What type of scan is for the brain

The most common types of brain scans are computed tomographic CT scans and magnetic resonance imaging MRI. Doctors frequently request a CT or MRI scan of the brain when they are examining a patient with suspected dementia.

CT scans, which use X-rays to detect brain structures, can show evidence of brain atrophy, strokes and ischemia, changes to the blood vessels, and other problems such as hydrocephalus and subdural hematomas. MRI scans use magnetic fields and focused radio waves to detect hydrogen atoms in tissues within the body. They can detect the same problems as CT scans but they are better for identifying certain conditions, such as brain atrophy and damage from small strokes or subtle ischemia.

Doctors also may use electroencephalograms EEGs in people with suspected seizures, which may occur in some forms of dementia. In an EEG, electrodes are placed on the scalp over several parts of the brain in order to detect and record patterns of electrical activity and check for abnormalities. This electrical activity can indicate cognitive dysfunction in part or all of the brain. Many patients with moderately severe to severe dementia of any sort have abnormal EEGs. An EEG may also be used to detect seizures, which occur in about 10 percent of Alzheimer's disease patients as well as in many other disorders.

Several other types of brain scans allow researchers to watch the brain as it functions. These scans, called functional brain imaging, are not often used as diagnostic tools, but they are important in research and they may ultimately help identify people with dementia earlier than is currently possible. SPECT shows the distribution of blood in the brain, which generally increases with brain activity.

PET scans can detect changes in glucose metabolism, presence of amyloid proteins, oxygen metabolism, and blood flow, all of which can reveal abnormalities of brain function. MEG shows the electromagnetic fields produced by the brain's neuronal activity. Currently, the use of PET to detect the tau protein is only available through research. Clinical trials are research studies that evaluate a new medical approach, device, drug, or other treatment.

As a Stanford Health Care patient, you may have access to the latest, advanced clinical trials. Open trials refer to studies currently accepting participants. Closed trials are not currently enrolling, but may open in the future. See a Stanford specialist to learn about your treatment options. Visit our clinic to make an appointment. It can determine if a shunt is working and detect damage to the brain caused by an injury or a stroke.

MRI of the brain can be useful in evaluating problems such as persistent headaches, dizziness, weakness, and blurry vision or seizures, and it can help to detect certain chronic diseases of the nervous system, such as multiple sclerosis. In some cases, MRI can provide clear images of parts of the brain that can't be seen as well with an X-ray, CAT scan, or ultrasound, making it particularly valuable for diagnosing problems with the pituitary gland and brain stem.

In many cases, a brain MRI requires no special preparation. However, the technician will have your child remove any objects containing metal such as eyeglasses and jewelry because they can produce a bright or blank spot on the diagnostic film. You'll also be asked questions to make sure your child doesn't have any internal metal clips from previous surgery or anything else that might cause a problem near a strong magnetic field.

Electronic devices aren't permitted in the MRI room. To get the highest quality MRI results, your child will need to lie still during the scan. For this reason, sedation may be needed, especially for babies and young kids, who often have trouble staying still for the test.

Sedation is also helpful for kids who have trouble relaxing in an enclosed space claustrophobia. Sedation medicines usually are given through an intravenous IV line small tube in a vein to help a child stay asleep during the entire test. If your child will be sedated, food and liquids will be stopped at a certain point before the MRI to allow the stomach to empty. It's important to notify the MRI technician of any illness, allergy, previous drug reactions, or pregnancy.

You can stay in the MRI room with your child until the test begins, and some centers let parents stay throughout the test. Otherwise, you'll join the technician in an outer room or be asked to stay in a waiting room. An MRI of the brain usually takes minutes to perform. Your child will lie on the movable scanning table while the technologist places him or her into position.

A special plastic device called a coil may be placed around your child's head. The table will slide into the tunnel and the technician will take images of the head. Each scan takes a few minutes. To detect specific problems, your child may be given a contrast solution through an IV.

The solution is painless as it goes into the vein. The contrast highlights certain areas of the brain, such as blood vessels, so doctors can see more detail in specific areas.

The tracer travels through your blood and collects in organs and tissues. The tracer helps your health care provider to see certain areas or diseases more clearly. Then, you lie on a narrow table, which slides into a large tunnel-shaped scanner.

The PET scanner detects signals from the tracer. A computer changes the results into 3-D pictures. The images are displayed on a monitor for your provider to read. You must lie still during the test so that the machine can produce clear images of your brain.

You may be asked to read or name letters if your memory is being tested. You may be asked not to eat anything for 4 to 6 hours before the scan. You will be able to drink water. Always tell your provider about the medicines you are taking, including those bought without a prescription.

Sometimes, medicines interfere with the test results. A PET scan causes no pain. The table may be hard or cold, but you can request a blanket or pillow. A PET scan can show the size, shape, and function of the brain, so your doctor can make sure it is working as well as it should.

It is most often used when other tests, such as MRI scan or CT scan, do not provide enough information. Several PET scans may be taken to determine how well you are responding to treatment for cancer or another illness. There are no problems detected in the size, shape, or function of the brain.

There are no areas in which the tracer has abnormally collected. The amount of radiation used in a PET scan is low. It is about the same amount of radiation as in most CT scans. Also, the radiation does not last for long in your body. Women who are pregnant or are breastfeeding should let their provider know before having this test. Infants and babies developing in the womb are more sensitive to the effects of radiation because their organs are still growing.