In vivo cell tracking using speckle image correlation technique employing high frame rate confocal laser scanning microscopy in a mouse skin model

Particle image velocimetry is a technique for analyzing and visualizing collective velocity using sequential images of moving particles. However, there still exist tracer seeding problems in in vivo measurement applications. For overcoming this limitation cell tracking based on speckle image cross-correlation method to confocal microscopy, it is possible to analyze the velocity of cells in blood flow without injecting exogenous particles. Using a standard rate of 30 fps allows tracking of hematocytes near 200μm / sec, but this is insufficient at only moderately higher flow rates due to the inclusion of individual cells moving at velocities well above the average. It is necessary to overcome this limitation by using higher frame rates of imaging for a precise blood stream analysis. We performed in vivo cell tracking based on speckle image cross-correlation acquired at rates of 30, 90 and 180 fps using a confocal microscope. We found that the more than 5-fold increase in frame rate achieves a similar low rate of errors for blood flow containing cells moving at an average speed of up to to 1 mm/sec.