Shear wave elastography for thyroid nodule evaluation in patients with chronic autoimmune thyroiditis.

Purpose: Shear wave elastography (SWE) is a valuable tool in discerning the malignancy risk of thyroid nodules. This study investigates whether 2D-SWE can reliably differentiate malignant thyroid nodules in patients with chronic autoimmune thyroiditis (CAT), despite the challenges posed by fibrosis, which can increase tissue stiffness and complicate diagnosis.

Methods: This retrospective observational study evaluated 130 thyroid nodules (91 benign, 39 malignant) in patients with underlying CAT using conventional ultrasound (B-mode) and 2D-SWE with SuperSonic Mach30 equipment (Supersonic Imagine, Aix-en-Provence, France). Pathology reports served as the reference standard.

Results: Out of the 130 nodules, 30% were malignant, and 70% were benign. 2D-SWE proved to be an excellent distinguisher between benign and malignant nodules. Malignant nodules had significantly higher elasticity indices compared to benign nodules (mean elasticity index: 47.2 kPa vs. 18.1 kPa, p < 0.0001; maximum elasticity index: 75 kPa vs. 26.2 kPa, p < 0.0001). The mean elasticity index was the most reliable elastographic parameter (AUC 0.907, sensitivity 87.2% [95% CI: 77.3-94.0%], specificity 84.6% [95% CI: 75.4-91.5%], and NPV 93.9% for a cut-off value of 30.5 kPa).

Conclusion: Our results confirm that 2D-SWE can accurately diagnose malignant thyroid nodules in cases with CAT (p < 0.0001), supporting its use as a complementary tool to conventional ultrasound.