Incremental Value of Doppler Vascularity Beyond ACR TI ‐ RADS in Thyroid Nodule Biopsy Decision‐Making: A 13‐Year Retrospective Cohort Study

ABSTRACT Introduction The American College of Radiology (ACR) Thyroid Imaging Reporting and Data System (TI‐RADS) does not include Doppler vascularity. We evaluated whether increased vascularity identifies clinically significant cytology among nodules that do not meet ACR TI‐RADS fine needle aspiration (FNA) size thresholds. Methods A retrospective cohort study conducted at a tertiary referral imaging service included 3383 thyroid nodules in 2932 patients undergoing ultrasound‐guided FNA (January 2012–December 2025). Nodules were stratified into (1) ACR‐indicated (met ACR TI‐RADS size criteria); (2) vascularity‐only (marked vascularity, ACR not indicated, excluding PET‐avid and nuclear medicine cold nodules); and (3) other non‐ACR indications. Outcomes were Bethesda category. Outcomes were categorised according to the Bethesda System for Reporting Thyroid Cytopathology. Bethesda IV–VI and Bethesda V–VI outcomes were analysed separately. Exact binomial 95% confidence intervals were calculated; exploratory between‐group comparisons were performed descriptively. Results Among ACR‐indicated FNAs ( n = 1036), Bethesda IV–VI occurred in 87 (8.4%, 95% CI 6.8–10.3) and Bethesda V–VI in 33 (3.2%, 95% CI 2.2–4.4). In the vascularity‐only cohort ( n = 82), Bethesda IV–VI occurred in 8 (9.8%, 95% CI 4.3–18.3) with 0 Bethesda V–VI (0%, 95% CI 0–4.4). Other non‐ACR indications ( n = 974) yielded Bethesda IV–VI in 50 (5.1%, 95% CI 3.8–6.7) and Bethesda V–VI in 11 (1.1%, 95% CI 0.6–2.0). Conclusion In nodules that did not meet ACR TI‐RADS FNA thresholds, increased vascularity led to additional FNAs with no malignant cytology (Bethesda V–VI) and a modest proportion of Bethesda IV results. These findings support adherence to ACR TI‐RADS FNA thresholds without routine incorporation of vascularity alone.