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Journal of Biomedical Optics • Open Access

Microcirculation assessment using an individualized model for diffuse reflectance spectroscopy and conventional laser Doppler flowmetry
Author(s): Tomas Strömberg; Hanna Karlsson; Ingemar Fredriksson; Fredrik H. Nyström; Marcus Larsson

Paper Abstract

Microvascular assessment would benefit from co-registration of blood flow and hemoglobin oxygenation dynamics during stimulus response tests. We used a fiber-optic probe for simultaneous recording of white light diffuse reflectance (DRS; 475–850 nm) and laser Doppler flowmetry (LDF; 780 nm) spectra at two source-detector distances (0.4 and 1.2 mm). An inverse Monte Carlo algorithm, based on a multiparameter three-layer adaptive skin model, was used for analyzing DRS data. LDF spectra were conventionally processed for perfusion. The system was evaluated on volar forearm recordings of 33 healthy subjects during a 5-min systolic occlusion protocol. The calibration scheme and the optimal adaptive skin model fitted DRS spectra at both distances within 10%. During occlusion, perfusion decreased within 5 s while oxygenation decreased slowly (mean time constant 61 s; dissociation of oxygen from hemoglobin). After occlusion release, perfusion and oxygenation increased within 3 s (inflow of oxygenized blood). The increased perfusion was due to increased blood tissue fraction and speed. The supranormal hemoglobin oxygenation indicates a blood flow in excess of metabolic demands. In conclusion, by integrating DRS and LDF in a fiber-optic probe, a powerful tool for assessment of blood flow and oxygenation in the same microvascular bed has been presented.

Paper Details

Date Published: 1 May 2014
PDF: 6 pages
J. Biomed. Opt. 19(5) 057002 doi: 10.1117/1.JBO.19.5.057002
Published in: Journal of Biomedical Optics Volume 19, Issue 5
Show Author Affiliations
Tomas Strömberg, Linköping Univ. (Sweden)
Hanna Karlsson, Linköping Univ. (Sweden)
Ingemar Fredriksson, Linköping Univ. (Sweden)
Perimed AB (Sweden)
Fredrik H. Nyström, Linköping Univ. (Sweden)
Marcus Larsson, Linköping Univ. (Sweden)

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