The feasibility of reducing the thresholds for biopsy in ACR TIRADS and AI TIRADS

Abstract At present, there is still controversy over whether to perform fine needle aspiration (FNA) on sub-centimeter thyroid nodules with high suspicion of malignancy. Our aim was to estimate the feasibility of reducing the original thresholds for biopsy in American College of Radiology Thyroid Imaging Reporting and Data System (ACR TIRADS) and Artificial Intelligence TIRADS (AI TIRADS). A total of 3201 thyroid nodules with definitive histology obtained were included. Ultrasound categories were assigned according to each TIRADS. We lowered the original FNA thresholds of TR3-TR5 in ACR and AI TIRADS and estimated whether the decreased FNA thresholds could be accepted and used to modified ACR and AI TIRADS. Then, we estimated and compared the diagnostic performance between modified TIRADS and original TRADS to determine if the decreased thresholds could be an effective strategy. 1474 (46.0%) thyroid nodules were diagnosed as malignant after thyroidectomy. Modified ACR TIRADS had higher sensitivity and lower specificity, unnecessary biopsy rate, missed malignancy rate compared with original ACR TIRADS (all P< 0.05). Similar trends were seen in modified AI TIRADS versus original AI TIRADS (all P < 0.05). In conclusion, biopsy of all nodules with TR5 in both ACR TIRADS and AI TIRADS might be an effective strategy, regardless of the nodules dimension. This paper contributes to the contradictory concerning whether perform FNA for the nodules smaller than 10 mm.