Validity and reliability of velocity measurements on ultrasonography using custom software with an optical-flow...

Area of Science:

• Biomechanics
• Medical Imaging
• Software Validation

Background:

• Accurate measurement of muscle velocity is crucial for understanding muscle function and diagnosing neuromuscular disorders.
• Existing methods for measuring muscle velocity may have limitations in accuracy or accessibility.

Purpose of the Study:

• To validate a commercial software program employing an optical-flow algorithm for muscle movement velocity measurement.
• To identify optimal parameters for image quality, region of interest (ROI) size, and ROI location for accurate muscle velocity assessment.

Main Methods:

• A pork thigh muscle sample was subjected to controlled pulling at various velocities.
• Measurements were acquired using an accelerometer, high-velocity camera, and ultrasonography with Echolizer software.
• The influence of ROI characteristics and image settings (brightness, contrast) on measurement accuracy was analyzed.

Main Results:

• A regression equation (y=1.150 × -0.071) with a high determination coefficient (0.996) was established.
• The software demonstrated high accuracy with an average absolute error of 0.02 mm/s and average relative error of 0.20% for velocities between 2.5 and 16.5 mm/s.
• Measurement accuracy decreased with larger ROIs, inclusion of poor-quality image areas, or deeper muscle zones.

Conclusions:

• The custom software program, when utilizing the derived regression equation, offers a valid and reliable method for measuring muscle velocity.
• Optimal accuracy is achieved by carefully selecting ROIs to exclude deep tissues, poorly visualized areas, and by ensuring appropriate image brightness and contrast settings.