Composite images from an<unk>  scan. Physicians use<unk>  to assess how risky brain surgery or similar invasive treatment is for a patient and to learn how a normal, diseased or injured brain is functioning. They map the brain with<unk>  to identify regions linked to critical functions such as speaking, moving, sensing, or planning. This is useful to plan for surgery and radiation therapy of the brain. Clinicians also use<unk>  to anatomically map the brain and detect the effects of tumors, stroke, head and brain injury, or diseases such as Alzheimer's, and developmental disabilities such as Autism etc..<unk>  image of the brain of a participant in the Personal Genome Project. Clinical use of<unk>  still lags behind research use. Patients with brain pathologies are more difficult to scan with<unk>  than are young healthy volunteers, the typical research-subject population. Tumors and lesions can change the blood flow in ways not related to neural activity, masking the neural HR. Drugs such as antihistamines and even caffeine can affect HR. Some patients may be suffering from disorders such as compulsive lying, which makes certain studies impossible. It is harder for those with clinical problems to stay still for long. Using head restraints or bite bars may injure epileptics who have a seizure inside the scanner; bite bars may also discomfort those with dental prostheses. Despite these difficulties,<unk>  has been used clinically to map functional areas, check left-right hemispherical asymmetry in language and memory regions, check the neural correlates of a seizure, study how the brain recovers partially from a stroke, test how well a drug or behavioral therapy works, detect the onset of Alzheimer's, and note the presence of disorders like depression. Mapping of functional areas and understanding lateralization of language and memory help surgeons avoid removing critical brain regions when they have to operate and remove brain tissue. This is of particular importance in removing tumors and in patients who have intractable temporal lobe epilepsy. Lesioning tumors requires pre-surgical planning to ensure no functionally useful tissue is removed needlessly. Recovered depressed patients have shown altered<unk>  activity in the cerebellum, and this may indicate a tendency to relapse. Pharmacological<unk> , assaying brain activity after drugs are administered, can be used to check how much a drug penetrates the blood–brain barrier and dose vs effect information of the medication.
Functional magnetic resonance imaging
Functional imaging
Magnetic resonance spectroscopic imaging
Kinetic imaging
Electromagnetic source imaging
Functional near-infrared spectroscopy
Gated SPECT
Current density imaging