a method to separate superficial and cerebral absorption changes based on the analysis of changes in moments of time-of-flight distributions and a two-layered model. The related sensitivity factors were calculated from individual optical properties. The method was validated on a two-layer liquid phantom. Absorption changes in the lower layer were retrieved with an accuracy better than 20%. The method was successfully applied to in vivo data and compared to the reconstruction of homogeneous absorption changes.
authors.affiliation: Physikalisch-Technische Bundesanstalt (PTB), Abbestr. 2-12, 10587, Berlin, Germany.
authors.forename: Alexander
authors.initials: A
authors.lastname: Jelzow
authors.affiliation: Physikalisch-Technische Bundesanstalt (PTB), Abbestr. 2-12, 10587, Berlin, Germany.
authors.forename: Heidrun
authors.initials: H
authors.lastname: Wabnitz
authors.affiliation: University College London, Dept. Med. Physics and Bioengineering, Gower Street, London WC1E 6BT, UK.
authors.forename: Ilias
authors.initials: I
authors.lastname: Tachtsidis
authors.affiliation: Free Univ. Berlin, Habelschwerdter Allee 45, 14195 Berlin, Germany.
authors.forename: Evgeniya
authors.initials: E
authors.lastname: Kirilina
authors.affiliation: Physikalisch-Technische Bundesanstalt (PTB), Abbestr. 2-12, 10587, Berlin, Germany.
authors.forename: Rüdiger
authors.initials: R
authors.lastname: Brühl
authors.affiliation: Physikalisch-Technische Bundesanstalt (PTB), Abbestr. 2-12, 10587, Berlin, Germany.
authors.forename: Rainer
authors.initials: R
authors.lastname: Macdonald
keywords: (120.3890) Medical optics instrumentation; (170.1470) Blood or tissue constituent monitoring; (170.3880) Medical and biological imaging; (170.5280) Photon migration; (170.6510) Spectroscopy, tissue diagnostics; (170.6920) Time-resolved imaging