<unk><unk>  (CT) has become the diagnostic modality of choice for<unk>  trauma due to its accuracy, reliability, safety, and wide availability. The changes in microcirculation, impaired auto-regulation, cerebral edema, and axonal injury start as soon as<unk>  injury occurs and manifest as clinical, biochemical, and radiological changes. Proper therapeutic management of brain injury is based on correct diagnosis and appreciation of the temporal course of the disease process. CT scan detects and precisely localizes the intracranial hematomas, cerebral contusions, edema and foreign bodies. Even in emergency situations, when a<unk>  injury is minor as determined by a physician's evaluation and based on established guidelines, CT of the<unk>  should be avoided for adults and delayed pending clinical observation in the emergency department for children. Many people visit emergency departments for minor<unk>  injuries. CT scans of the<unk>  can confirm a diagnosis of skull fracture or brain bleeding, but even in the emergency department, such things are uncommon and not minor injuries, so CT of the<unk>  is usually not necessary. Clinical trials have shown the efficacy and safety of using CT of the<unk>  in emergency settings only when indicated, which would be at the indication of evidence-based guidelines following the physical examination and a review of the person's history. Concussion is not a routine indication for having brain CT or brain MRI and can be diagnosed by a healthcare provider trained to manage concussions. People with concussions usually do not have relevant abnormalities about which brain imaging could give insight, so brain imaging should not routinely be ordered for people with concussions. If there is concern about a skull fracture, focal neurological symptoms present or worsening symptoms, then CT imaging may be useful. MRI may be useful for people whose symptoms worsen over time or when structural pathology is suspected. CT of the<unk>  is sometimes used for people who have sudden hearing loss. However when there are not other neurological findings, a history of trauma, or a history of ear disease, CT scans are not useful and should not be used in response to sudden hearing loss. CT of the<unk>  is also used in CT-guided stereotactic surgery and radiosurgery for treatment of intracranial tumors, arteriovenous malformations and other surgically treatable conditions.
Computed tomography of the head
Brain biopsy
Hemoencephalography
Magnetic resonance imaging of the brain
Lumbar puncture
Radionuclide cisternogram
Ultrasound-guided lumbar puncture
Intracranial pressure monitoring