CT for encephalitis can detect some of the abnormalities, but not all patients with encephalitis can be detected by CT. CT for encephalitis may show hypointense foci in one or both temporal and frontal lobes, often symmetrically, and may be accompanied by psychiatric symptoms, headache, and fever. For the diagnosis of encephalitis, a lumbar puncture is required and cerebrospinal fluid is obtained for routine and biochemical tests to confirm the diagnosis. Patients with encephalitis do not show positive CT in the early stages. In the mid to late stages, about 50% of patients will show CT imaging changes. For the diagnosis of encephalitis, MRI can detect abnormal signals in the temporal and frontal lobes on one or both sides at an early stage.