Doppler Optical Coherence Tomography in Cardiovascular Applications 1

The study of flow dynamics in complex geometry vessels is highly important in various biomedical applications where the knowledge of the mechanic interactions between the moving fluid and the housing media plays a key role for the determination of the parameters of interest, including the effect of blood flow on the possible rupture of atherosclerotic plaques. Doppler Optical Coherence Tomography (DOCT), as a functional extension of Optical Coherence Tomography (OCT), is an optic, noncontact, noninvasive tech� nique able to achieve detailed analysis of the flow/vessel interactions. It allows simultaneous high resolution imaging (~10 µm typical) of the morphology and composition of the vessel and determination of the flow velocity distribution along the measured crosssection. We applied DOCT system to image highresolution onedimensional and multidimensional velocity dist ribution profiles of Newtonian and nonNewtonian fluids flowing in vessels with complex geometry, including Yshaped and Tshaped vessels, vessels with aneur� ism, bifurcated vessels with deployed stent and scaffolds. The phantoms were built to mimic typical shapes of human blood vessels, enabling preliminary analysis of the interaction between flow dynamics and the (com� plex) geometry of the vessels and also to map the related velocity profiles at several inlet volume flow rates. Feasibility studies for quantitative observation of the turbulence of flows arising within the complex geometry vessels are discussed. In addition, DOCT technique was also applied for monitoring cerebral mouse blood flow in vivo. Twodimensional DOCT images of complex flow velocity profiles in blood vessel phantoms and in vivo subcranial mouse blood flow velocities distributions are presented.