Researchers have developed ultra-powerful scans that could enable surgery for previously treatment-resistant epilepsy.
Globally, about 50 million people have epilepsy. In England, epileptic seizures are the sixth most common reason for hospital admission. About 360,000 people in the UK have focal epilepsy, which causes recurring seizures in a specific part of the brain.
Many patients successfully treat their condition with medication but for more than 100,000 patients, their symptoms do not improve with drugs, leaving surgery as the only option.
Finding brain lesions, a significant cause of epilepsy, can be tricky. Ultra-powerful MRI scanners are capable of identifying even tiny lesions in patients’ brains. These 7T MRI scanners produce much more detailed resolution on brain scans, enabling better detection of lesions. If surgeons can see the lesions on MRI scans, this can double the chances of the patient being free of seizures after surgery.
But 7T scanners are also susceptible to “dark patches” known as signal dropouts. Now researchers in Cambridge and Paris have developed a new technique to overcome the problem. Scientists at the University of Cambridge’s Wolfson Brain Imaging Centre, and the Université Paris-Saclay, used eight transmitters around the brain, rather than the usual one, to “parallel transmit” MRI images, which significantly reduced the number of black spots.
The first study to use this approach, doctors at Addenbrooke’s hospital, Cambridge, then trialled the technique with 31 drug-resistant epilepsy patients to see whether the parallel transmit 7T scanner was better than conventional 3T scanners at detecting brain lesions.
The research, published in the journal Epilepsia, found that the parallel transmit 7T scanner identified previously unseen structural lesions in nine patients.
The images were also clearer than conventional “single transmit” 7T images in 57% of cases.
As a result, 18 patients (58% of the group) received different management of their symptoms. Nine were offered surgery and one was offered laser interstitial thermal therapy, which uses heat to remove the lesion. Five patients were offered stereotactic electroencephalography (sEEG), a costly and invasive technique for pinpointing lesions using electrodes inserted into the brain.
Dr Thomas Cope, a consultant neurologist at Cambridge university hospitals, said: “Having epilepsy that doesn’t respond to anti-seizure medications can have a huge impact on patients’ lives, often affecting their independence and their ability to maintain a job. We know we can cure many of these patients, but that requires us to be able to pinpoint exactly where in the brain is the root of their seizures.
“Thanks to this new technique, more epilepsy patients will be eligible for life-changing surgery.”
Responding to the findings, Ley Sander, the medical director of the Epilepsy Society, said: “Anything that will improve the lives of people with focal epilepsy that cannot be managed with medication is to be welcomed.
“With each new technical innovation, it is important that clinical and research staff can have access to this equipment to further develop and pioneer new treatments and approaches with colleagues.”
