Comparative Analysis of Methods for Obtaining Median Nerve Cross-Sectional Area Using Ultrasound.

Area of Science:

• Musculoskeletal imaging
• Diagnostic ultrasound
• Neurology

Background:

• Ultrasound measurement of median nerve cross-sectional area (CSA) is crucial for diagnosing carpal tunnel syndrome (CTS).
• Three common methods (A-B, Ellipse, Trace) are frequently used for CSA measurement.
• Evaluating the reliability and accuracy of these methods is essential for clinical practice.

Purpose of the Study:

• To compare the reliability and accuracy of three common ultrasound measurement methods (A-B, Ellipse, Trace) for median nerve CSA.
• To assess the impact of zoom-enhanced views on measurement reliability and accuracy.
• To identify the optimal method for consistent CSA measurements in suspected CTS.

Main Methods:

• Two observers measured median nerve CSA in 10 patients with suspected CTS using A-B, Ellipse, and Trace methods.
• Measurements were performed in standard and zoom-enhanced views.
• Comparison was made against ImageJ software analysis, with reliability assessed via ICCs and Bland-Altman analysis.

Main Results:

• All methods demonstrated high reliability (ICC: 0.940-0.994) but underestimated CSA compared to ImageJ.
• The Trace method showed the smallest mean difference from ImageJ (-1.26 mm²), indicating higher accuracy.
• Zoom-enhanced views improved interrater reliability but reduced overall measurement accuracy.

Conclusions:

• All three ultrasound methods are reliable for median nerve CSA measurement in CTS diagnosis.
• The Trace method offers modest advantages in accuracy and precision over A-B and Ellipse methods.
• The non-zoom Trace method is recommended for consistent longitudinal measurements, emphasizing the importance of user proficiency.