Increasing the field-of-view of dynamic cardiac OCT via post-acquisition mosaicing without affecting frame-rate or spatial resolution

Optical coherence tomography (OCT) allows imaging dynamic structures and fluid flow within scattering tissue, such as the beating heart and blood flow in murine embryos. For any given system, the frame rate, spatial resolution, field-of-view (FOV), and signal-to-noise ratio (SNR) are interconnected: favoring one aspect limits at least one of the others due to optical, instrumentation, and software constraints. Here we describe a spatio-temporal mosaicing technique to reconstruct high-speed, high spatial-resolution, and large-field-of-view OCT sequences. The technique is applicable to imaging any cyclically moving structure and operates on multiple, spatially overlapping tiled image sequences (each sequence acquired sequentially at a given spatial location) and effectively decouples the (rigid) spatial alignment and (non-rigid) temporal registration problems. Using this approach we reconstructed full-frame OCT sequences of the beating embryonic rat heart (11.5 days post coitus) and compared it to direct imaging on the same system, demonstrating a six-fold improvement of the frame rate without compromising spatial resolution, FOV, or SNR.