Association between sonographic features of thyroid nodules and cellular examination obtained by fine needle aspiration

As we know, thyroid nodules are common, but many of them are benign, and this shows that sampling of nodules is not necessary to diagnose benignity.The aim of this article was to determine the diagnostic accuracy of ultrasound features for diagnosing malignant thyroid nodules in patients referred to Fajr infirmary in Ilam.

This descriptive-cross-sectional study was conducted on 122 patients referred to Fajr Ilam Clinic in October 2015 to January 2018.Clinical characteristics such as age, gender, BMI and history of underlying thyroid diseases and Hashimoto's thyroiditis were collected with the help of a questionnaire.The dependence of ultrasound characteristics with thyroid malignancy was determined using a multivariate analysis test. This ultrasound feature was compared with the results of fine needle aspiration cytology and the diagnostic accuracy indices were calculated for each ultrasound feature.This article was conducted using statistical tests, chi-square, independent t-test, Mann-Whitney test, and bivariate logistic regression using Spss software.

The study sample included of 30(24.6%) malignant and 92(75.4%) benign nodules. Hypoechogenicity and microcalcification showed statistically significant positive associations with thyroid malignancy (P<0.05).Also, according to Fisher's exact test, 7% and 20% of men had benign and malignant nodules, and 86% and 80% of women had benign and malignant nodules, respectively. But there was no statistically significant difference between the two groups (P>0.05). Hypoechogenicity had 63.3% sensitivity and 67.04% specificity, microcalcification had 60% sensitivity and 65.93% specificity. Having at least one good sonographic feature resulted in the highest sensitivity (86.67%), while the presence of both features had almost perfect specificity (91.3%) and the highest positive likelihood ratio (4.21).

According to the results of this article, the presence of Microcalcification variables and Hypoechogenicity are the most important criteria in predicting thyroid malignancy, and they are Locate in the TI-RADS grading. Therefore, nodules larger than 1 cm in size with the characteristics of microcalcification and homogeneity ultrasound should be the main focus of diagnostic evaluations.