CT flat scan refers to a type of CT scan, common such as CT flat scan and enhanced CT, while spiral CT is a type of CT, the earliest time people use the ordinary single-row CT, this CT scan time is long, the layer thickness is generally around 1cm, belongs to the thicker, smaller lesions are easy to miss, and the amount of radiation to the patient is relatively large. The spiral CT that has been developed now uses data acquisition, and the scanning speed is greatly accelerated, and the clarity of the image is also improved than before, the amount of radiation to the patient is reduced, and the examination time is also significantly shortened. Spiral CT can perform both CT plain and enhanced CT examinations, and subsequent image processing, such as three-dimensional reconstruction, can be performed after spiral CT is done.