Newsletter 2019.2 Index
Theme : "Mechanical Engineering Congress, 2018 Japan (MECJ-18)"
Micro-tomographic Visualization of Capillary Blood Flow Velocity using Multi-Functional Optical Coherence Tomography
The skin aging process, e.g. wrinkles and saggings, caused by not only aging but also ultraviolet irradiation, could be related to the depression of metabolic function. The microcirculation system should be an important guideline of skin care for the anti/smart-aging. Rheological behavior of interstitial in epidermal and dermal tissue, including blood micro-circulation, can vary skin mechanics in micro scale, i.e. visco-elasticity. Therefore, an in vivo quantitative measurement of capillary blood flow velocity is crucial to clarify their properties. The purpose of this study is to visualize the tomographic flow velocity of red blood cell in capillaries below the epidermal skin using Optical Coherence Doppler Velocigraphy, i.e. OCDV. This is constructed on a low coherence interferometer, which is based on Hilbert transform and adjacent auto-correlation. In order to validate OCDV system, this was in vivo applied to ear skin of mouse. As a result of skin tomography obtained by OCDV, en face cross-sectional imaging of doppler velocity was found to display networks of capillary blood vessels in upper dermal tissue, as well as morphological skin structure. It was confirmed that capillary vasculature and blood velocity can be visualized tomographically even in the upper subpapillary layer. In summary, OCDV system could be quite useful for a micro-tomographic imaging of blood flow velocity of capillary vessels inside skin.
Optical Coherence Tomography (OCT), Optical Coherence Doppler Velocigraphy (OCDV), Microcirculation, Blood flow velocity measurement, Hilbert Transform, Adjacent Auto-Correlation, Flow-modulated Doppler frequency, Skin Mechanics
Fig. 1 3-dimensional morphological image of a mouse ear obtained by OCDV.
Fig. 2 2-dimensional en face tomographic visualization of capillary blood velocity of a mouse ear obtained by OCDV.