To propose a risk stratification system for intermediate-risk
thyroid nodules (
TNs) according to American Association of Clinical Endocrinologists, American College of Endocrinology and Associazione Medici Endocrinologi Medical (AACE/ACE/
AME) Guideline with ultrasound (US) features. 1000 patients with 1000 nodules (902 benign nodules and 98 malignant nodules) were included. All the nodules were confirmed with either fine needle aspiration (FNA) cytology and follow-up or histology results after surgery. Univariate analysis and binary multivariate logic regression analysis were applied to analyze the possible risk US features associated with
malignancy. Receiver operating characteristic curves (ROC) were drew and compared. Univariate analysis and binary multivariate logistic regression analysis showed that indeterminate hyper-echoic spot (OR = 4.544), slightly ill-defined margin (OR = 2.559), slight hyper-echogenicity (OR = 1.992) and no macro-calcification (OR = 1.921) were risk factors for the intermediate-risk
thyroid nodules (
TNs). A predicting model was established based on the 4 risk factors. The risk rates of
malignancy were 5.7% (26/455) in Stage I, 11.0% (49/445) in Stage II, 23.1% (21/91) in Stage III, 33.3% (3/9) in Stage IV. In conclusion, for the intermediate-risk
TNs, special attention should be paid to the
TNs with indeterminate hyper-echoic spot, slightly ill-defined margin, slight hyper-echogenicity, or no macro-calcification. The probability of
malignancy increased with the number of risk factors increasing.