Skeletal Muscle Echo Intensity Values Differ Significantly across Ultrasound Parameter Settings

Area of Science:

• Musculoskeletal Ultrasound
• Muscle Physiology
• Biomedical Imaging

Background:

• Muscle quality assessment is crucial for understanding muscle health.
• Ultrasound echo intensity (EI) is a promising, non-invasive metric for muscle quality.
• Standardization of ultrasound parameters is needed for reliable EI measurements.

Purpose of the Study:

• To investigate the influence of adjustable ultrasound parameter settings on echo intensity (EI) values.
• To determine the relationship between specific ultrasound settings and EI in lower limb and trunk muscles.
• To provide recommendations for optimizing ultrasound parameter settings for consistent muscle quality assessment.

Main Methods:

• A repeated measures cross-sectional study involving 21 middle-aged participants.
• Rectus femoris, gracilis, and rectus abdominis muscles were scanned using a Mindray M7 premium ultrasound machine.
• Adjustable parameters (dynamic range, gray map, line density, persistence, IClear) were varied across their full range, while gain, depth, and frequency remained fixed.

Main Results:

• Significant correlations were found between dynamic range, gray map, IClear, and EI values in all tested muscles (r_rm: -0.86 to 0.45).
• Echo intensity values showed significant differences across the tested ranges of dynamic range (p < 0.013), gray map (p < 0.003), and IClear (p < 0.003).
• These relationships were consistent across rectus femoris, gracilis, and rectus abdominis muscles.

Conclusions:

• Ultrasound echo intensity is significantly influenced by machine parameter settings in middle-aged adults.
• To ensure reliable muscle quality assessment using EI, it is recommended to standardize and fix ultrasound parameter settings, preferably within their midrange.
• Consistent parameter selection is vital to minimize variability and enhance the diagnostic accuracy of ultrasound-based muscle quality evaluation.