High resolution laser Doppler perfusion imaging for the investigation of blood circulatory changes after microdialysis probe insertion.

Abstract

Cutaneous microdialysis enables in vivo sampling of substances in the extracellular space in human skin. It is usual to allow an equilibration time to elapse after tissue trauma caused by probe insertion. One of the prerequisites for correct interpretation of data is detailed knowledge of the effect of insertion and presence of the probe in the skin, especially in the tissue closest to the membrane. Laser Doppler perfusion imaging was used to investigate the time required for blood perfusion to return to near normal levels after probe insertion. The standard system was used in parallel with a high resolution system. The latter gave 3600 measurement sites in an area of 2 cm × 2 cm and thus enabled a detailed study of circulatory changes immediately around the membrane. Perfusion levels prior to probe insertion as well as the perfusion response to probe insertion were recorded by both systems. In agreement with previous findings, the perfusion levels were found to return to near normal levels within 60 min. Individual variations were, however, seen. High resolution laser Doppler perfusion imaging provided detailed visualisation of these variations both spatially and over time. High resolution laser Doppler perfusion imaging is superior to standard laser Doppler perfusion imaging in detailed visualisation of the variations in skin blood perfusion after microdialysis probe insertion. The individual variations seen can be of importance in the interpretation of microdialysis data.