Differentiation of Benign and Malignant Thyroid Nodules: Sonographic Analysis and a New Scoring System

ABSTRACT

PURPOSE: To analyze the synthetically created sonographic features of thyroid nodules, we present here a new scoring system for the sonographic features that are suggestive of malignant thyroid nodules. We also evaluated the accuracy and clinical significance of this system. MATERIALS AND METHODS: In this study, we included 725 thyroid nodules of 405 patients that were pathologically proven by USG-guided percutaneous fine-needle aspiration biopsy (FNAB) or surgery. Two radiologists analyzed the sonographic features according to the internal content, margin, echogenecity, shape and calcification. We scored from 0 point to 2 point for each feature, and then we calculated the total scores and classified them as three groups according to the total score such as low risk (0-3), intermediate risk (4-6) or high risk (7-10). We demonstrated the difference of the frequency and the positive predictive value among the three groups by using the Chi-square test (p<0.005). RESULTS: For 725 nodules, 654 (90.2%) were benign and 71 (9.8%) were malignant. For 589 nodules classified as low risk, 10 (1.7%) were malignant. For 102 nodules classified as intermediate risk, 32 (31.4%) were malignant. For 34 nodules classified as high risk, 29 (85.8%) were malignant. There was a statistically significant difference in the frequency and positive predictive value of malignancy among the three groups (p<0.001). CONCLUSION: There was a statistically significant difference in the frequency and positive predictive value of malignancy among the three groups for the new scoring system presented in this study to analyze the synthetically sonographic features of thyroid nodules. So, we think that sonography can be helpful for making the differentiation between benign and malignant nodules. When we find thyroid nodules on sonography, we can reduce the unnecessary FNAB and we can diagnose malignant nodules at an earlier stage.