Dementia scan could boost UK diagnosis rates

Ultra-fast MRI scans taking under seven minutes could double NHS dementia testing capacity and help boost diagnosis rates across the UK, experts have said.

Scientists have developed a way to cut MRI scan times from 20–30 minutes to less than seven minutes, tackling a key bottleneck in dementia diagnosis, where one in three people never receive one at all.

The technique uses advanced physics to gather more information simultaneously during the scan, reducing total time by almost two thirds. When set-up times are included, the method could at least double capacity across NHS hospitals.

The research was developed by UCL’s Functional Imaging Laboratory and part-funded by Alzheimer’s Society.

Professor Nick Fox, a neurology expert who led the team, said the approach could transform access to vital diagnostic tools.

“This is really exciting. It means that we can make MRI scans — that people deserve to have — much, much more available,” he said.

“One in three people don’t get a dementia diagnosis at all, we estimate. And for those people who do, there are long delays and the recommendation that everybody should have a scan doesn’t happen.

“This could at the very least double the number of MRI scans we can do. There’s no reason why this approach can’t be used across nearly all scanners across hospitals in the UK.”

Current guidelines recommend brain imaging to rule out other causes of cognitive decline or identify the specific type of dementia.

Many patients, however, never receive a scan, and those who do are often given computerised tomography (CT) scans, which provide less detailed images than MRI.

Magnetic resonance imaging (MRI) uses a strong magnet to align protons in the body before knocking them out of position with radio waves.

As the protons return to alignment, sensors detect the released energy to map tissue types and create detailed brain images.

Lying still in the scanner can be particularly difficult for patients with memory problems or claustrophobia. Any movement can blur images, sometimes making them unusable and requiring a repeat scan.

The team tested the faster method on 92 volunteers.

Three neuroradiologists reviewed anonymised scans without knowing which were fast or standard and found the shorter scans were equally reliable for diagnosis.

“What we found was that, when we didn’t tell them which scans were fast or standard, experienced neuroradiologists couldn’t tell the difference,” Prof Fox said.

“The diagnostic ability was just as good, and in some cases slightly better because there was less blurring from people moving. It made much more difference which radiologist looked at your scan, or which day of the week it was.”

Latest NHS data for August showed 66 per cent of people living with dementia were thought to have a diagnosis, meaning one third remain undiagnosed.

Prof Fox said the NHS and government should be more ambitious about not only detecting dementia but identifying the specific cause.

“Saying ‘it’s dementia’ is like saying ‘it’s a rash’. If you went to see your GP, you wouldn’t accept them just saying ‘yes, it’s a rash’. You’d want to know if it’s cancer, eczema, something else,” he said.

“Dementia just means brain failure, it’s not working in the way it should anymore. But the underlying cause could be Alzheimer’s disease, strokes, lots of different things.

“We can only make progress if we give people an accurate diagnosis and a much more timely, rapid one.”

Scans are used alongside cognitive tests to identify the type of dementia. A scan might show past strokes or shrinkage in brain areas linked to memory, such as those affected in Alzheimer’s disease.

Labour’s recent 10-Year Health Plan for England said the UK is “far behind other countries in the levels of CT, MRI and positron emission tomography (PET) scanners for its population”.

The UK has 8.6 MRI scanners per million people — the lowest among comparable nations.

The 2023/24 National Audit of Dementia found that 44 per cent of patients attending specialist memory assessment services had a brain scan, with rates varying from 0–90 per cent depending on the service. In 2021, only 31.8 per cent of scans for suspected dementia were MRI.

MRI scanners cost around £1m. Prof Fox said many hospitals could use the faster method and boost capacity with little or no extra cost, although some may need a software update.

The researchers now plan to work with hospitals to trial the technique, which could also be adapted for other types of body imaging.