Characterization of thyroid nodules using the proposed thyroid imaging reporting and data system (TI-RADS).

Abstract

The Thyroid Imaging Reporting and Data System (TI-RADS) was proposed based on a scheme similar to Breast Imaging Reporting and Data System (BI-RADS) lexicon used in breast lesions. The purpose of this study was to evaluate its interobserver variability and accuracy. We included 498 nodules in 437 patients undergoing thyroidectomy. Two endocrine surgeons and 2 endocrinologists independently reviewed sonographic images. There was moderate to substantial interobserver agreement for final assessment category (kappa = 0.61). The overall sensitivity, specificity, and negative predictive value (NPV) were 94%, 43%, and 96%, respectively. Positive predictive values (PPVs) for categories 4 and 5 were 32% and 60%. The sensitivity was 92%, 99%, 96%, and 89%, whereas the specificity was 25%, 37%, 41%, and 62% for tumor sizes of <2, 2 to 3, 3 to 4, and >4 cm, respectively. TI-RADS is a helpful but not optimal reporting tool in characterizing thyroid lesions. Tumor size has a considerable impact on interobserver concordance and diagnostic performance.