Correlation between Ultrasound TI-RADS and Bethesda FNAC Scoring in Thyroid Lesions: A Retrospective Analysis

Abstract

ABSTRACT Objectives: Primary objective of the study was to determine the association between the TI-RADS system of thyroid lesion evaluation on ultrasound and the cytological findings of thyroid lesions by FNAC (graded as per the Bethesda system). The secondary objective was to study the outcome of high TI-RADS and high Bethesda grades in terms of malignant potential determined by histopathological examination. Materials and Methods: A multi-centric retrospective hospital-based study was done for all patients who underwent sonography for evaluation of thyroid lesions and subsequently fine needle aspiration cytology (FNAC) from 2018 to 2021 at two hospitals in two different states of India. Clinical and radiological data were obtained from hospital records. The data hence obtained was subjected to statistical analysis. The outcome of high-grade TIRADS and Bethesda scores in terms of malignant potential (confirmed by histopathology) was also evaluated. Results: A total of 249 patients fulfilled the inclusion criteria. 129 patients (51.8%) were in 36-55 year age group with female predominance. The majority of cases in the study belonged to TI-RADS 3 category (33.73%) on sonography and Bethesda Grade III (28.91%) after cytological analysis. Out of 72 Bethesda grade III cases, 59 (81.9%) had TI-RADS 3 score. Similarly, out of 67 Bethesda Grade IV cases, 55 (82%) had TI-RADS 4 scores showing maximum concordance. The accuracy of TIRADS 4 and 5 lesions and Bethesda grade 4-6 lesions in detecting malignancy confirmed on HPE was 67.9 and 73.6%. Discussion: Our study done on 249 patients from varying demographic profiles showed that the correlation between sonography and cytological findings of thyroid lesions was statistically significant. Both diagnostic modalities helped to correctly determine the severity of the lesions, and malignant potential and enabled grading into clinically relevant groups that decided the further management as per laid down guidelines. Conclusion: The concurrent use of ACR-TIRADS on sonography coupled with the Bethesda system of cytological evaluation for thyroid nodules is clinically appropriate in ascertaining the RoM (Risk of malignancy) in a thyroid nodule.