The Diagnostic Accuracy of American College of Radiology Thyroid Imaging, Reporting and Data System (ACR TI-RADS) Ultrasound Classification for Diagnosing Thyroid Carcinoma in Thai Population

Abstract

Background: Thyroid carcinoma is the most common endocrine tumor. Both ultrasonography and Fine needle aspiration should be performed for accurate diagnosis and evaluation. The American College of Radiology Thyroid Imaging Reporting and Data System (ACR TI-RADS) is a risk stratification system for thyroid lesions, based on sonographic characteristics. Objective: The aim of this study was to determine the predictive value of ACR TI-RADS in prognostication of malignancy across the Thai population. Method: We conducted a retrospective, study in Queen Savang Vadhana Red Cross Memorial Hospital, Thailand between January 2020 and September 2021. Data from 125 patients with 201 thyroid nodules who underwent ultrasonography using TIRADS classification, FNA biopsy and histopathology report were collected. The sonographic features were described according to ACR TI-RADS. These results were analyzed for sensitivity, specificity, and predictive values using SPSS. Results: ACR TI-RADS had specificity of 73.6% and sensitivity of 70.5%. Positive predictive value and negative predictive value of 58.2% and 82.7%, respectively. The accuracy of the ACR TI-RADS in our study was 71.6%. The prevalence of malignancy in TR1, TR2, TR3, TR4, and TR5 was 0%, 0%, 22%, 42%, and 92%, respectively. The echogenic foci has the highest area under the curve for detecting thyroid malignancy. Bethesda score 3 delivered as the cutoff for identifying malignant nodules in the TR4 and TR5 groups with sensitivity 86.7, and specificity 85.7. Conclusion: The ACR TI-RADS provides effective malignancy risk stratification for thyroid nodules. Thyroid nodules classified as TR4 or TR5 in our study are highly suspicious for malignancy and should be considered as indication for FNA.