High speed, wide velocity dynamic range Doppler optical coherence tomography (Part II):: Imaging in vivo cardiac dynamics of Xenopus laevis

We previously reported a Doppler optical coherence tomography (DOCT) system design [1] for high-speed imaging with wide velocity dynamic range (up to 28.5 dB when acquiring 8 frames per second), operating at 1.3 mum with a coherence length of 13.5 mum. Using a developmental biology model (Xenopus laevis), here we test the DOCT system's ability to image cardiac dynamics in an embryo in vivo, with a simple hand-held scanner at 4 similar to 16 frames per second. In particular, we show that high fidelity DOCT movies can be obtained by increasing the reference arm scanning rate (similar to 8 kHz). Utilizing a combination of four display modes (B-mode, color-Doppler, velocity variance, and Doppler spectrum), we show that DOCT can detect changes in velocity distribution during heart cycles, measure the velocity gradient in the embryo, and distinguish blood flow Doppler signal from heart wall motions. (C) 2003 Optical Society of America.