Some children will have brain scans which may help identify a cause of epilepsy.
Computerised tomography (CT scan)
This produces very detailed cross-sectioned images of the brain onto a computer.
CT scans show both bone as well as soft issues including the various areas of the brain. The scan may reveal any obvious structural abnormality or damage.
Magnetic resonance imaging (MRI scan)
Using magnetic fields, rather than X-rays, this scan forms an image of the structure of the brain and is more detailed than a CT scan.
It is the most common scan type for children as it is sharper, and can reveal far smaller structural abnormalities. The disadvantage is that it takes longer and is noisy.
Some children may need sedation or anaesthesia prior to an MRI scan as they will have to lie still for some time. They may also be unsettled by the noise or claustrophobic feeling of being in the scanner.
Functional Magnetic Resonance Imaging (fMRI scan)
An MRI scan with functional imaging (fMRI) is able to look at both the brain structures and areas of abnormality, as well as the blood flow in a specific area of the brain.
Actions such as thought, speech, movement and sensation cause an increase in the blood flow to the area in the brain that is activated. This makes the fMRI extremely useful for mapping the brain for its various functions and for locating where seizures start.
Single Photon Emission Computed Tomography (SPECT scan)
During the test a computer collates the images of the brain and shows them in cross sections. These can be added together to form a 3D image.
Because a SPECT scan can show areas of reduced blood flow, it is more likely to pick up brain injury because there is likely to be reduced blood flow to the affected area.
During this test the child is given injection into the blood stream. When scanning is then performed, the blood flow through the arteries and veins in the brain can be traced. If this is done during a seizure, it will show where in the brain the seizures started.
Positive Emission Tomography (PET scan)
PET scans are more precise than SPECT scans. They are able to show how tissues in the brain are functioning and show areas which may be structurally abnormal, that do not show up on an MRI scan. These scans are not widely available.