Noninvasive In-vivo Measurements of Microvessels by Reflection-Type Micro Multipoint Laser Doppler Velocimeter

Abstract

We have developed a micro multipoint laser Doppler velocimeter (µ-MLDV) that enables selective collection of Doppler interference photons. In previous report [H. Ishida et al.: Rev. Sci. Instrum. 82 (2011) 076104], developed the reflection-type µ-MLDV, and showed the results of demonstrations performed on transparent artificial flow channels. In this study, we attempted to perform in-vivo experiments using animals. It can measure absolute velocity and generate tomographs of blood vessels courses. The present system can perform noninvasive in-vivo measurements with a detection limit of about 0.5 mm/s and a spatial resolution in the x–y plane of 125 µm. It is thus able to image venulae. It was used to image venulae in a mouse ear and a subcutaneous blood vessel in a mouse abdomen at a depth of about 1.0 mm below the skin.