Thyroid gland sonography was performed on 380 healthy medical school students. Twenty-eight subjects were excluded because they revealed either nodules (in 25 subjects, % 6.5) or heterogeneous echo patterns (in three subjects) in their thyroid glands by examination. Finally 352 individuals ( 204 females, 148 males) were included in the statistical evaluation. The ages of the subjects were between 18-24 years with a mean age of 20.5 years. The mean right lobe volume of all population was found to be higher than mean left lobe volume (6.95±2.6 mt vs 5.72±2.2 ml, p<0.001). The population had a mean thyroid volume of 12.1±3.5 ml mean (SD, range 4.9-24.3ml). A statistical significant difference was found between mean thyroid volume of males (13.7±3.4ml; n=148) and females (11.1±3.2ml; n=224, p<0.001). Also there was a significant difference between body weights, heights and body surface areas of males and females (73±10 kg vs 57±8kg; 177±6cm vs 164±6cm; 1.89±0.15m2 vs 1.62±0.12 m2 respectively, p<0.001). A positive correlation was found between height (p<0.001), body weight (p<0.001) and body surface area (p<0.001) and thyroid volume in the total population. There was also a positive correlation between height (p<0.05), body weight (p=0.002) and body surface (p=0.00l) and thyroid volume in females. But no correlation could be found between any of these parameters and thyroid volume in the male sex. The 97th percentiles of thyroid volume for each sex was calculated and found to be 22.4 ml in males and 20.2 mi in women. In conclusion, with the results of the present study we suggest that values greater than 20.2 ml for women and 22.4 ml for men should be considered as goiter in adults.
Keywords: Thyroid Diseases, Thyroid Volume, Ultrasonography