Sonographic diagnosis of thyroid nodules: Correlation with the results of sonographically guided fine‐needle aspiration biopsy

Purpose. To assess the reliability of sonography in differentiating benign from malignant thyroid nodules and selecting lesions for fine‐needle aspiration (FNA). Methods. During a 2‐year period, the following 7 sonographic parameters were assessed in 129 patients with thyroid nodules: size, number, echogenicity, echotexure, margin regularity, presence of calcifications, and presence of a hypoechoic rim. Sonographically guided FNA was performed on thyroid nodules ≥5 mm in diameter. Out of 184 FNAs, we obtained 168 specimens adequate for cytologic analysis and 16 (9%) nondiagnostic specimens. Results. FNA diagnoses included 150 (89%) benign and 18 (11%) malignant nodules. Among 53 solitary nodules, 11 were carcinomas and 42 were benign ( p < 0.01). The mean size of the carcinomas was 28 ± 12 mm versus 18 ± 10 mm for benign nodules ( p < 0.01). The following sonographic features were significantly associated with malignancy: hypoechogenicity, irregular margins, calcifications, and absence of a hypoechoic rim. Differences in echotexure between malignant and benign nodules were not statistically significant. Conclusion. Sonographically guided FNA should be performed on thyroid nodules ≥5 mm in diameter with sonographic characteristics that suggest malignancy. © 2006 Wiley Periodicals, Inc. J Clin Ultrasound 35, 2007