To investigate the preoperative ultrasound (US) quality control status of thyroid follicular tumors of uncertain malignant potential (FT-UMP), and to compare differences in quality control indicators before and after the implementation of the thyroid imaging reporting and data systems (TI-RADS) guidelines.

A retrospective analysis was conducted on patients who underwent surgical resection at the First Affiliated Hospital of Soochow University between January 2017 and December 2025. All included patients had a pathological diagnosis of FT-UMP and had undergone preoperative thyroid US examination. US reports and images were systematically reviewed to assess three core quality control indicators: the completeness rate of US report descriptions, the image storage completeness rate, and the utilization rate of TI-RADS classification. These indicators were compared between the periods before and after the implementation of TI-RADS guidelines using the chi-square test or Fisher's exact test. Static US images of FT-UMP nodules were independently interpreted by two radiologists with over 7 years of diagnostic experience in thyroid US. According to the Chinese TI-RADS (C-TIRADS) and the American College of Radiology TI-RADS (ACR TI-RADS) criteria, US features (composition, shape, margin, echogenicity, and echogenic foci) and malignancy risk stratification (TI-RADS categories) were recorded. Differences in US feature description and malignancy risk assessment between the two classification systems for FT-UMP were compared.

A total of 219 FT-UMP nodules from 217 patients were included, comprising 69 males and 148 females, with a mean age of 45.78 years and a mean maximum nodule diameter of 41.07 mm. Following the standardized implementation of the C-TIRADS guidelines, the completeness rate of US report descriptions increased from 21.26% to 95.65%, the image storage completeness rate improved from 50.39% to 93.48%, and the TI-RADS classification utilization rate increased from 0% to 97.83% (χ²=117.862, 45.683, and 209.954, respectively; all P＜0.001). In routine clinical US diagnosis, FT-UMP was most commonly diagnosed as thyroid adenoma (46.33%) or nodular goiter (27.68%), and most nodules were assigned to C-TIRADS category 3 (42.22%) or category 4A (47.78%). Discrepancies were observed between C-TIRADS and ACR TI-RADS in nodule composition description and malignancy risk assessment of FT-UMP. Based on C-TIRADS criteria, 66.67% of FT-UMP nodules exhibited solid composition; the proportions of nodules classified as C-TIRADS categories 3, 4A, and 4B were 28.77%, 59.36%, and 11.87%, respectively. According to ACR TI-RADS criteria, 82.65% of FT-UMP nodules presented as solid or almost entirely solid; the proportions of nodules assigned to ACR TI-RADS categories 2, 3, 4, and 5 were 12.79%, 34.25%, 42.92%, and 10.04%, respectively.

Standardized application of the C-TIRADS guidelines can effectively improve the completeness rate of US report descriptions, the image storage completeness rate, and the TI-RADS classification utilization rate for FT-UMP. FT-UMP is frequently diagnosed as thyroid adenoma or nodular goiter on preoperative US. Additionally, discrepancies in risk stratification exist between C-TIRADS and ACR TI-RADS for FT-UMP.