Tissue motion – a disturbance in the laser-Doppler blood flow signal?

Article type: Research Article

Authors: Öberg, P.Å.^{; *}

Affiliations: Department of Biomedical Engineering, Linköpings Universitet, Linköping, Sweden

Correspondence: [*] Correspondence: Prof. P.Å. Öberg, Department of Biomedical Engineering, Linköping University, S-581 85 Linköping, Sweden. Tel.: +46 13 222460; Fax: +46 13 101902; E-mail: [email protected].

Abstract: The tissue matrix in the human body is continuously in motion driven by forces generated by the circulatory and respiratory systems. The linear velocities recorded can be as high as 300 μm/s. The question raised: is the motion of tissue matrix generating an error signal in laser-Doppler (LD) recordings that is misinterpreted as solely a blood flow signal. The problem is studied by using a physical model demonstrating the contribution from a flow channel and, in addition, from a linear motion of the flow tube. Measurements of skin motion in the forearm have been performed. The corresponding spectra have been compared with blood flow spectra recorded with the LD method at the same sites. The two types of spectra overlap each other indicating that motion induced signals can be interpreted as a flow signal. The “blood flow” contribution from tissue motion varies strongly with the site studied.

Keywords: Laser-Doppler, tissue motion, disturbance, blood flow signal, velocity spectrum, Doppler spectrum

DOI: 10.3233/THC-1999-72-309

Journal: Technology and Health Care, vol. 7, no. 2-3, pp. 185-192, 1999