Agreement between Sonographic Features and Fine Needle Aspiration Cytology in the Diagnosis of Thyroid Nodules in a Tertiary Hospital

Abstract

Objective. Management of thyroid nodules relies on the Thyroid Imaging Recording and Data System (TIRADS) for sonographic findings and the Bethesda System for Reporting Thyroid Cytopathology (TBSRTC). The proponents aimed to determine the concordance between sonographic TIRADS findings and cytological diagnosis by TBSRTC in the evaluation of malignancy of patients with thyroid nodules.

Methodology. Sonographic and cytology results collected from 2018 to 2022 were obtained to determine whether there is an agreement between TIRADS and TBSRTC findings.

Results. Two hundred sixty-two (262) samples were obtained. Overall accuracy of predicting TIRADS category was highest for echogenic foci. Thyroid nodule distribution was highest for TIRADS 3 and 4 sonographically and TBSRTC II cytologically. There is low agreement between TBSRTC and TIRADS in the categorization of nodules as benign, implying that nodules may show sonographic features suspicious of malignancy despite being categorized as TBSRTC I or II by cytology. However, nodules categorized as TBSRTC III to VI show sonographic features suspicious for malignancy at the very least.

Conclusion. The correctness of TIRADS prediction is highest for echogenic foci although not significantly higher than other parameters. The overall predicting power of TIRADS for the absence of malignancy is high for TIRADS 1 and 2, whereas TIRADS 5 predicts a 31.11% risk of malignancy making it a strong indication for FNAC. However, prediction of malignancy in TIRADS 3 and 4 nodules must be in association with other factors since a significant percentage may turn out to be TBSRTC II.