Validity Of TIRADS In Diagnosing Malignant Thyroid Nodules With Histopathological Correlation

Abstract

Introduction: Thyroid nodules are a very common clinical presentation with the estimated prevalence of 3-7% by palpation and 19-
67% by high resolution ultrasonography (USG).
Aim:The aim of this study is to determine the risk of malignancy, accuracy in each Thyroid Imaging Reporting and Data System
(TIRADS) categories and determine the specific ultrasonographic features associated with malignancy by using histopathologic
diagnosis as the reference standard.
Material and Methods: This is a single-centre prospective observational study carried out on 60 patients with a suspected thyroid nodule
referred from department of Otorhinolaryngology, Surgery and Internal Medicine to the department of radiology and imaging over a
period of 6 months . All patients are subjected to ultrasound and the lesions were characterized according to TIRADS categories.
Patients in TIRADS 3,4 and 5 categories underwent Fine needle aspiration cytology (FNAC) as per the guidelines. Correlation of
TIRADS category with histopathologic diagnosis were assessed. The sensitivity, specificity, positive predictive value, negative
predictive value and accuracy of the screening test along with their 95% CI were calculated. The threshold for statistical performance
was set at 0.05. Each ultrasonographic features were also compared with its histopathologic results.
Results: The sensitivity, specificity, positive predictive value, negative predictive value and accuracy of TIRADS 4 and 5 categories in
relation to histopathologic diagnosis were 92.00%, 25%, 50%, 80%, and 55% respectively.
Among individual USG parameters, microcalcification was most sensitive (76%) and specific (81%) feature with an adjusted OR 14.44
(95% Cl 2.387 to 87.426, p=0.00173) followed by irregular margin and taller-than-wider shape with a specificity of 88% and 88%
respectively.
Conclusion:Due to the high incidence of thyroid nodule among general population ultrasound screening using TIRADS scoring is a
sensitive reliable predictor of thyroid malignancy. Risk of malignancy increases significantly with higher TIRADS score.
Microcalcification is the most frequent ultrasound feature that is predictive of thyroid malignancy.