For most diseases of the brain, MRI is superior to CT. Because MRI is clearer, especially for lesions in the posterior cranial fossa, when CT is performed, there may be artifacts in the brainstem and cerebellum because of the skull base artifacts. At present, many hospitals have magnetic susceptibility imaging, and the effect of magnetic susceptibility imaging for brain hemorrhage is basically equal to that of CT. However, there are many hospitals that do not have MRI with magnetic susceptibility, so there is a vulnerability for early detection of cerebral hemorrhage. It is recommended that if the patient has a sudden onset of the disease, the patient should first check the head CT to rule out brain hemorrhage and then further check the head MRI to confirm the diagnosis.