Comparison of three volumetric techniques for estimating thyroid gland volume

Aim: The aims of this study were to estimate the preoperative thyroid volume in patients with a multinodular goiter by the use of ultrasonography (USG) and magnetic resonance imaging (MRI), and then to compare these approaches with the postsurgical total volume measured by Archimedes’ principle. Materials and methods: In this study, we compared 3 methods for the determination of thyroid volume: thyroid volume measured with ellipsoid formula via 2-dimensional ultrasonography (2D USG); the stereological (point-counting) method using MRI; and the postsurgical total volume determined by the fluid displacement technique as a gold standard. Results: Thyroid volumes were calculated in a total of 20 patients (15 women and 5 men) who underwent total thyroidectomy. The mean ± SD thyroid volumes of the fluid displacement, point-counting, and ellipsoid methods were 82.75 ± 48.87, 80.45 ± 48.96, and 75.50 ± 46.59 cm3, respectively. No significant difference was found among the methods of calculating thyroid volume (P 0.05). The mean coefficient of error for the thyroid gland estimates derived from the technique of point-counting with MRI was under 4%. The 2D USG volume is a 10.62% underestimation of the thyroid gland volume compared with the actual volume. Conclusion: It can be concluded that there was no statistically significant difference between the 2 methods, but the 2D USG volume was underestimated; therefore, we think that the stereological method is a more efficient and reliable method than USG for thyroid gland volume estimation.