Diagnostic Accuracy of Thyroid Nodules using the TIRADS and Bethesda Criteria – Is there a Correlation?

  • Background: Thyroid nodules are a prevalent finding and while most are benign, some may possess malignant features. The Thyroid Imaging Reporting and Data System (TIRADS) is a simple system predicting malignancy, used by radiologists. We compared the TIRADS system of classifying thyroid nodules on ultrasound with the findings on fine-needle aspiration cytology (FNAC) using the Bethesda System.

    Methods: A retrospective analysis was conducted of all patients who underwent ultrasound-guided FNA of thyroid nodules in our institution, since its establishment in May 2018 to December 2018. The TIRADS score was assigned by several radiologists and the results were compared to the Bethesda results of the FNA.

    Results: Overall, 70 patients with a total of 85 thyroid nodules, underwent FNAC. The average age was 57 years (16-84) with a M:F ratio of 1:6. Five patients (7%) had family history of thyroid malignancy and 7(10%) – history of radiation exposure. The average nodule diameter was 2.4 cm (0.8-6.1cm). Fourty nodules (47%) were classified as TIRADS 2; 20 (23%) as TIRADS 4 and 9 nodules (10%) as TIRADS 5. Most nodules (97%) classified as TIRADS 2 and 1 were benign with FNAC results of Bethesda 2. However, most (85%) of TIRADS 4 nodules were also benign per FNAC (Bethesda 2). Fourty-four percent of TIRADS 5 nodules were indeed malignant per FNA (Bethesda 5-6).

    Conclusions: While the TIRADS classification correlates with the Bethesda criteria for benign thyroid nodules, it may require some modifications with regards to suspicious nodules. Larger-scale studies are required.  


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