Overview of experimental method.

<p>Schematic representation of optical paths for in the vivo flow measurement: <i>(left)</i> using fluorescent tracers illuminated by a pulsed laser and <i>(middle)</i> using red blood cells illuminated by a pulsed LED. <i>(right)</i> A typical result of the measurements: a composite image of the PIV results for the fluorescent tracer particles (top) and red blood cells (bottom).