Purpose: The present study was conducted in a study group of thyroid nodules with a definite histopathological diagnosis acquired using a one-to-one matching process to assess the efficacy of malignancy stratification algorithms of the American College of Radiology (ACR) and European Thyroid Association (ETA) in the delineation of thyroid nodules having unequivocal diagnosis by means of histopathological examination.
Methods: A hundred and sixty-five patients having 251 thyroid nodules with histopathologically proven definitive diagnoses were included in this study during a 5-year period. All patients had preoperatively undergone ultrasonography (US) examination, and US characteristics of the thyroid nodules were retrospectively analyzed and assigned in compliance with the TIRADS categories recommended by the ACR and ETA. The diagnostic efficacy in the delineation of thyroid nodules and unnecessary fine-needle aspiration (FNAB) rates were evaluated.
Results: A hundred and eighty-nine (75.30%) nodules were diagnosed as benign, while 62 (24.70%) nodules were reported to be malignant based on histopathological assessment. The sensitivity was found to be 71% and 73%, while the specificity was calculated as 75% and 80% for the ACR- and EU-TIRADS, respectively. The area under the curve value of the ACR-TIRADS was 0.78, in comparison to 0.80 with the EU-TIRADS. The unnecessary FNAB rates were 61% for the ACR-TIRADS and 64% for the EU-TIRADS as per the recommended criteria of each algorithm.
Conclusions: The diagnostic performance of both malignancy stratification systems was signified to be moderate and sufficient in a cohort of nodules with definite histopathological diagnosis. In light of our results, we demonstrated the strengths and weaknesses of the ACR- and EU-TIRADS for physicians who should be familiar with them for optimal management of thyroid nodules.