The Determination of Thyroid Dimension by Routine Neck Computed Tomography and Its Relationship to Age, Sex, and Body Size in Korean Adults

Lee, Dong Hee; Cho, Kwang Jae; Jun, Beom Cho; Hwang, Sung Jae; Kim, Dong Kee; Kim, Min Sik; Cho, Seung Ho

Abstract

BACKGROUND AND OBJECTIVES
The purpose of this study was to establish a "normal" range of dimensions of the thyroid glands on routine neck computed tomography in the Korean population. Also, this study investigated the possible influence of some physical factors. MATERIALS AND METHOD: Neck computed tomography scans of 100 adults were reviewed retrospectively to measure the size of the thyroid gland and to evaluate its relationship to the trachea and cervical vertebra. The width, thickness, and length of each thyroid lobes, as well as the estimated volume of the thyroid gland were measured. The cross-sectional areas of the trachea and cervical vertebra were utilized as two parameters of standard in measuring the size of thyroid glands according to different body size. RESULTS: The mean widths were 15.7 mm (right) and 15.2 mm (left). The mean thicknesses were 20.9 mm (right) and 18.9 mm (left). The mean lengths were 61.8 mm (right) and 58.5 mm (left). The mean estimated volumes of each lobe were 8.8 cm3 (right) and 7.6 cm3 (left). The mean volume of total thyroid glands (including isthmus) was 17.5 cm3. There was no significant difference between the total study group and normal thyroid function group. The dimensions of right lobe was significantly larger that of the left. There was no significant difference between males and females. The results of the multiple regression analysis supported the likelihood that the influence of the body weight was most pronounced. CONCLUSION: Our study presents initial data for assessing the thyroid gland on neck computed tomography scans in Koreans, providing the limit values of normal thyroid glands.