Thyroid nodule malignancy risk stratification, known as the TI-RADS (Thyroid Imaging Reporting and Data System) classification, is an assessment of the risk of benign and malignant nodules based on imaging such as ultrasound, and can generally be categorized into grades 1 to 6. Grade 1 is no nodule, with a 0% malignancy rate. Grade 2 is a benign nodule with a 0% malignancy rate. Grade 3 is a potentially benign nodule with a malignancy rate of <2%. Grade 4 is categorized into 4A, 4B, and 4C, where 4A is lowly suggestive of malignancy with a malignancy rate of 2% to 10%, 4B is moderately suggestive of malignancy with a malignancy rate of 10% to 50%, and 4C is highly suggestive of malignancy with a malignancy rate of 50% to 90%. Grade 5 is highly suggestive of malignant nodules with a malignancy rate of >90%. Grade 6 is biopsy-proven malignant nodules. If an abnormality occurs, fine needle aspiration of the thyroid is recommended to clarify the benign or malignant nature of the diseased tissue. If you find thyroid nodules, it is recommended that you seek timely medical attention, make a clear diagnosis under the guidance of your doctor, treat it aggressively, and review it regularly.