PURPOSE

To compare the value of Thyroid Imaging Reporting and Data Systems proposed by Kwak (KWAK-TIRADS) and ACR (ACR TI-RADS) and 2015 American Thyroid Association (ATA) guidelines in the diagnosis of surgically resected thyroid nodules.

METHODS

From January 2015 to December 2015, 2544 thyroid nodules in 1758 patients who underwent thyroidectomy at our center were included. The KWAK-TIRADS category, ACR TI-RADS and ultrasound (US) pattern based on ATA guidelines were assigned to each thyroid nodule. Nodules were divided into groups according to their maximal diameter further.

RESULTS

Of all the nodules, 863 (33.9%) were benign, whereas 1681 (66.1%) were malignant. The malignancy percentage of ACR TI-RADS category 1, 2, 3, 4, and 5 were 0%, 1.3%, 9.1%, 52.5%, and 88.8%, respectively. KWAK-TIRADS and ATA guidelines showed a better diagnostic efficiency than ACR TI-RADS (P < 0.01). ACR TI-RADS demonstrated a higher specificity (79.7%, P < 0.05), whereas the ATA US pattern had a higher sensitivity (95.5%, P < 0.01). The TIRADS (KWAK-TIRADS and ACR TI-RADS) category and ATA guidelines performed better in differentiating nodules >1 cm. KWAK-TIRADS showed better diagnostic efficiency than the other methods in differentiating nodules >1 cm (AUC: 0.92, P < 0.01).

CONCLUSIONS

KWAK-TIRADS and ATA guidelines provide a better diagnostic efficiency than ACR TI-RADS. The TIRADS (KWAK-TIRADS and ACR TI-RADS) category and ATA guidelines perform better in differentiating nodules >1 cm than nodules ≤1 cm. KWAK-TIRADS perform better in differentiating nodules >1 cm than other methods.