Focal epilepsy, which causes seizures to spread from a specific part of the brain, affects around 360,000 people in the UK. A third of those have persistent seizures despite medication, known as refractory epilepsy and the only treatment that can cure their condition is surgery. Epileptic seizures are the sixth most common reason for hospital admission.

In order for surgeons to perform this operation, they need to be able to see the lesions (diseased tissue) in the brain responsible for the seizures. Then, they can work out exactly which areas to remove to cure the patient’s epilepsy. If surgeons are able to see the lesions on MRI scans, this can double the chances of the patient being free of seizures following surgery.

Ultra-high field 7T MRI scanners allow much more detailed resolution on brain scans and have been shown in other countries to be better than the NHS’s best 3T MRI scanners at detecting these lesions in patients with drug-resistant epilepsy (and in fact, most NHS hospitals have even weaker, 1.5T scanners). However, 7T MRI scans are susceptible to dark patches known as signal dropouts. These dropouts commonly occur in the temporal lobes, where most cases of epilepsy arise.

To overcome this problem, researchers at the University of Cambridge’s Wolfson Brain Imaging Centre, working with colleagues at the Université Paris-Saclay, trialled a technique known as ‘parallel transmit’, which uses eight transmitters around the brain rather than just one to avoid the problematic drop-outs.