Dual wavelength endoscopic laser speckle contrast imaging system for indicating tissue blood flow and oxygenation

We present a dual-wavelength endoscopic laser speckle contrast system including illumination with polarization maintaining fibres and imaging using a leached fibre image guide. This system has a frame rate of 10 Hz and can rapidly monitor changes in blood flow in vivo, including due to the heart beat, using the contrast values of the speckle images recorded with 1 ms exposure time. In addition the mean intensities can record the respiration period and can indicate changes in tissue oxygenation. This system was tested during an occlusion to a human finger and is being applied in endoscopy.