Acute ischemic stroke has ischemic penumbra and actual infarct core, and when there is a bigger difference in the volume of the two, it is called " mismatch". It is not only manifested as a mismatch between the clinical manifestations and the infarct core, but also as a mismatch between the infarct core and the perfusion area. The advancement of neuroimaging technology enables this " mismatch" phenomenon to be manifested through different imaging methods or different sequences of the same imaging method, thereby providing more guidance for the further diagnosis and treatment process.