Epilepsy is a common neurological disorder that has a varied presentation and requires two or more unprovoked seizures at least 24 hours apart for diagnosis. MRI is the modality of choice for epilepsy, most often investigating for an underlying cause, especially in adults.
Epilepsy is very common, with approximately 3% of the population affected at some point in their life .
Epilepsy syndromes can be generally divided into two broad categories :
- generalized, e.g. absence epilepsy, tonic-clonic, myoclonic
- partial (localization-related), can progress to generalized
- temporal lobe epilepsy
- extratemporal epilepsy
There is a wide range of causes, however, in adults with new onset of seizures ~50% will not have a determinable cause . The International League Against Epilepsy (ILAT) have proposed the following classification :
- idiopathic: epilepsy due to an underlying single gene condition or complex inheritance (seizures as the only manifestation)
- cryptogenic: unknown cause
- provoked epilepsy: e.g. secondary to fevers, head trauma, drug-induced
- predominantly genetic/developmental causation
- predominantly acquired
MRI is the modality of choice. Please see articles on specific conditions listed above for imaging features. There are a number of MRI protocols that can be used to investigate patients with seizures.
SPECT perfusion brain
If performed during the crisis, it can be useful for localizing the epileptogenic focus .