 Hello everyone. I am Dr. Shahita Bhanu, third year resident, Department of Radio Diagnosis from Sri Lakshmi Narayana Institute of Medical Sciences, Pondicherry. The title for my paper presentation today is Risk stratification of thyroid nodules using TIRAD system with its histopathological correlation, a cross-sectional study at a tertiary care center in Pondicherry. The American Thyroid Association defined thyroid nodules as discreet lesions within the thyroid gland radiologically distinct from the surrounding parankaima. Literature shows that the incidence of thyroid nodules is four times higher in women than men. Nodules in the thyroid are very common and their prevalence depends largely on the identification method. Privileged rate just by palpation is only 4-7% whereas by using ultrasound it is as high as 20-76% in an adult population. The nodules discovered in radiographic studies are called as thyroid incident alomas. The average prevalence of thyroid malignancy rates across the world in thyroid nodules ranges from 4 to 6.5%. TIRADs, that is thyroid imaging and data system proposed by Howard et al. is a classification system based on five ultrasound characteristics which will allow for a better selection of thyroid nodules which has to undergo FNAC and thereby avoid unnecessary invasive procedures. It also unifies the language between radiologists and endocrinologists worldwide by using standard lexicons. In this study, we studied the thyroid nodules using high-resolution ultrasound and correlated the TIRADs with the Bethesda system for reporting thyroid cytopathology. By comparing these data, efficacy of TIRADs in differentiating benign from malignant nodules are assessed. AIM was to evaluate the ultrasound characteristics of thyroid nodules and characterize their risk for malignancy using the ACR-Tirad system. To do FNAC of the thyroid nodule and categorize according to the Bethesda system for reporting thyroid cytopathology, the objective was to assess the accuracy of the ACR-Tirad system in differentiating benign from malignant ones by correlating with the Bethesda system which is a gold standard. Materials and methods, the study was conducted at the Department of Radiodiagnosis, Sri Lakshmi Narayana Institute of Medical Sciences for a period of 18 months from January 2020 to July 2021. With an aim to evaluate the ultrasound characteristics of thyroid nodules, the sample size was 50. It was a time-bound cross-sectional study. Inclusion criteria, patients referred for ultrasound thyroid and found to have a thyroid nodule on B-mode, patients with an ability to understand and sign the informed consent. The patients not giving consent, known case of thyroid malignancy and patients with bleeding disorders were excluded from the study. The examination was carried out with high-resolution B-mode ultrasound using Sonics SPQ color Doppler plus Siemens with high-frequency linear probe to image a thyroid and neck both in transverse and sagittal planes. The thyroid nodules were staged according to the TIRADS system. FNAC of the nodule was taken. Neck was also assessed for suspicious lymph nodes. The FNAC results were followed up for Bethesda staging. The accuracy of TIRADS compared with the Bethesda was finally assessed during sensitivity, specificity, positive predictive value and negative predictive value. Results, the nodules were studied on the basis of five ultrasound characteristics and were further differentiated into benign and malignant with FNAC and histopathology. Frequency of nodules under TIRADS 1, 2, 3, 4, 5 were 14, 20, 4, 6 and 6 respectively. The nodules were then subjected to FNAC. Five nodules, that is 10% of the nodules were inconclusive of FNAC. 37 nodules were benign and 8 nodules were malignant. Then the nodules were subjected to histopathological examination. On histopathology, 35 nodules were benign and 15 nodules were malignant out of which 11 were papillary, 2 were medullary and 2 were follicular carcinomas. The FNAC results were compared with histopathology findings. So out of the five nodules which were inconclusive on FNAC, 60% were benign and 40% were malignant and out of 37 nodules which were benign on FNAC, 83.8% were benign and 16.2 were malignant. One nodule which was malignant on the initial cytology was benign, was sent for histopathology. 87% nodules were malignant in both FNAC and histopathology. Then the histopathology nodules were compared with the TIRADS system. The TIRADS 1 nodules were 85% benign and 14% malignant. TIRADS 2 nodules were 85% benign, 15% malignant. And TIRADS 3 lesions were all 100% benign. TIRADS 4 lesions were 33% benign and 66% malignant whereas TIRAD 5 lesions were all malignant. These are my representative cases. This is a TIRADS 5 lesion, a nodule with a solid composition, hypoechoic nodule, irregular margins and punctate echogenic foci which gave a total point of 10 points and it was given TIRADS 5 and this is a TIRADS 4 lesion, a well-defined hypoechoic nodule compared to the surrounding thyroid parankaima with core scalifications and hence the score of 4 was given and I signed TIRADS 4. It turned out to be medullary carcinoma. Ultrasound is a non-invasive method, safe and easily reproducible method in characterization of the TIRADS nodules based on the 5 sonological features to assess the criteria for TIRADS. In a current study, totally 14 nodules were categorized under TIRADS 1 out of which 12 were benign and 2 were malignant. The positive predictive value for malignancy of TIRADS 1 lesions were 14.3% and 65.7% specific. The 20 nodules which were categorized into TIRADS 2, 17 were benign and 3 were malignant with a positive predictive value of 15%. Nodules categorized into TIRADS 3 were 100% benign with a positive predictive value for malignancy was 0%. The nodules under TIRADS 4 and 5 were 12 nodules with suspicious features. There were 6 nodules in TIRADS 4 in which 2 were benign and 4 were malignant and with a positive predictive value of 66.7%. The 6 nodules under TIRADS 5, all 6 nodules turned out to be malignant on histopathological correlation. So in our study to compile the features in favor of a benign nodule were ecogenicity more than that of the thyroid-parenchyma, absence of calcification and well-defined margins and that of malignancy were hyper-ecogenicity, irregular margins and taller than wider dimensions. To conclude, if the nodules are properly classified on ultrasound, the probability of a particular nodule being malignant can be inferred from the ultrasound-based TIRADS system only with a certain level of confidence. The positive predictive value of TIRADS in stratifying a risk for malignancy in a nodule for Category 1, 2, 3 and 4, 5 were 14.3, 15, 0, 66.7 and 100% respectively. So our study was based on the hypothesis that USG-based risk stratification of nodules is accurate and hence unnecessary invasive procedures like FNAC and biopsy can be avoided and thus pay away for better patient care. Still further studies with large sample size are required to prove this hypothesis which can reduce patient's cost, avoid unnecessary invasion and prevent complications. These are my references. Thank you.