The degree of blood supply to the nodule is reflected in the thyroid nodule stellate blood flow signal, and the nature of the thyroid nodule can be roughly determined based on the degree of blood supply. There are four grades of blood supply in thyroid nodules. Grade zero is no blood flow signal; grade one is 1-2 punctate blood flow signals; grade two is 3-4 punctate blood flow signals, or a signal of a very clear vessel with a duct wall; grade three is more than 4 blood flow signals, or a signal of two vessels with a complete duct wall. Usually zero or primary blood flow signal, benign nodules are more likely; secondary and tertiary blood flow signal, malignant nodules are more likely, which is only one of the indicators to determine the nature of nodules. In addition to the blood flow signal, thyroid nodules can also be judged by their size, growth rate and growth pattern. For example, if the nodule used to grow horizontally but is growing longitudinally, if the texture of the nodule becomes hard, if the border is not clear, if there are gravel-like calcifications, if there are adhesions to the surrounding soft tissues, and if there are multiple punctate calcifications in the surrounding lymph nodes, the nodule is considered to have a higher rate of malignancy.