CT shows normal and MRI shows ischemic foci, which may be relatively small or early ischemic acuity. In general, the size of the lesion is likely to affect the accuracy of the CT examination. If the lesion is relatively small in extent, it may not show up clearly when the CT examination is performed, resulting in a missed diagnosis. MRI, on the other hand, is more detailed and can accurately detect ischemic foci in the brain, and small foci will also show up clearly. Another common situation in which CT shows normal and MRI shows ischemic foci is that in the early stage of the onset of some diseases, for example, in the acute stage of cerebral infarction, if the area is not particularly large, CT is generally unable to see the early low-density foci, which can only be shown by MRI. It is recommended that patients consult a professional doctor in detail, improve the relevant examination, clarify the degree of development of the disease, and take treatment as soon as possible, so as not to delay the condition of cerebral infarction.