Imaging of flow velocity profiles within the complex geometry vessels by Doppler Optical Coherence Tomography

摘要

Doppler Optical Coherence Tomography (DOCT) technique was applied to non-invasive monitoring of cross-sectional velocity profiles distributions within complex geometry vessels. A set of micro vessels of different diameters with T-shaped and Y-shaped bifurcation and vessels with aneurysm were built. The shape of the vessel was chosen to mimic human vessel shapes of similar characteristics. Intralipid, set in motion at constant input volume flow rate by a syringe pump, was used in the experiments. The influence of vessels geometry, including bifurcation (T- and Y- junctions) and the aneurysms. on the flow dynamics under different inlet flow rates was studied. We show that under constant input volume flow rate, the flow velocities distribution measured along a cross-sectional plane orthogonal to the inlet arm. located at 20 mm off the junction, exhibited stationary and laminar behaviour. A non-homogeneous distribution of flow velocity along a cross-sectional plane located at the junction was observed. The relation between the acquired velocity distribution and the vessel geometry is analyzed. The feasibility of DOCT for mapping the velocity profiles along the vessels junction with a spatial resolution of about 10 × 10 × l0 μm~3 and a minimum detectable velocity of about 2 mrn·s~(-1)'is presented.