Evaluation of the Reliability of US-based TI-RADS in Predicting Thyroid Malignancy

Abstract

Thyroid nodules are a common and prevalent problem encountered in every day clinical practice. Ultrasound (US) is considered to be the initial imaging modality used in the evaluation of thyroid nodules. The TI-RADS (Thyroid Image Reporting and Data system) is an US-based system used to categorize thyroid nodules and stratify their malignant risk in the aim to standardize reporting and simplify communication among practitioners. The aim of this study is to compare the TI-RADS classification of thyroid nodules on ultrasound with the findings of fine-needle aspiration cytology (FNAC) reported using the Bethesda system. A retrospective study of 59 thyroid nodules that underwent single radiologist bedside neck and thyroid US over a period of one year between January 2020 – January 2021 was performed. The US findings were based on the TI-RADS and all the nodules were eventually subjected to US-guided FNAC. Clinico-pathological retrospective analysis was performed by comparing TI-RADS findings to the Bethesda FNAC classification. Comparing TI-RADS results with the Bethesda system of classification, the risk of malignancy for TI-RADS 2, TI-RADS 3, TI-RADS 4, and TI-RADS 5 were 0%, 10%, 50%, and 100%, respectively. A significant association was noted between the TI-RADS and Bethesda system of classification (P < 0.001). We derived 91.3% sensitivity, 88.9% specificity, 84% positive predictive value, and 94.1% negative predictive value for our study. There is a strong correlation between thyroid sonographic reporting using the TI-RADS and Bethesda cytological classification system for thyroid nodules. The TI-RADS classification is an effective method for risk stratification of thyroid nodules into categories predictive of their malignant potential. This aims to guide further management and facilitate the selection process for fine-needle aspiration biopsy, thus avoiding unnecessary procedures.