The Flair sequence is an image of the MRI sequence, the base image of the MRI is T1 item and T2 item, the Flair image is an extended sequence, in order to better observe the lesion, some people also call it the pressurized water image. The T1 sequence is mainly to observe the anatomical structure. Flair sequence is the compression of water out of the cerebrospinal fluid, and it is easy to see the high signal lesion against the low signal black background.