Diagnostic Performance of Elastography Compared With Cytopathology in the Evaluation of Thyroid Nodules Suspicious for Malignancy

Introduction: Cytopathologic evaluation is the gold standard for the diagnosis of thyroid cancer. Ultrasound elastography is a noninvasive technique that assesses tissue stiffness and may help select patients for biopsy based on the stiffness of thyroid nodules. Methods: A cross-sectional observational study was conducted in patients with thyroid nodules suspicious of malignancy who underwent qualitative and semiquantitative elastography. These results were compared with the cytopathologic findings of each lesion following fine-needle aspiration biopsy. Bethesda categories V and VI were considered malignant. Bethesda III and IV nodules, corresponding to indeterminate and follicular categories, were not included in the analysis as malignant nodules. Results: A total of 106 thyroid nodules were evaluated, predominantly in females, with a mean age of 54 years. Most nodules were benign (83.1%). Concordance between qualitative elastography and malignancy was practically null, with a Kappa value of -0.0503 (95% CI: -0.10 to -0.004). The median semiquantitative value was similar across all Bethesda categories: 1.14 (0.79-2) in benign nodules (Bethesda II), 1.59 (0.69-4.12) in Bethesda V nodules, and 1.68 (0.36-3.92) in Bethesda VI nodules. Elastography did not allow clear discrimination between benign and malignant nodules using a precise numerical threshold. A cutoff value of 1.48 is proposed, as it yielded the best balance between sensitivity (64.29%, 95% CI: 38.76-86.66) and specificity (63.77%, 95% CI: 51.98-74.1). Conclusion: Elastography demonstrated limited utility in differentiating benign from malignant nodules in this study. Further research is needed to define its clinical role in the implementation of noninvasive approaches for the early detection of thyroid cancer.