A Multicenter Prospective Validation Study for the Korean Thyroid Imaging Reporting and Data System in Patients with Thyroid Nodules

• Published in: Korean journal of radiology 2016, 17(5), , pp.811-821
• Main Authors: Ha, Eun Ju, Moon, Won-Jin, Na, Dong Gyu, Lee, Young Hen, Choi, Nami, Kim, Soo Jin, Kim, Jae Kyun
• Format: Article
• Language: English
• Subjects: Adult; Biopsy; Biopsy, Fine-Needle - methods; Calcification; Cysts; Diagnosis, Differential; Female; Humans; Male; Management decisions; Middle Aged; Multivariate analysis; Patients; Predictive Value of Tests; Prospective Studies; Research Design; Retrospective Studies; Risk Assessment - methods; Sensitivity and Specificity; Thyroid; Thyroid gland; Thyroid Neoplasms - diagnostic imaging; Thyroid Neoplasms - pathology; Thyroid Nodule - diagnostic imaging; Thyroid Nodule - pathology; Ultrasonic imaging; Ultrasonography - methods; Validation studies; 방사선과학
• ISSN: 1229-6929; 2005-8330
• DOI: 10.3348/kjr.2016.17.5.811

To validate a new risk stratification system for thyroid nodules, the Korean Thyroid Imaging Reporting and Data System (K-TIRADS), using a prospective design. From June 2013 to May 2015, 902 thyroid nodules were enrolled from four institutions. The type and predictive value of ultrasonography (US) predictors were analyzed according to the combination of the solidity and echogenicity of nodules; in addition, we determined malignancy risk and diagnostic performance for each category of K-TIRADS, and compared the efficacy of fine-needle aspiration (FNA) with a three-tier risk categorization system published in 2011. The malignancy risk was significantly higher in solid hypoechoic nodules, as compared to partially cystic or isohyperechoic nodules (each p < 0.001). The presence of any suspicious US features had a significantly higher malignancy risk (73.4%) in solid hypoechoic nodules than in partially cystic or isohyperechoic nodules (4.3-38.5%; p < 0.001). The calculated malignancy risk in K-TIRADS categories 5, 4, 3, and 2 nodules were 73.4, 19.0, 3.5, and 0.0%, respectively; and the sensitivity, specificity, positive predictive value, negative predictive value, and accuracy for malignancy were 95.5, 58.6, 44.5, 96.9, and 69.5%, respectively, in K-TIRADS categories 4 and 5. The efficacy of FNA for detecting malignancy based on K-TIRADS was increased from 18.6% (101/544) to 22.5% (101/449), as compared with the three-tier risk categorization system (p < 0.001). The proposed new risk stratification system based on solidity and echogenicity was useful for risk stratification of thyroid nodules and the decision for FNA. The malignancy risk of K-TIRADS was in agreement with the findings of a previous retrospective study.