Brain imaging

Brain imaging refers to the use of various techniques to directly or indirectly image the structure, function, or pharmacology of the nervous system. It is a relatively new discipline within medicine and neuroscience. Brain imaging falls into two broad categories: structural imaging and functional imaging.

Structural Imaging

Structural imaging deals with the structure of the brain and the diagnosis of large-scale intracranial disease (such as a tumor) and injury. Techniques include:

• Magnetic Resonance Imaging (MRI)
• Computed Tomography (CT)
• Diffusion Tensor Imaging (DTI)

Magnetic Resonance Imaging (MRI)

Magnetic Resonance Imaging (MRI) uses strong magnetic fields and radio waves to generate detailed images of the brain. It is particularly useful for imaging soft tissues and is widely used in both clinical and research settings.

Computed Tomography (CT)

Computed Tomography (CT) uses X-rays to create detailed images of the brain. It is often used in emergency settings to quickly identify issues such as hemorrhage or stroke.

Diffusion Tensor Imaging (DTI)

Diffusion Tensor Imaging (DTI) is a type of MRI that maps the diffusion process of molecules, mainly water, in biological tissues. It is particularly useful for imaging the white matter tracts in the brain.

Functional Imaging

Functional imaging is used to diagnose metabolic diseases and lesions on a finer scale (such as Alzheimer's disease) and also for neurological and cognitive psychology research. Techniques include:

• Functional Magnetic Resonance Imaging (fMRI)
• Positron Emission Tomography (PET)
• Electroencephalography (EEG)
• Magnetoencephalography (MEG)

Functional Magnetic Resonance Imaging (fMRI)

Functional Magnetic Resonance Imaging (fMRI) measures brain activity by detecting changes associated with blood flow. This technique relies on the fact that cerebral blood flow and neuronal activation are coupled.

Positron Emission Tomography (PET)

Positron Emission Tomography (PET) uses radioactive substances to visualize and measure changes in metabolic processes, and in other physiological activities including blood flow, regional chemical composition, and absorption.

Electroencephalography (EEG)

Electroencephalography (EEG) records electrical activity of the brain. It is typically non-invasive, with the electrodes placed along the scalp, although invasive electrodes are sometimes used in specific applications.

Magnetoencephalography (MEG)

Magnetoencephalography (MEG) measures the magnetic fields produced by neuronal activity in the brain. It is used to map brain function and to locate regions affected by pathology before surgical removal.

Applications

Brain imaging is used in a variety of applications including:

• Neurology
• Psychiatry
• Neurosurgery
• Cognitive neuroscience
• Psychology

See Also

• Neuroimaging
• Neuropsychology
• Brain mapping
• Cerebral cortex
• Neurotransmitter