NEUROIMAGING

Neuroimaging includes the use of different techniques to either directly or indirectly image the structure, function/pharmocolgy of the brain. 

 

 Computed Tomography- Like x-rays, CT scans expose the patient to radiation, although the amount is low and the procedure is safe even if it needs to be repeated several times over the years. The scanner is a large machine, but the patient’s head is not in a confined space as with MRI, which is discussed next. The CT scan is normal in most patients with epilepsy. Brain abnormalities that might be detected are atrophy (a decrease in brain substance), scar tissue, tumors, abnormal blood vessels or abnormal spinal fluid circulation

http://www.med.nyu.edu/cec/diagnosing/diagnostic/ct.html

MRI ( Magnetic resonance Imaging) 

The MRI does not use x-rays, but rather uses a powerful magnet that changes the spin on atomic particles that are normally part of the body, and then measures the changes in the magnetic field as the particles resume their previous course. The patient does not feel anything. The images are a remarkably accurate representation of the brain’s structure. MRI is extremely helpful for identifying brain scar tissue, areas of abnormal brain development (dysplasia), small brain tumors, blood vessel abnormalities, and changes in the brain’s white matter. http://www.med.nyu.edu/cec/diagnosing/diagnostic/mri.html

PET ( Positron Emission Tomography)

PET is a technique that shows the brain’s use of oxygen or sugar (glucose). As with SPECT, a very low, safe dose of a radioactive substance is injected into the patient’s arm and the scanner records its circulation. Not all types of PET scans look alike, but often different colors are used to show areas of higher or lower use of oxygen or sugar.

This test can help to identify the area of the brain from which partial seizures arise. It may be performed in the period between seizures, the interictal period. Unlike the SPECT, PET testing can be done on an outpatient basis, as it is not necessary to perform this test on a patient during or immediately after his or her seizure.

http://www.med.nyu.edu/cec/diagnosing/diagnostic/pet.html

fMRI ( Functional Magnetic Resonance Imaging)

Functional magnetic resonance imaging (fMRI) utilizes a standard magnetic resonance imaging (MRI) machine to identify regions of cerebral function during specific tasks.  The test measures changes in blood oxygen levels associated with increased blood flow to regions of active brain function during a particular task.  Physicians and scientists design protocols in which a patient performs a task repetitively to activate a particular area of brain (for instance, lifting the left index finger).  By analyzing this data, the region or regions of brain involved in performing the task can be identified.  This test is increasingly being utilized, like magnetoencephalography (MEG), in the pre-operative planning of patients undergoing neurosurgical procedures in regions near functional cortex.