New MRI technology enables life-changing surgery for epilepsy patients

New MRI technology enables life-changing surgery for epilepsy patients

A new technique has allowed ultra-powerful magnetic resonance imaging (MRI) scanners to identify tiny differences in patients' brains that cause treatment-resistant epilepsy. In the first study to use this approach, doctors at Adenbrooke Hospital, Cambridge, offering patients surgery enabled them to cure their condition.

Previously, 7T MRI scanners — so called because they operate with a 7 Tesla magnetic field, more than twice the strength of previous 3T scanners — have suffered from signal black spots in crucial parts of the brain. But in research published today inepilepsyResearchers in Cambridge and Paris have used a technique that overcomes this problem.

Around 360,000 people in the UK have a condition known as focal epilepsy, which causes seizures to spread from one part of the brain. A third of these people have persistent seizures despite medication, 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 procedure, they must be able to see the lesions (diseased tissue) in the brain that are responsible for the seizures. Then they can figure out exactly which areas to remove to cure the patient's epilepsy. If surgeons can see the lesions on MRI scans, it can double the chance that the patient will be seizure-free after surgery.

Ultra-high field 7T MRI scanners allow much more detailed resolution for 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 prone to dark spots called signal dropouts. These dropouts usually 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 Center and colleagues at Université Paris-Saclay tested a technique known as "parallel transmission," which uses eight transmitters in the brain instead of just one to avoid the problematic failures.

MRI scanners used to use a single radio transmitter, but in a similar way to individual Wi-Fi routers, they leave areas where you have difficulty getting a signal, so these scanners tend to leave black spots on brain scans where it was difficult to detect the tissue of interest.

By using multiple radio transmitters placed around the patient's head - like a WiFi network in your home - we can get much clearer images with fewer blackspots. This is important for epilepsy scans because we need to be very specific about which part of the brain is misbehaving.

The Paris group's plug-and-play sequences avoid the need to calibrate the scanner at each visit, making it convenient to use these scans for scanning patients. “

Chris Rodgers, Professor of Biomedical Imaging, University of Cambridge

The team tested their approach on 31 drug-resistant epilepsy patients recruited at Addenbrooke Hospital, part of Cambridge University Hospitals NHS Foundation Trust (CUH), to see whether the parallel transmitter 7T scanner was better than conventional 3T scanners at detecting brain lesions.

They found that the parallel transmitter 7T scanner identified previously invisible structural lesions in nine patients. It confirmed suspected lesions detected using 3T scanners in four patients and showed that suspected lesions could not be accounted for in additional additional patients.

Parallel transmitter 7T images were clearer than traditional (“single transmitter”) 7T images in more than half of the cases (57%), and in the remaining cases the images were equally clear. Single-sender scanners never outperformed parallel-sender scanners.

As a result of their results, more than half of the patients (18 patients or 58%) had their epilepsy treatment changed. Nine patients underwent surgery to remove the lesion and one patient was offered laser interstitial heat therapy (where heat is used to remove the lesion). In three patients, scans showed more complex lesions, meaning surgery was no longer an option. Five patients were offered stereotactic electroencephalography (Seeg), a technique to map the lesions using electrodes inserted into the brain, because of the size or location of their lesions. This procedure is not used for everyone as it is very expensive and invasive, and the 7T scans enabled the patients most likely to be helpful.

Dr. Thomas, from the University's Department of Clinical Neurosciences and a consultant at CUH, said: "Epilepsy that does not respond to anti-anxiety medication can have a big impact on patients' lives. Often it affects their independence and their ability to hold down a job. We know we can correct many of these patients.

“7T scanners have shown promise in the last few years since their introduction, and thanks to this new technology, more epilepsy patients are having life-changing surgery.”
When the team asked patients about their subsequent experience, patients reported only minor and occasional negative experiences, such as dizziness upon entering the scanner and additional claustrophobia from the head coil. This suggests that parallel transmission 7T MRI is acceptable for patients.

The research was supported by the Cambridge University Hospitals Academic Fund and the Medical Research Council, with support from the National Institute for Health and Care Research Cambridge Biomedical Research Center.

Dr. Cope is an official fellow at Murray Edwards College, Cambridge. Professor Rodgers is a bye at Peterhouse in Cambridge.

“Once I had the operation, it was obviously the right decision”: Amanda Bradbury

Amanda Bradbury, 29, wanted to be an interior designer when she was younger. She started a course at university, but although it was a subject she really enjoyed, she found herself overwhelmed, struggling to concentrate and becoming increasingly anxious. Eventually it became too much and she had to get out.

What Amanda didn't know was that her problems were caused by a tiny flaw in her brain that caused her to have seizures - called "focal epilepsy".

At first, the most obvious signs of these attacks were auras, distortions in her vision. These started when she was around 19 years old, but her symptoms became more frequent and problematic. She would often become extremely anxious, struggling to concentrate and follow conversations, forgetting things, having difficulty speaking or even swallowing.

“One of the things that would happen before a seizure is that I would get an intense feeling of fear.

This has affected even the simplest things, she says. "I left the house a lot less because of nerves because it can affect your memory when you have a seizure. I would be too nervous to talk because I would be confused. I was just always unsure what was going on."

For some time she dismissed her symptoms. But when she moved to Cambridge to live with her sister, what was happening became harder to ignore.

"Because I lived with someone who knows me, [my sister] could see that certain things didn't make sense. I couldn't concentrate as much, or I would say words that didn't relate to something we were doing."

Encouraged by her sister, she sought medical help. Doctors at Addenbrooke's Hospital in Cambridge diagnosed her with central epilepsy. Suddenly everything made sense to her. But what was surprising was how often she had these attacks. Although she believed she was performing a few times a week, Brainwave recordings revealed that she was actually having them several times a day.

Amanda was given medication to treat her condition, but despite trying three different medications, some of which initially seemed to reduce her symptoms, none of them were ultimately effective. This was when the doctors suggested surgery.

Amanda's lesion was large enough to be visible to 3T MRI scanners (for many patients, the lesions are not clearly visible on these scanners, which is where ultra-high field 7T MRI scanners can help). The lesion was in her amygdala, the part of the brain responsible for controlling emotions, which explained why she felt so anxious before and during an episode.

Because the Cambridge team was able to determine the lesion, surgeons were then able to remove it.

Very soon after the surgery, Amanda felt different – ​​less tired, more energized and less anxious. People around her also noticed a difference as she was able to focus and concentrate more.

She uses the example of an everyday task that seems trivial to most of us to illustrate the difference Operation has made.

“One thing I can do much easier now is clean the kitchen!” she says. “I can stand up, focus on what I’m doing, and chat while I’m doing it.”

She was so used to having seizures and struggling from day to day that it took her disappearance to show her what normality was like. She now works in office administration but wants to get back into interior design as a hobby.

"I want to try to do things that I enjoy, like interior design and things that are artistic. I want to experience those things more."

Although it took her some time to accept her diagnosis, calling it "mentally overwhelming," Amanda is now very open about her epilepsy. Realizing that she was part of a community of people living with the condition, that she wasn't going through these things alone, helped her, and she wants to help others, feel supported.

She also doesn't regret having the surgery. Although it felt like a big decision at the time, she made it clear to herself that she was in safe hands and that this could really help her.

“Once I had the surgery, despite all the healing, it was obviously the right decision,” she says. "Suddenly I realized I could do a lot of other things. It made me start thinking, Oh, what can I do? Things felt a lot more possible, like I can suddenly do so many more things."

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