Abstract
Purpose
The aim of this study was to determine whether the ratio of the thyroid width (Th) to the trachea width (Tr) is a useful technique for sonographic estimation of thyroid size in neonates and small children.
Methods
We prospectively performed sonographic examination of the thyroid gland in 30 pediatric subjects ranging in age from 1 week to 12 years. The sum of the maximum width of the left thyroid lobe and the maximum width of the right lobe was considered the Th. Each subject's thyroid was classified as small, normal sized, or large on the basis of the Th value in reference to the subject's body height. The ratios of the Th to the Tr were then calculated and compared among the 3 groups by 1βway analysis of variance. Correlation and regression analyses were performed to determine the correlation between body height and Tr. A p value of less than 0.05 was considered significant.
Results
The mean Th/Tr ratios (Β± standard deviations) for the 3 groups were as follows: small, 1.25 Β± 0.19; normal sized, 2.09 Β± 0.19; and large, 4.10 Β± 2.42. The difference in the Th/Tr ratios between the 3 groups was statistically significant (p < 0.0001). A significant positive correlation was found between Tr and body height (p < 0.001; r = 0.85).
Conclusions
The Th/Tr ratio is a simple, practical parameter for estimating the size of the thyroid gland in neonates and small children. Β© 2004 Wiley Periodicals, Inc. J Clin Ultrasound 32:82β85, 2004