The number of rows of CT refers to the number of detectors in the CT machine. 128-row CT belongs to spiral CT, which is a very advanced examination method at present. Compared with 16-row CT, 32-row CT and 64-row CT, the scan layer thickness is thinner up to 0.3 mm, the scan time is shorter, the radiation dose to the patient is lower, and the image processing function is more powerful, such as doing energy spectrum CT, but due to the high cost of the machine, the examination cost will be higher. Some patients will confuse the number of CT rows and layers, the number of rows and layers are different, the number of layers represents the number of images that can be obtained by scanning a circle, to 64-row CT for example, 64-row CT has 64 layers or 128 layers, many hospitals are 128 layers of 64-row CT, not 128 rows.