Measuring blood velocity using correlative spectrally encoded flow cytometry.

Spectrally encoded flow cytometry (SEFC) is a promising technique for imaging blood in the microcirculation. Yet, the dependency of one of the axes of the image on time prevents effective quantification of essential clinical parameters. Here, we address this challenge by splitting the optical path in an SEFC system into two parallel imaging lines, followed by straightforward data analysis for recovering the flow speed from the multiplexed data. The method is demonstrated by measuring the flow velocity of latex beads and blood cells in vitro. The system allows real-time velocity measurements of up to 11.7  mm/s at high spatial resolution, and could be integrated into existing SEFC systems for effectively measuring blood parameters in small capillary vessels.