Testing the Reliability of a Procedure Using Shear-Wave Elastography for Measuring Longus Colli Muscle Stiffness

Area of Science:

• Musculoskeletal Ultrasound
• Biomechanics
• Medical Imaging

Background:

• Reproducible assessment of deep cervical muscle mechanics is crucial for clinical applications.
• The reliability of shear-wave elastography (SWE) for the longus colli (LC) muscle has not been previously established.
• Mechanical neck pain necessitates reliable methods for evaluating muscle function.

Purpose of the Study:

• To determine the intra- and inter-examiner reliability of LC stiffness measurements using SWE.
• To establish the reproducibility of SWE for assessing LC muscle mechanical properties.
• To validate a standardized SWE protocol for patients with mechanical neck pain.

Main Methods:

• A longitudinal reliability study involving adults with chronic neck pain (≥6 months).
• Two examiners with varying experience performed bilateral LC imaging using standardized SWE presets.
• Measurements of shear-wave speed and Young's modulus were obtained, with reliability assessed using intraclass correlation coefficients (ICCs).

Main Results:

• Good to excellent inter-examiner agreement was observed for single (ICC_3,2 > 0.818) and averaged (ICC_3,2 > 0.866) LC stiffness measurements.
• Intra-examiner repeatability was good to excellent (ICC_3,1 > 0.891) for a novice examiner and excellent (ICC_3,1 > 0.973) for an experienced examiner.
• No significant differences in stiffness were found based on sex or side of measurement (p > 0.05).

Conclusions:

• A standardized SWE workflow enables reproducible measurement of LC stiffness in individuals with mechanical neck pain.
• For longitudinal studies, maintaining a single operator is recommended.
• In multi-examiner settings, averaging at least two acquisitions per side enhances the sensitivity to detect true changes in LC stiffness.