A laser speckle contrast imaging system to study blood flow dynamics in the rodent brain

Abstract

Optical imaging modalities have become increasingly prevalent in biomedical research for discerning functional and anatomical information. Laser Speckle Contrast Imaging (LSCI) is a non-invasive full-field optical imaging technique that gives a 2-D microcirculatory surface flow map within live tissue. LSCI is based on the grainy image produced by a laser light illuminating an object, known as a speckle pattern. The visual appearance of the speckle pattern produced by objects showing some kind of activity, such as flowing red blood cells (RBCs) is called a dynamic speckle. LSCI makes use of statistical analysis of the dynamic speckle pattern which is modulated by the speed information of the RBCs. The main setup of a LSCI consists of a 632 nm red laser, an optical imaging system and a CCD camera connected to a PC. LSCI is mainly used in pre-clinical studies by neuroscientists for CBF dynamics and in clinical examinations for blood perfusion imaging of the retina and the skin, for example during examination of burns.