Sensitivity and specificity of thyroid ultrasound for follicular thyroid carcinoma

Introduction: With the advancement of ultrasound examination technology in cases of thyroid nodule malignancy, several criteria and characteristic guidelines were developed, such as TIRADS (Thyroid Imaging, Reporting and Data System) criteria. These criteria assist clinicians in determining the diagnosis earlier than histopathological examination. The accuracy and sensitivity have been widely studied, but not much has been discussed regarding each characteristic item. This study aims to find the sensitivity, specificity, and accuracy of thyroid ultrasound examination against follicular-type thyroid carcinoma. Method: This research is a retrospective cohort using medical record data of patients at Dr. Soetomo General Hospital Surabaya during the 5-year research period (2017-2021). The conclusion of USG results and characteristics of USG malignancy compared with histopathological results. The summary of USG results consists of TIRADS score, TIRADS score combined with nodule vascularization, TIRADS score combined with lymph node enlargement, and TIRADS score combined with lymph node location. USG characteristics consist of a solid nodule, microcalcification, irregular margin, nodule taller than wider, hypoechoic nodule, vascularization, enlargement of lymph node and location of lymph node. Result: The conclusion of USG results based on TIRADS, TIRADS combined with nodule vascularization, solid nodule characteristics, and lymph node enlargement characteristics have a strong relationship with malignant histopathology results (p-value <0.05), with the highest sensitivity in the conclusion of USG results, which is the TIRADS score combined with nodule vascularization (90.9%), the best specificity is almost the same in all scores, the best positive predictive value (PPV) (74.1%), negative predicted value (NPV) (80.0%) and accuracy (75,7%) is the TIRADS score combined with nodule vascularization. The characteristics of thyroid nodules are the characteristics that have the best sensitivity, namely 68.2%, specificity 68.7%, PPV 75%, NPV 58.8%, and accuracy level 67.5%. Conclusion: Ultrasonography (USG) results, solid nodule characteristics, enlarged lymph node characteristics and TIRADS score above 3 (3.5) can be used as predictors of malignancy in thyroid nodule cases earlier than histopathology results.