Meaning of pni-rads classification? For lung nodules, we can classify them according to pni-rads, which can be divided into six categories: the first category, is undetected nodules. The second category is benign nodules. The third category is uncharacterized nodules. The fourth category is suspected malignant nodules, and the fourth category is subdivided into three levels of ABC: 4A is a relatively high risk of malignancy, 4B is directly a high likelihood of carcinoma in situ or minimally invasive carcinoma, and 4C that’s a high likelihood of malignancy. The fifth category is for nodules that are strongly suggestive of malignancy on screening CT, and the sixth category is for nodules that are histologically confirmed to be malignant. That is to say, the degree of malignancy is gradually increasing from the first to the sixth category, and the management of different degrees of malignancy is also different. For the first category, routine screening is sufficient; for the second category, if the nodule is determined to be benign, there can be no follow-up, but some of them need to be followed up, according to the schedule set by the doctor, to carry out regular follow-up; for the third category, the doctor sets up a different follow-up plan according to the size of the nodule; for the fourth category, according to the difference of ABC, the doctor sets up a different program of examination and follow-up; for the fifth category, routine In the fifth category, the diagnosis is further confirmed by further examination; in the sixth category, the diagnosis is confirmed and the next step of treatment is actively pursued.