Researchers in Canada have found a new way to use magnetic resonance imaging (MRI) to detect tiny lesions in the brain of patients with severe epilepsy caused by focal cortical dysplasia. Automated computer programmes can spot lesions that were not detectable using standard methods. It's hoped that this will improve the accuracy and efficacy of surgery to treat epilepsy in these patients.

Focal cortical dysplasia is a condition where small areas in the brain do not develop normally. In these zones, called lesions, the white matter layer (responsible for information transmission) is thicker than in normal brains, and the division between this layer and the grey matter (responsible for information processing) is blurred. These lesions have impaired function, and sometimes this damaged tissue can become a seizure focus. Removing the lesion may therefore treat the epilepsy.

Dr Andrea Bernasconi and colleagues at McGill University in Montreal used high-resolution MRI scanning combined with computational techniques to detect lesions in 23 patients with focal cortical dysplasia and 30 healthy controls.

Lesions caused by focal cortical dysplasia are not always easy to detect visually on the scan. In this study, published in January 2006 in Epilepsia, the researchers therefore used a computer programme to process the MRI scans, in order to find even the really small ones. These new methods could reduce the complexity and cost of evaluating patients for surgery, and might improve the efficiency of surgical treatment. They could also improve understanding of the causes of epilepsy.

The improvement of high-resolution MRI in recent years has changed the pre-surgical evaluation of patients with epilepsy who do not respond to anti-epileptic drugs. MRI is now very important in localising lesions that may be causing seizures. As surgical techniques improve, and doctors realise the importance of treating intractable seizures earlier rather than later, especially in children, surgery for epilepsy is being increasingly used. Epilepsy Research UK is funding a study looking at some of the side effects of this surgery on memory and verbal function in children - click here to find out more.

Read more about the Canadian study here