Akçicek, MehmetDağ, NurullahKeskin, LezanPetik, BülentÜnlü, Serkan2026-06-192026-06-1920261844-4172https://doi.org/10.11152/mu-4533https://hdl.handle.net/20.500.12899/4888Aims: This study aimed to investigate changes in the stiffness of thyroid nodules following fine needle aspiration biopsy (FNAB), using shear wave elastography (SWE), a non-invasive imaging technique utilized in thyroid nodule evaluation. Material and Methods: A total of 82 patients scheduled to undergo FNAB for the first time were included. Ultrasound and SWE examinations were performed before the procedure and again 8 to 10 weeks after FNAB. Nodule stiffness was measured in kilopascals (kPa) during both evaluations, and changes in elasticity were assessed. Results: The mean SWE stiffness of the nodules significantly decreased from 21.80 ±11.43 kPa before FNAB to 17.83 ±9.98 kPa after FNAB (p = 0.001). Smoking status and serum free T3 levels were significantly associated with changes in SWE stiffness (p < 0.05). However, no significant difference was observed between TIRADS 3 and TIRADS 4 categories regarding the change in stiffness (p = 0.223). Conclusion: This study demonstrates a significant reduction in thyroid nodule stiffness after FNAB as measured by SWE. These post-biopsy changes may lead to potential misinterpretations in subsequent elastographic evaluations, possibly affecting diagnostic accuracy and clinical decision-making. © 2026, Societatea Romana de Ultrasonografie in Medicina si Biologie, All rights reserved.eninfo:eu-repo/semantics/openAccessElastographyFine Needle BiopsyThyroid NoduleUltrasoundArticle10.11152/mu-45332812732407890152-s2.0-105033286259Q2