CT examination of the brain is not able to determine whether the patient has insufficient blood supply to the brain. CT examination of the brain is an X-ray examination, which is better than soft tissue for the visualization of human hard tissues. Metabolic diseases are diagnosed. Usually, head CT is the main diagnostic method in the case of head trauma, and it can show whether there is hydrocephalus in the ventricles of the brain. If the patient is considering the presence of cerebral blood supply deficiency, transcranial Doppler and cervical vascular ultrasound of the head should be completed to clarify whether the patient has cerebral blood supply deficiency and cerebral blood flow slowdown.