Preoperative Staging of Differentiated Thyroid Carcinomas: Comparison of USG and CT with Intraoperative Findings and Histopathology

To study the efficacy of USG and CECT in preoperative staging of differentiated thyroid carcinomas in comparison to the intraoperative and histopathological findings. A prospective, observational study was conducted in a tertiary care hospital over a period of one and a half years where USG and CECT of 23 subjects with histopathologically proven differentiated thyroid malignancy were analysed to study the characteristics of the primary tumour, lymphatic metastasis and evaluate the sensitivity and specificity of the radiological investigations in comparison to the intra-operative and histopathological findings. When compared with intraoperative and histopathological T-staging, USG had an accuracy of 69.5% and 73.9% and CECT had an accuracy of 78.2% and 73.9% respectively. The sensitivity and specificity of USG and CECT in determining a malignant nodule was 71.4% and 33.3% and 52.4% and 66.7% respectively. The N-staging according to the histopathological examination findings was in agreement with that of USG in 65.2% and CECT in 65.2% patients. The sensitivity and specificity of USG was 94.4% and 41.7% and that of CECT was 92.2% and 44.4% respectively in detecting lymphatic metastasis. The sensitivity and specificity of USG was 94.4% and 44.4% and that of CECT was 92.2% and 27.3% respectively in detecting lateral compartment lymphatic metastasis. USG identifies the characteristics of the malignant nodules better and CECT has a higher identifying central compartment lymphatic metastasis. CECT should be used as an adjunct to ultrasound to determine the extent of lymphatic metastasis and staging of disease.