Reevaluation of the Correlations between Ultrasound Features of Thyroid Nodules and Grades of Bethesda Classification

Abstract

AIM: To reevaluate the correlations between ultrasound (US) features of thyroid nodules (THNs) and grades of Bethesda classification, to select correctly the patients who must undergo fine needle aspiration (FNAB). MATERIAL AND METHODS: In this study, we have included 260 cytologies of thyroid gland between the period of 2014–2018. The procedures are performed at radiology department of Hygeia Hospital. In our study are excluded the cases with a high risk of hemorrhage and the patients which did not accept the anesthetic procedure because of anxiety. The study includes only the first punctions with their respective Bethesda classification and not repeated FNAB cases. First using the z test, we compared the percentage occupied by the Bethesda categories that are indicative of surgery (BIV + BV + BVI) at US features that suspect malignancy (hypoechogenicity, microcalcifications, abnormal contours, central vascularization), with the percentage occupied by group (BIV + BV + BVI) at the US features which indicate benignity (hyperechoic, no microcalcifications, peripheral vascularization, cystic-solidocystic, spongiform, normal contours). Furthermore, We have evaluated utilizing the odds ratio if there was a correlation between TR4 and TR5 categories in ACR/TIRADS classification and the categories (BIV+BV+BVI) for any statistical significance. The significance of the dimensions of the nodule was tested as an indicator for surgical intervention. For this purpose, the percentage occupied by the nodules with a diameter larger than 1.5 cm at (BIV + BV + BVI) group was compared with the percentage occupied by nodules smaller than 1.5 cm at BIV + BV + BVI. In addition, we observed if there was a strong statistical connection between nodules larger than 1.5 cm and the Bethesda categories that suggested malignancy. There was no statistical test made for the features “taller than wide” and microcalcifications because of the small number of cases. It was also made a comparison of percentages (BIV + BV + BVI) even for three clinical features: Men versus women, solitary nodule versus multinodular goiter, left lobe versus right lobe. We compared the percentages occupied by the (BIV + BV + BVI) group of categories in patients over 45 years old with the percentages occupied by this group at patients younger than 45 years old. We also noted which of Bethesda categories is more frequent. CONCLUSIONS: The features that are more indicative for FNAB are hypoechogenicity, consistency, intranodal vascularization, and extralobar positioning. If a THN has one of the above features and has a dimension of more than 10 mm, it has an indication for FNAB. Indications for FNAB increase with the increasing of the abovementioned features of a THN. The combination of US features that suggest malignancy, TR4 and TR5, with BIII category is a strong indicator for surgical intervention. The results of this study are similar with the results of prior studies, and we could not distinguish any specific US feature that has an absolute indication for FNAB. The appropriate determination of the US features of a THN in correlation with the patient’s clinic information will determine the proper indication for a FNAB.