The main methods of detecting thyroid nodules include: palpation, ultrasound, CT, and MRI. Palpation Palpation of the neck during physical examination is the primary and easiest method of detecting thyroid nodules. However, palpation can only detect large or superficial nodules, and the experience of the examiner can have an impact on the detection rate of nodules. If the nodule is deep, or if the nodule is small and does not differ significantly in texture from the gland, then palpation alone is likely to miss the nodule. Therefore, this method has some limitations. Ultrasound has the ideal resolution to detect tiny nodules as small as 2mm in diameter, improving the sensitivity of thyroid nodule detection. Therefore, it can be used both as a basis for diagnosis of nodules and for follow-up of nodule growth. CT/MRI CT and MRI are not superior to ultrasound in the diagnosis of thyroid nodules. Therefore, they should only be considered when the nodule is located behind the sternum and cannot be detected by transcervical ultrasound, or when the relationship between the nodule and the surrounding tissue needs to be understood. Because the thyroid gland contains iodine and has a natural contrast advantage with surrounding tissues, clear images can usually be obtained with CT plain scan; because iodine-containing contrast agents may affect thyroid function, enhanced scans should be avoided in patients with nodules with combined abnormal thyroid function and used only when necessary.