Abstract: Objective To investigate the value of MRI for measuring thyroid volume. Method Thyroids of 51 normal adults were scanned by MRI using T1WI-and T2WI-weighted imaging technology. Volumes were compared for the left and right thyroid lobes and for the two genders. Results Mean total thyroid volume was（14.297±5.44） cm³；mean volume was similar for the right lobe （7.395±2.858） cm³ and left lobe （6.902±2.656） cm³；P>0.05）. Total thyroid volume was significantly greater in men（n=26）than in women（n=25，P<0.05）. Comparing the left lobe with right lobe between men and women，the volume of bilateral lobe volume in men was significantly larger than those in women. The difference was statistically significant（P<0.05）. Conclusion MRI may allow noninvasive measurement of thyroid volume，and the results suggest the need to take into account gender differences in thyroid volume when making treatment decisions.

Key words: Thyroid, Thyroid volume, Magnetic resonance imaging technology