Defining Normative Sonographic Measurements of Neonatal Thyroid Volumes: Results of 165 Healthy Neonates from a Single Center in Northwest Malaysia

BACKGROUND: Congenital hypothyroidism is the most common cause of treatable mental impairment and growth retardation in newborns. Early diagnosis requires measurement of serum thyroid-stimulating hormone (TSH) and free T4 coupled with an ultrasound of the thyroid gland. However, detailed sonographic evaluation of the thyroid gland requires comparison to the local thyroid normative volumetric values, which is currently lacking. METHODS: A cross-sectional study was conducted from November 10, 2015, to April 18, 2018, recruiting 165 healthy neonates with normal TSH in their 1(st) week of life, from a single center in Northwest Malaysia. Ultrasound thyroid was done by a single ultrasonographer (κ = 0.86, percent agreement = 92.4), and the thyroid volume (TV) was calculated using the Brunn formula. RESULTS: All measurements showed skewed distribution with no significant difference between the right and left lobes. The local normative values for neonatal total TV was 0.61 (interquartile range [IQR] = 0.230) cm(3), 0.31 (IQR = 0.150) cm(3) for right TV, and 0.28 (IQR = 0.110) cm(3) for left TV. There was a strong correlation between the right and left TVs, r = 0.767, P < 0.001. There were also no differences in the total TV across different genders and races. CONCLUSION: The normative values for TV determined in our study may be used accordingly in clinical practice to evaluate thyroid hypoplasia or goiter by other Asian countries due to the similarly shared biodemography.