Accuracy of American College of Radiology Thyroid Imaging Reporting and Data System in Characterisation of Thyroid Nodules: A Tertiary Hospital Study in India

Abstract

Background: Thyroid nodules (TNs) are commonly and frequently encountered in the day-to-day clinical practice. Clinical suspicion of malignancy as well as patient anxiety is the frequent reasons for fine-needle aspiration cytology or biopsy (FNAC/B) of TN. American College of Radiology has developed a Thyroid Imaging Reporting and Data System (ACR TI-RADS) based on TN ultrasound features to suggest malignancy to minimise the number of TN subjected to FNAC/B. Aim to assess the diagnostic accuracy of ACR TI-RADS in our Tertiary Hospital Health Facility. Patients, Materials and Methods: Sixty-nine patients with TN included in our study following institutional ethics committee approval and written informed consent underwent high-resolution ultrasonography followed by FNAC using a high-frequency linear transducer on Siemen Acuson S3000 ultrasound scanner. The data were recorded in the predesigned proforma followed by statistical analysis to assess the diagnostic accuracy of ACR TI-RADS. Results: Our study had female predominance (50/69) with the left side more commonly affected (37/69). The mean age of the participants was 42.2 ± 15.6 years with significantly higher age at presentation in those with malignant TN. Mixed nodules were predominant (46/69) with nearly half of the malignant nodules being solid and only 8/61 benign nodules being solid. Although the majority of the nodules were hyperechoic (50/69 including 2 malignant), a significant number of the hypoechoic/very hypoechoic nodules (6/14) were malignant with only 8/61 benign nodules being hypoechoic. Half of the malignant nodules (4/8) had lobulated or ill-defined margins, whereas only 2/61 benign nodules had similar margins. The majority (5/8) of the malignant TN had internal punctate echogenic foci with only 1/61 benign TN showing similar appearance. Half of the malignant TN (4/8) had lymphadenopathy, whereas it was noted in only 2/61 cases of benign TN. Conclusions: TNs though have a high prevalence, but malignant TNs are uncommon with majority being solid, taller than wider, hypoechoic with microcalcifications. The presence of adenopathy is usually a feature of malignant thyroid nodule rarely seen with benign nodules. Thus, to summarise all TNs should be thoroughly evaluated as per ACR TI-RADS for stratification of risk of malignancy.