Comparision between the three-dimensional ultrasound VOCAL technique and two-dimensional ultrasonic in measurement of thyroid volume

Abstract

Objective To evaluate and compare the consistency and repeatability of three-dimensional ultrasound (3D-US) virtual organ computer-aided analysis (VOCAL) technique and two-dimensional ultrasound (2D-US) in the measurement of thyroid volume. Methods The thyroid volume of 50 healthy female adults aged 18 to 68 years were measured by 2D-US and 3D-US. The 2D-US was used to measure the three diameter lines (L, H, W) of the largest thyroid section, and the thyroid volume was calculated by the classical ellipsoid formula V=0.523×L×H×W. The 3D-US VOCAL technique was used to acquire the thyroid three-dimensional data, and VOCAL software was used to measure the thyroid volume. The two methods of measurement were also compared and analyzed. Results The coefficient of variation in the intra-assay was 0.738% and 1.59% respectively for the 3D-US VOCAL technology and traditional 2D-US measurement of thyroid volume, and the 95% limit of agreement in the intra-assay was (-0.26 cm3, 0.22 cm3) and (-0.32 cm3, 0.46 cm3) . In addition, the correlation coefficient in the inter-assay were 0.970xx and 0.942xx, and the 95% limit of agreement were (-0.36 cm3, 0.37 cm3) and (-0.75 cm3, 0.64 cm3) . To compare the two methods of measuring thyroid volume, the 3D-US VOCAL had a lower variation coefficient in the intra-assay, a higher correlation coefficient in the inter-assay and a narrower 95% limit of agreement, which showed that the repeatability of the 3D-US VOCAL technique measuring was better than the traditional 2D-US in measuring thyroid volume. Conclusions The 3D-US VOCAL technique shows a higher repeatability in measuring thyroid than traditional 2D-US. As a safe, simple and feasible precise measurement method, it provides a reliable and effective new method for clinical measurement of irregular organ volume. Key words: Thyroid; Volume; Three-dimensional ultrasound; Virtual organ computer-aided analysis technique