Directly measuring absolute flow speed by frequency-domain laser speckle imaging

Area of Science:

• Biomedical Optics
• Medical Imaging
• Physiology

Background:

• Laser speckle contrast imaging (LSCI) is a widely used technique for visualizing blood flow.
• Traditional LSCI faces challenges in quantitative analysis due to factors like illumination intensity and static tissue scattering, limiting accurate flow speed evaluation.
• Existing methods often rely on complex mathematical models for blood flow estimation, introducing potential inaccuracies.

Purpose of the Study:

• To introduce a novel frequency-domain laser speckle imaging (FDLSI) method.
• To demonstrate FDLSI's capability for direct measurement of absolute blood flow speed.
• To validate the accuracy and robustness of FDLSI compared to traditional LSCI.

Main Methods:

• Development and implementation of a frequency-domain laser speckle imaging system.
• Conducting phantom experiments to assess the accuracy of absolute flow speed measurements.
• Performing in vivo experiments to evaluate the method's performance under varying illumination conditions.

Main Results:

• FDLSI accurately measured absolute flow speed in phantom experiments, showing good agreement (within 10% deviation) with preset values.
• In vivo studies confirmed that FDLSI measurements were minimally influenced by changes in illumination intensity.
• The frequency-domain approach effectively addresses limitations of traditional LSCI in quantitative blood flow analysis.

Conclusions:

• Frequency-domain laser speckle imaging (FDLSI) provides a direct and quantitative method for measuring absolute blood flow speed.
• FDLSI overcomes key limitations of conventional LSCI, offering improved accuracy and reliability.
• This technique holds significant potential for advanced biomedical research and clinical applications requiring precise blood flow assessment.