Assessment of microvasculature flow state with a high speed all-optic dual-modal system of optical coherence tomography and photoacoustic imaging.

We propose a high speed all-optic dual-modal system that combines spectral domain optical coherence tomography (SDOCT) and photoacoustic imaging (PAI) to evaluate microvasculature flow states. A homodyne interferometer was used to remotely detect the surface vibration caused by photoacoustic (PA) waves. The PA excitation, PA probing and SDOCT probing beams share the same X-Y galvanometer scanner to perform fast two-dimensional scanning. In addition, we introduced multi-excitation, dual-channel acquisition and sensitivity compensation to improve the imaging speed of the PAI sub-system. The total time for imaging a sample with 256 × 256 pixels is less than 1 minute. The performance of the proposed system was verified by in vivo imaging of the vascular system in a mouse pinna with normal and then blocked blood circulations. The experimental results indicate that the proposed system is capable of revealing different blood flow states (static and moving) and is useful for the study of diseases related to functional blood supply.