Assessment of Normal Thyroid Volume by Ultrasonography among Children in Uyo, Akwa Ibom State, Nigeria

Abstract

The purpose of this study was to assess the normal thyroid volume among children in study population by ultrasonography and compare with values from previous works. The research was a prospective cross sectional study. A sample population of children between 2months to 17years was selected. They were volunteers drawn from daycare centres, nursery, primary and post primary schools in Uyo metropolis. Those that met the inclusion criteria were scanned at the school clinics where their height and weight were also obtained prior to the scan. Five hundred volunteers were scanned from September 2011 - November 2012. Kaimax 2200G portable ultrasound machine manufactured in 2011, a gray scale real-time scanner fitted with a 7.5 MHz transducer was used for the study. The study was conducted by one dedicated operator and the scan protocol was drawn and checked by a Sonographer and a Radiologist to establish the measurement technique and address the intra-observer variability. For each thyroid lobe, the volume was obtained by multiplying Length, Thickness and Width (L x T x W). The result was multiplied by a correction factor, 0.497. The Right and Left volumes were summed to obtain the total thyroid volume (Tvol). Data processing and statistical analyses were performed using Microsoft EXCEL 2010. The range and mean thyroid volume for the pre-school age groups were 0.11-3.2 cm3 and 1.22 ±1.61cm3 respectively while 0.84 – 8.22cm3 and 2.68 ± 2.53cm3 were the range and mean for the school-age subject respectively. Statistically, there is no sex difference in thyroid volume as well as between the right and left lobe. The study has derived a nomogram for thyroid dimensions from 0-17years of age. A statistically significant lower thyroid gland volume than the WHO/ICCIDD reference values (p>0.05) was noted in the study population. However there is significant similarity with data obtained in similar environment. Keywords: Comparison, children, thyroid volume and ultrasonography.