Reliability of side-to-side sonographic cross-sectional area measurements of upper extremity nerves in healthy volunteers.

OBJECTIVES

In sonographic evaluations of peripheral nerves, the healthy, contralateral side may be used as an internal control for the pathologic one. Therefore, the inherent side-to-side differences must be minimal. The goal of this study was to determine the reliability of side-to-side measurements of upper extremity nerves in healthy volunteers.

METHODS

Forty participants with no upper extremity abnormalities were included. Upper limb nerves were evaluated bilaterally at the usual pathologic sites by 3 musculo-skeletal radiologists in separate sessions. To assess intraobserver and interobserver agreement, sonographic examinations were repeated 2 months after the first evaluations. The median nerve, ulnar nerve, musculocutaneous nerve, and radial nerve were considered. Nonparametric tests were used for statistical analysis.

RESULTS

Minimum detectable differences with relative 95% confidence intervals were reported. Intraobserver and interobserver agreements were good (0.73 < κ < 0.85). When the combined influence of the observer and the repeated measurement was evaluated, the reliability was 80% to 87%.

CONCLUSIONS

In general, the healthy contralateral side can be used as an internal control considering that changes in minimum detectable differences are related to the anatomic site considered.