Background: Vietnam reported 5471 new thyroid cancer patients which rank tenth in 2020. The sensitivity of computed tomography (CT) is higher than ultrasound in evaluation of invasive thyroid cancer and the lymph nodes metastasis. Materials and methods: One hundred and four patients (72 women, 32 men; age range 16 – 80 years; mean 44 years) with 116 malignant tumors of the thyroid were enrolled in this descriptive study. All patients were performed a neck contrast-enhanced CT and the results were compared with the surgical and histopathologic findings. Results: The features of thyroid cancer on CT include irregular margins, unclear boundaries, calcification and strong contrast enhancement after injection. The sensitivity (Se), specificity (Sp), positive predictive value (PPV) and negative predictive value (NPV) of CT were as follows: 99%, 84.6%, 98.1% and 91.7% for capsular invasion; 98.7%, 97.4%, 98.7% and 97.4% for invasion of strap muscles; 85.7%, 97.2%, 66.7% and 99% for invasion of subcutaneous soft tissues; 77.3%, 98.9%, 94.4% and 94.9% for tracheal invasion; 76.5%, 98.9%, 92.9% and 96.1% for esophageal invasion; 83.3%, 100%, 100% and 99% for invasion of blood vessels. The rate of lymph node metastasis in thyroid cancer was high and the central cervical lymph node group predominates. Conclusion: CT can be a valuable tool for evaluation of invasive thyroid cancer and the lymph nodes metastasis.
Keywords: Thyroid cancer, computed tomography, invasion, lymph nodes metastasis