Neuroimaging is a group of techniques that help scientists study the brain’s structure and function. These include magnetic resonance imaging (MRI), computed tomography, and electroencephalography.
Initially, these technologies were met with both enthusiasm and strong skepticism. However, recent applications and studies are showing great promise. For example, fMRI is capable of identifying changes in brain activity that correspond to specific mental states.
The brain produces electrical signals that can be detected and recorded with electrodes placed on the head. The signal patterns can show abnormalities like epileptic seizures or a sleep disorder. EEG is safe and does not cause discomfort.
It is also used in intensive care units to monitor the level of anesthesia, to confirm brain death and to help wean anti-epileptic medications. It can also be useful to monitor somatosensory (touch) and higher cognitive functioning during a clinical study.
The results of an EEG are interpreted by a neurologist or a doctor with specialized training in neurophysiology. The neurologist will use the results along with other diagnostic tests and symptoms to determine the diagnosis and plan of treatment. A patient will usually find out the test results via telephone or a follow up appointment at the doctor’s office. If a person experiences any new weakness, numbness or tingling, it is important to tell the doctor.
Cerebral angiography offers a very detailed, clear and accurate picture of the blood vessels in the brain. This helps your doctor to find blockages or abnormalities in the blood vessels of the head and neck that can cause stroke, clots, or aneurysms.
The procedure is performed under local anesthesia in the groin. A thin plastic tube called a catheter is inserted into an artery that supplies the brain. Then, the neuroradiologist injects dye and takes x-ray pictures of the blood vessels as it flows through them.
This test is used to prepare patients for medical treatment (interventional radiology procedures) by targeting specific blood vessels. For example, a cerebral angiogram is used to find the artery that has blocked the blood flow to a brain tumor or a clot that may be responsible for a stroke. It also is useful in diagnosing vascular conditions such as aneurysms and thromboses. It is the only technique that combines diagnosis and treatment in one procedure.
Magnetic resonance imaging (MRI)
MRI uses magnetic fields and radio waves to create images of organs (like the brain and spinal cord) tissues and the skeleton. It can detect abnormalities that may not be apparent on a standard X-ray.
During an MRI scan, you will lie on a table that moves through the large tube-shaped scanner. The radiologist will inject you with a contrast dye, typically gadolinium. This is to enhance the clarity of certain tissues or blood vessels in the completed images. Gadolinium may cause a reaction in some people.
The MRI magnet creates repetitive tapping and thumping noises that can be distracting, especially for some patients. Earplugs or music can be used to block the noise. You will need to hold very still during the scan, because movement can blur the results. There is no known risk to an unborn baby from MRI. However, if you are pregnant or think you might be, your doctor should be notified.
Neuroimaging techniques allow researchers to study how different parts of the brain interact with each other. They can also reveal changes in the structure of the brain, such as those caused by disease or injury. These methods are important tools for neurology and mental health specialists.
They can show which regions of the brain are activated when a task is performed. For example, widespread activation of the occipital lobe occurs when a subject is given visual stimulation. This part of the brain is involved in processing visual signals from the retina.
Functional imaging has been used to identify many of the processes that underlie psychiatric disorders, such as depression and anxiety. It has also been used to investigate treatment effects in rehabilitation. Despite these significant advances, many challenges remain in functional neuroscience. These include improving spatial and temporal resolution, assessing neurochemical profiles and capturing dynamic brain activity. Additionally, there are ethical concerns regarding the use of functional imaging in a clinical setting.