The Usefulness of High Resolution Ultrasonography in the Differentiation of Thyroid Nodule / 대한내분비학회지

ABSTRACT

BACKGROUND: Fine needle aspiration(FNA) is regarded as the best procedure in the diagnosis of thyroid malignancies. However, the rate of false negative and indeterminate results are between 5~10 and 10~30%, respectively. Therefore, a new diagnostic tool to assist FNA is required. Recently, high resolution ultrasonography(US) has become a useful tool in the detection of malignant thyroid nodules. Therefore, the sonographic characteristics differentiating malignant from benign nodules were analyzed, and the usefulness of US in the diagnosis of thyroid malignancy assessed. METHODS: Of the 212 patients that underwent surgery due to a thyroid nodule, at the Daegu Catholic University Hospital between January 2002 and June 2004, and 181 patients(199 nodules) who underwent high resolution US examination before surgery, were included in this study. The characteristics of the sonographic parameters, such as depth/width ratio, shape, margin, structure, sponge sign, calcification and halo, and the homogeneity and echogenicity of the solid component and invasion, were observed. RESULTS: In a univariate analysis of the nonfollicular neoplasms, the depth/width ratio, shape, margin, structure, calcification and halo, and the homogeneity and echogenicity of the solid component were found to be significant parameters. The "sponge sign", a new parameter suggested by us, was found only in benign nodules. In a multiple logistic regression analysis, only the depth/width ratio, shape, presence of calcification and echogenicity of the solid component were significant parameters. According to the results of the multiple logistic regression analysis, the point and estimate of each characteristic of the significant parameters were found, and a formula for calculating a score for the prediction of malignancy computed. At a score of 0.44, the sensitivity and specificity of US were 85.9 and 88.7%, respectively. In a univariate analysis of follicular neop-lasms, the shape, calcification and echogenicity were found to be significant parameters. CONCLUSION: It was conclude that high resolution US is a very useful tool in the differentiation of benign and malignant nodules, especially in nonfollicular neoplasms. It is also suggested that the "sponge sign" might be used as a strong indicator for the confirmation of benign nodules