The presence of blood flow in the thyroid gland is not a characteristic sign of cancer, as thyroid adenoma or thyroiditis can be accompanied by increased blood flow. For such patients, MRI can be performed, and even pathological puncture can be performed if there is doubt, to determine the presence of tumor. An increase in blood flow cannot fully diagnose thyroid cancer or malignancy. The presence of blood flow signal in thyroid tumor is usually shown by ultrasound, while whether the thyroid gland is cancerous or not should be judged not only by blood flow, but also by signal strength, concomitant conditions, and whether the boundary is clear.