Utility of ultrasound elastography in evaluation of thyroid nodules and correlation with cytology

Abstract

Background: Ultrasound elastography (USE) has emerged as a potentially useful tool in the evaluation of thyroid nodules. The aim of this study was to assess the efficacy of elastography in differentiating benign from malignant thyroid nodules with fine-needle aspiration cytology (FNAC) analysis as reference standard. Materials and Methods: This was a cross-sectional prospective study carried out at a tertiary care center in South India between May 2014 and March 2015. Consecutive patients with solid nodule in the thyroid gland on conventional ultrasound (US) underwent USE, followed by US-guided FNAC of the thyroid nodule. The findings of B-mode images and USE were correlated with cytology. Statistical analysis was performed using SPSS version 24. Descriptive statistics were presented as mean ± standard deviation. The diagnostic sensitivity, specificity, positive predictive value, and negative predictive value of USE were calculated. Results: A total of sixty patients with sixty solid thyroid nodules were enrolled in the study. The mean age of the patients was 48.27 ± 16.10 years. About 83.3% were females. The frequency of benign nodules on cytopathologic analysis was 60% (n = 36). Seventy-five percent of the malignant lesions had irregular or poorly defined borders with lobulated margins on US. The sensitivity, specificity, positive predictive value, and negative predictive value of USE were 91.7%, 77.77%, 73.33%, and 93.3%, respectively, with FNAC as reference standard. Higher elastography scores were found to be significantly associated with malignant cytology (P = 0.0001). Conclusion: Elastography, with its fairly high diagnostic accuracy and correlation with malignant cytology, can be an effective noninvasive adjunctive tool in distinguishing benign from malignant thyroid nodules.