Laser speckle contrast imaging system using nanosecond pulse laser source

Abstract

Many diseases, such as cardiovascular diseases, atherosclerosis, diabetes, and chronic venous insufficiency, cause functional and morphological changes in blood flow.^1,2 The dynamic monitoring of blood flow has great value in life science research, drug evaluation, clinical diagnosis, clinical application, and surgical guidance. Currently, some effective measurement methods for living animal tissues, especially blood vessels, are being studied, such as magnetic resonance perfusion imaging, positron emission tomography (PET), x-ray angiography, fluorescence angiography, and laser Doppler flowmeter. However, there are some limitations in these blood flow imaging techniques.^{3 – 5} For example, magnetic resonance imaging (MRI) perfusion imaging and PET are mostly used for holistic imaging with low spatial and temporal resolution and high cost. Fluorescence angiography and x-ray angiography cannot provide functional information of blood flow and need injection of a contrast agent. Doppler flowmeter can only provide a single point of monitoring that does not provide a complete two-dimensional (2-D) map of blood flow velocity.^{6 – 9} Compared to other imaging techniques, laser speckle contrast imaging (LSCI) provides 2-D full-speed blood flow distribution with lower cost.