Healthcare (Commonwealth Union) – Scientists have developed an advanced method that enables ultra-high-powered MRI scanners to detect subtle abnormalities in the brains of patients with treatment-resistant epilepsy. This groundbreaking approach, used for the first time, has allowed doctors at Addenbrooke’s Hospital in Cambridge to offer surgical procedures that can potentially cure the condition.
Previously, 7T MRI scanners—named for their 7 Tesla magnetic field, which is more than twice as strong as the widely used 3T scanners—were hindered by signal blackspots in critical brain regions. However, a new study published in Epilepsia by researchers in Cambridge and Paris has introduced a technique that eliminates this issue.
In the UK, approximately 360,000 individuals live with focal epilepsy, a condition where seizures originate in a specific brain region before spreading. For nearly a third of these patients, medication is ineffective, making surgery the only possible cure. Epileptic seizures rank as the sixth most common reason for hospital admissions.
For a successful surgical procedure, surgeons must pinpoint the brain lesions responsible for triggering seizures. Identifying these abnormalities through MRI scans significantly improves the accuracy of the procedure, doubling the likelihood of patients becoming seizure-free post-surgery.
Ultra-high field 7T MRI scanners provide significantly sharper brain images and have proven superior in other countries to the NHS’s top 3T MRI scanners in detecting lesions in patients with drug-resistant epilepsy. In fact, many NHS hospitals still rely on less powerful 1.5T scanners. However, a major drawback of 7T MRI scans is the presence of dark patches, known as signal dropouts, which often appear in the temporal lobes—where most epilepsy cases originate.
To address this issue, researchers at the University of Cambridge’s Wolfson Brain Imaging Centre, in collaboration with the Université Paris-Saclay, tested a technique called ‘parallel transmit.’ This method employs eight transmitters placed around the brain instead of a single transmitter, effectively eliminating problematic dropouts.
Chris Rodgers, who is Professor of Biomedical Imaging at the University of Cambridge, says “It used to be the case that MRI scanners used a single radio transmitter, but in a similar way to how single wifi routers leave areas where you will struggle to get a signal, so these scanners would tend to leave blackspots on brain scans where it was hard to make out the relevant tissue.
“Now, by using multiple radio transmitters positioned around the patients’ head – like having a wifi mesh around your home – we can get much clearer images with fewer blackspots. This is important for the epilepsy scans because we need to see very precisely which part of the brain is misbehaving.”
The researchers conducted a study with 31 patients suffering from drug-resistant epilepsy at Addenbrooke’s Hospital, part of Cambridge University Hospitals NHS Foundation Trust (CUH), to determine whether the parallel transmit 7T scanner was more effective than conventional 3T scanners in detecting brain lesions.
Their findings revealed that the parallel transmit 7T scanner uncovered previously undetected structural lesions in nine patients. In four cases, it confirmed the presence of lesions initially suspected on 3T scans, while in another four patients, it ruled out suspected lesions.
Additionally, in 57% of cases, the parallel transmit 7T scanner produced clearer images than traditional ‘single transmit’ 7T scanners. In the remaining cases, both scanners delivered images of similar clarity. Notably, the single transmit scanners never surpassed the parallel transmit version in performance.
Dr. Thomas Cope, a Consultant Neurologist at CUH and a member of the University’s Department of Clinical Neurosciences, indicated that epilepsy that is resistant to anti-seizure medications can significantly affect a patient’s life, often impacting their independence and ability to hold a job. He indicated that they are aware that many of these patients can be cured, but this requires them to precisely identify the source of their seizures in the brain.
