Interobserver and intraobserver variations in sonographic measurement of thyroid volume in children

Objective: To determine the interobserver and intraobserver variations in sonographic measurement of thyroid volume in children. Design: Thyroid volumes of 30 healthy children were measured by three separate observers. Additionally each observer measured thyroid volumes of ten separate children three times. Methods: The data were used to assess intraobserver and interobserver variations in measurement of thyroid volume. Interobserver and intraobserver variations in measuring each diameter of the thyroid gland were also determined. The effect of thyroid size on interobserver and intraobserver variations was analyzed. Results: Intraobserver variation in measurement of thyroid volume was 8.4 ± 6.7% (mean ± S.D.). Interobserver variation was 13.3 ± 8.2%. The widest interobserver variation was encountered in determining the craniocaudal diameter of the thyroid gland. No correlation was found between thyroid volume and interobserver variation (r = -0.12, P = 0.27), whereas a slight but statistically significant correlation was found between thyroid volume and intraobserver variation (r = -0.26, P = 0.012). Conclusion: Significant interobserver and intraobserver variation occurs in sonographic measurement of thyroid volume in children.