Predictive US findings for differentiating between malignant and benign thyroid nodules: Doppler and microvascular imaging according to the TI-RADS and pathologic subtypes of malignancy.

purposeThis study investigated whether Doppler and microvascular imaging help distinguish malignant from benign thyroid nodules in relation to the Thyroid Imaging Reporting and Data System (TI-RADS) and the pathologic subtype of thyroid malignancy.

methodsThis study included 113 consecutive thyroid nodules from 103 patients with confirmed final diagnoses from February 2022 to September 2022. Two radiologists conducted a retrospective review of ultrasonographic (US) findings and assigned vascular scores by consensus using color Doppler imaging (CDI) and microflow imaging (MFI) on a 4‑point visual scale. Vascular scores were compared between malignant and benign nodules and analyzed by US pattern according to the Korean TI‑RADS (K‑TIRADS).

resultsOf the 113 nodules, 72 were benign and 41 were malignant. All nodules were categorized using the K‑TIRADS lexicon, and each lexicon feature (composition, echogenicity, orientation, margin, and calcification) significantly differentiated malignant from benign lesions (P≤0.008). The CDI score also differed significantly (P<0.001). In subgroup analysis by K‑TIRADS pattern, differences in CDI and MFI scores were not observed for low‑ and intermediate‑suspicion nodules, whereas in high‑suspicion nodules benign lesions had higher CDI and MFI scores than malignant ones (P=0.018 and P=0.051, respectively). Classic papillary thyroid carcinoma showed lower vascular scores on both CDI and MFI, while the follicular variant showed higher scores (P=0.075 and P=0.007, respectively).

conclusionCDI and MFI may assist in distinguishing between malignant and benign nodules, and evaluation of nodular vascularity may be tailored to the TI‑RADS category.