title: Time-resolved multidistance near-infrared spectroscopy of the adult head: intracerebral and extracerebral absorption changes from moments of distribution of times of flight of photons.
abstract: We report on multidistance time-resolved diffuse reflectance spectroscopy of the head of a healthy adult after intravenous administration of a bolus of indocyanine green. Intracerebral and extracerebral changes in absorption are deduced from moments (integral, mean time of flight, and variance) of the distributions of times of flight of photons (DTOFs), recorded simultaneously at four different source-detector separations. We calculate the sensitivity factors converting depth-dependent changes in absorption into changes of moments of DTOFs by Monte Carlo simulations by using a layered model of the head. We validate our method by analyzing moments of DTOFs simulated for the assumed changes in absorption in different layers of the head model.
authors.affiliation: Physikalisch-Technische Bundesanstalt, Abbestrasse 2-12, 10587 Berlin, Germany.
authors.forename: Adam
authors.initials: A
authors.lastname: Liebert
authors.forename: Heidrun
authors.initials: H
authors.lastname: Wabnitz
authors.forename: Jens
authors.initials: J
authors.lastname: Steinbrink
authors.forename: Hellmuth
authors.initials: H
authors.lastname: Obrig
authors.forename: Michael
authors.initials: M
authors.lastname: Möller
authors.forename: Rainer
authors.initials: R
authors.lastname: Macdonald
authors.forename: Arno
authors.initials: A
authors.lastname: Villringer
authors.forename: Herbert
authors.initials: H
authors.lastname: Rinneberg
mesh_terms: D000465:Algorithms; D001783:Blood Flow Velocity; D001921:Brain / Q000098:blood supply* / Q000378:metabolism*; D002560:Cerebrovascular Circulation; D003936:Diagnosis, Computer-Assisted / Q000379:methods*; D006257:Head / Q000098:blood supply / Q000502:physiology; D006801:Humans; D007201:Indicator Dilution Techniques; D007208:Indocyanine Green / Q000493:pharmacokinetics*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013055:Spectrophotometry, Infrared / Q000295:instrumentation / Q000379:methods*
chemical_list: D007208:Indocyanine Green