Patients with cerebral infarction are shown to have T1WI low signal and T2WI high signal lesion areas, which are usually visualized within two hours of patient onset. The diagnostic sensitivity of early cerebral infarction can reach 88%-100%, and the specificity can also reach 95%-100%. Cranial MRI includes cranial MRI scanning and angiography. Cranial MRI scanning is mainly used to examine the brainstem, cerebellum and small infarct foci; angiography is generally used to examine cerebral vessels, which can detect the stenosis and the degree of stenosis of intracranial vessels, and is mainly applicable to the examination of large vessel lesions. Functional cranial MRI can detect ischemic changes within minutes of onset and includes diffusion-weighted imaging and perfusion-weighted imaging. Diffusion-weighted imaging and perfusion-now-weighted imaging show the same area of lesion extent, generally referred to as the site of nonviable reversible injury, and the inconsistent area of the two examinations, usually referred to as the ischemic semidark zone, which is mainly protected by clinical treatment and provides a scientific basis for thrombolytic treatment of early cerebral infarction. For cranial MRI, there is generally no radiation to human body, but if there are metallic things in the patient’s body, such as dentures and metal stents, MRI is generally prohibited.