Instrument-independent flux units for laser doppler perfusion monitoring assessed in a multi-device study on the renal cortex

• Published in: Microvascular research 2003-09, Vol.66 (2), p.83-90
• Main Authors: Petoukhova, A.L, Steenbergen, W, Morales, F, Graaff, R, de Jong, E.D, Elstrodt, J.M, de Mul, F.F.M, Rakhorst, G
• Format: Article
• Language: English
• Subjects: Animals; Arterial and mild venous constriction; Biological and medical sciences; Blood Flow Velocity - physiology; Brownian motion; Feasibility Studies; Fundamental and applied biological sciences. Psychology; Kidney cortex; Kidney Cortex - blood supply; Laser Doppler perfusion monitoring; Laser-Doppler Flowmetry - instrumentation; Laser-Doppler Flowmetry - methods; Laser-Doppler Flowmetry - standards; Monitoring, Physiologic; Perfusion; Perfusion units; Reference Values; Regional Blood Flow; Standardization; Swine; Ultrasonic arterial flow meter; Vertebrates: urinary system
• ISSN: 0026-2862; 1095-9319
• DOI: 10.1016/S0026-2862(03)00036-0

To investigate the feasibility of instrument-independent perfusion units for laser Doppler flowmetry, a comparison was performed of two commercial fiberoptic laser Doppler perfusion monitors measuring the same flux situation for two different types of probes. In vivo measurements were performed on the cortex of pig’s kidney, with an ultrasonic arterial flow meter as reference. The flow was mainly varied by internal arterial constriction using a balloon catheter. For each probe, instruments are compared in terms of the ratio of laser Doppler flux and arterial flow. For a given probe, the flux-to-flow ratios of the two instruments show a linear mutual relationship for a wide variety of arterial flows and laser Doppler fluxes. In vitro measurements were performed on an aqueous suspension of polystyrene microspheres. For the probe with interfiber distance 500 μm the ratio of the in vivo fluxes appears to agree within 16% to the value found in vitro, while for the 250-μm probe a difference of 28% was found. For a wide range of fluxes, the in vivo flux values of one instrument can be translated into flux values for the other instrument, in spite of the instrumental differences. This enables the user to render experimental results independent of the specific instrument, thus facilitating multi-center studies.