The presence of blood flow signals in the thyroid gland is detected by color ultrasound Doppler, and blood flow signals in the thyroid gland are often found in patients with thyroid nodules. If the thyroid nodule is hard and the border is not clear, and if the nodule has some calcification and blood flow signal and the aspect ratio of the nodule is greater than 1, this may indicate that the thyroid nodule is malignant and surgery is the treatment of choice. If the nodules are in good condition, without the above mentioned conditions, they should be benign nodules and should be reviewed regularly.