Measurements of blood flow velocity in the microcirculation

A method for the measurement of red blood cell velocity in the microcirculation is described. The technique is based on the on-line cross-correlation of the delay between optical signatures derived from photodetectors aligned in direction oflow. A specialised photodiode holder which can be inserted directly in place of an ocular is described. The interdetector delay data is computed automatically from the cross-correlation function by a peak detector designed to provide a voltage proportional to the delay to maximum cross-correlation, regardless of intermediate lower peaks. Application of this system to measurements in the rabbit ear chamber, mesentery and skeletal muscle is described.