Feasibility of Speckle Contrast Optical Spectroscopy for Quantifying Active Muscle Blood Flow

The quantification of muscle blood flow is crucial in fields such as exercise physiology and rehabilitation medicine. While diffuse correlation spectroscopy (DCS) is a well-established, noninvasive method for measuring tissue blood flow, its widespread use is hindered by the need for expensive photon counters and its relatively low signal-to-noise ratio (SNR). Speckle contrast optical spectroscopy (SCOS), a novel technique utilizing a megapixel camera (e.g., a complementary metal- oxide-semiconductor camera), has emerged as a promising alternative. This method utilizes spatial speckle contrast to measure blood flow, offering a higher SNR at a reduced cost. This study evaluates the feasibility of SCOS in quantifying muscle blood flow under active conditions and compares its performance directly with that of DCS. The results indicate that SCOS is consistent with DCS in terms of relative blood flow index measurements, and its SNR surpasses that of DCS, particularly in detecting pulsatile blood flow. These findings position SCOS as a cost-effective, high-precision tool for monitoring skeletal muscle microcirculation during physical activities, potentially enhancing clinical and research applications in vascular function assessment.Clinical Relevance- SCOS presents a cost-effective alternative to DCS for the assessment of blood flow in active muscles, offering a superior SNR and enhanced detection of pulsatile flow. This advantage makes it valuable for evaluating vascular function in exercise physiology and rehabilitation contexts.