Laser speckle contrast imaging for assessing flow velocities and scatterer concentration in capillary phantoms

Imaging of tissue perfusion is a vital tool in assessing the status of various diseases that are reflected in the microcirculation. Different techniques developed for imaging microcirculation as well as assessing red blood cell (RBC) concentration are lacking quantitative flow information, whole field imaging capability and non invasiveness. This paper reports on a whole field, non invasive laser speckle imaging technique to quantitatively assess the capillary flow variations and scatterer concentration using microcirculation phantoms. A capillary phantom has been fabricated on two perspex sheets of 12mm thickness each. The flow channels of depth 0.7 and 2mm were machined in the sheets and blood mimicking phantom solution of desired concentration was pumped using a syringe infusion pump (RH-SY10, Ravel Hitecks, India) to get the desired flow rate. The phantom was illuminated with a He Ne laser (ThorLabs) and the resulting speckle pattern was captured using a CCD camera and frame grabber card and the images were analysed using the developed algorithm. The experimental set up is shown in Fig.1.