OC12 - Stiffness matters: elastography enhances detection of thyroid cancer across histologic subtypes

Abstract Background/Introduction Grey-scale ultrasound (US) is the mainstay of thyroid-nodule assessment, yet its morphological criteria incompletely differentiate malignancy, especially across papillary (PTC), follicular (FTC) and medullary (MTC) thyroid carcinomas. Elastography, by objectively measuring tissue stiffness, may close this histology-specific diagnostic gap. Purpose To evaluate the added diagnostic value of elastographic stiffness in distinguishing malignant thyroid nodules, including PTC, FTC, and MTC, from benign lesions. Methods A pooled analysis of 211 surgically verified nodules examined prospectively at a single centre was performed. Ninety-four PTC-suspected nodules underwent SE and 2D-SWE with Hitachi Preirus and SuperSonic Mach30 systems; 97 Bethesda IV nodules, a cytologic category associated with an elevated risk of follicular-pattern malignancies, were assessed with the same protocol; and 20 pathology-confirmed MTCs were evaluated with Mach30 2D-SWE alone. Conventional US malignancy markers (hypoechogenicity, inhomogeneity, taller-than-wide shape, irregular margins, microcalcifications, capsular breach, suspicious lymphadenopathy) were recorded. Stiffness cut-offs deemed suspicious were a strain ratio 3.9 or a mean elasticity index 30.5 kPa. Pathology served as the reference standard. Diagnostic accuracy was analysed with receiver-operating-characteristic (ROC) curves and multivariable logistic regression. Results Eighty-one of 211 nodules (38.4 %) were malignant: 29 PTC, 32 FTC and 20 MTC. SE achieved sensitivity 81.5 % and specificity 93.8 %; 2D-SWE yielded 79.0 % and 94.9 %, respectively. Adding elastography to B-mode US increased the area under the ROC curve from 0.78 (95 % CI 0.71–0.84) to 0.92 (0.87–0.95) with SE and 0.91 (0.86–0.95) with 2D-SWE (p 0.001 for both). Elastographic stiffness remained an independent malignancy predictor in PTC (odds ratio OR 8.7), FTC (OR 6.3) and MTC (OR 5.9). Among benign Bethesda IV lesions, elastography correctly downgraded 14 of 65 nodules, projecting a 22% reduction in unnecessary surgery. Conclusion(s) Across three distinct thyroid-carcinoma phenotypes, SE and 2D-SWE provide robust, reproducible stiffness metrics that significantly enhance conventional US, narrow diagnostic uncertainty and support personalised surgical decision-making. Routine integration of elastography into thyroid risk-stratification algorithms may decrease indeterminate cytology rates and optimise patient outcomes.