title: Normalization of vasomotion in laser Doppler perfusion monitoring.
abstract: Laser Doppler flux signals show temporal fluctuations caused by physiological phenomena like heartbeat, respiration, and local variation of vascular tonus, vasomotion. This study investigates the influence of fiber arrangement, equipment and two probe locations on the variations in laser Doppler flux signals in five frequency bands in the absence of provocations. Two probes with detecting optical fibers at several distances from the illuminating source were used, as well as instruments from two manufacturers. The results show that normalization of the filtered flux signals with the mean flux leads to an enormous decrease of the influence of fiber distance. The difference between instruments is small after normalization. Some influence of probe location remains after normalization. Development of a standard method for normalization of the variations in laser Doppler signals is recommended.
authors.affiliation: University Medical Center Groningen, University of Groningen, Dept. of Biomedical Engineering, Groningen, The Netherlands. r.graaff@med.umcg.nl
authors.forename: Reindert
authors.initials: R
authors.lastname: Graaff
authors.forename: Fernando
authors.initials: F
authors.lastname: Morales
authors.forename: Andries J
authors.initials: AJ
authors.lastname: Smit
authors.forename: Ed D
authors.initials: ED
authors.lastname: de Jong
authors.forename: Frits F M
authors.initials: FF
authors.lastname: de Mul
authors.forename: Gerhard
authors.initials: G
authors.lastname: Rakhorst
mesh_terms: D005336:Fiber Optic Technology / Q000379:methods; D006801:Humans; D017078:Laser-Doppler Flowmetry / Q000295:instrumentation* / Q000379:methods*; D009200:Myocardial Contraction; D015588:Observer Variation; D055100:Optical Fibers; D015656:Respiratory Mechanics