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

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.