title: Effects of assuming constant optical scattering on haemoglobin concentration measurements using NIRS during a Valsalva manoeuvre.
abstract: Resolving for changes in concentration of tissue chromophores in the human adult brain with near-infrared spectroscopy has generally been based on the assumption that optical scattering and pathlength remain constant. We have used a novel hybrid optical spectrometer that combines multi-distance frequency and broadband systems to investigate the changes in scattering and pathlength during a Valsalva manoeuvre in 8 adult volunteers. Results show a significant increase in the reduced scattering coefficient of 17% at 790nm and 850nm in 4 volunteers during the peak of the Valsalva. However, these scattering changes do not appear to significantly affect the differential pathlength factor and the tissue haemoglobin concentration measurements.
authors: Biomedical Optics Research Laboratory, Department of Medical Physics and Bioengineering, University College London, Gower Street, London WC1E 6BT, UK.
authors: Lei
authors: L
authors: Gao
authors: Clare E
authors: CE
authors: Elwellelwell
authors: Matthias
authors: M
authors: Kohl-Bareis
authors: Marcus
authors: M
authors: Gramer
authors: Chris E
authors: CE
authors: Cooper
authors: Terence S
authors: TS
authors: Leung
authors: Ilias
authors: I
authors: Tachtsidis
mesh_terms: D000328:Adult; D001921:Brain / Q000378:metabolism*; D005260:Female; D006454:Hemoglobins / Q000032:analysis*; D006801:Humans; D008297:Male; D019265:Spectroscopy, Near-Infrared; D014636:Valsalva Maneuver; D055815:Young Adult
chemical_list: D006454:Hemoglobins