Negative MRI means normal, if it is positive, organic lesions are considered. For example, intracranial organic lesions are common in diseases such as brain tumors, cerebral hemorrhage, cerebral infarction, subarachnoid hemorrhage, and encephalitis, and patients may have responsible lesions during cranial MRI. Patients with cerebral infarction can be partially free of imaging changes within a few hours of onset. If a history of cranial tumor is considered, an enhanced cranial MRI scan is routinely examined. This test is a noninvasive test that is preferred for cerebrovascular disease and can also be performed if the patient is considered to have a history of craniocerebral trauma. If the patient is considered to have a history of lumbar disc herniation or cervical disc herniation, the lumbar MRI or cervical MRI should also be routinely examined, and for patients with liver disease, the liver MRI can also be examined, etc