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Tuesday, 15 January, 2002, 01:39 GMT
Scan 'could prevent stroke'
A stroke occurs when the oxygen flow to the brain is disrupted
A stroke occurs when the oxygen flow to the brain is disrupted
A simple scan may one day be able to identify people who need surgery to prevent them having a stroke, researchers have said.

Magnetic resonance imaging (MRI) scanning would allow doctors to see when a dangerous build up of plaque had formed, causing clots that can block the arteries supplying blood to the brain, potentially triggering a stroke.

MRI is a technique which can be used to look inside the body. It is particularly useful when looking at the soft tissues.

Researchers from America say more work needs to be done to support the findings of their small study.

There was a clear and consistent association between the condition of the fibrous cap as seen by MRI, and the patient's clinical status

Professor Chun Yuan, University of Washington
But they say MRI could be used to as a non-invasive way to monitor atherosclerosis - the build up of fatty substances in blood vessels which narrows arteries and increases the risk of having a stroke.

This could help identify patients who would benefit from surgery to clear the blocked arteries, they say.

Each year over 100,000 people in England and Wales have a first stroke, around 10,000 of whom are below retirement age.

Around 60,000 people die due to strokes each year.

Blocked arteries

Arteries become blocked when plaque build-up becomes unstable and breaks off, causing a blood clot to form around the broken tissue and blocking blood flow.

If this happens in the arteries of the neck, the carotid arteries, the brain can be deprived of oxygen, causing a stroke.

The research team looked at fibrous 'cap' surrounding the plaque in the carotid arteries.

It can be thick, thin or ruptured. When it is thin, it is more prone to rupturing. MRI scanning can pick up subtle differences between the types.

Researchers used high-resolution MRI to study the condition of fibrous caps in the carotid arteries of 53 patients, including 49 men, with an average age of 71.

All were set to have a surgical procedure in which plaque would be removed from their carotid arteries.

The study found people with atherosclerosis who had unstable plaque were 23 times more likely to have a stroke than people with the same amount of artery narrowing, but no unstable plaque.

In addition to MRI scans, the men were checked to see if they had had a stroke or transient ischeamic attack (TIAs), so-called mini-strokes, within the previous 90 days.


Chun Yuan, professor of radiology at the University of Washington, Seattle led the research.

He said: "There was a clear and consistent association between the condition of the fibrous cap as seen by MRI, and the patient's clinical status.

"There was an association between history of recent stroke or TIA and cap status. Only 9% those with intact caps had a positive stroke/TIA history, compared to 70% of those with ruptured caps.

"For those with intact, but thin caps, 50% had a history of recent stroke or TIA."

He adds that MRI is uniquely suited for repeated examinations of plaque because it is non-invasive.

A spokeswoman for the Stroke Association told BBC News Online: "There are very few MRI scanners in UK hospitals as they are expensive and costly to run.

"In the UK, patients who have symptoms of stroke or TIA, a mini stroke, may be referred to hospital for ultrasound tests. The results of the ultrasound will determine whether the patient has a blocked artery and will benefit from a carotid endarterectomy [the surgical procedure in which plaque is removed from the artery]."

She added that cutting out smoking, sticking to a low-fat diet, keeping weight under control and having regular blood pressure checks would also help reduce the risk of stroke or TIA.

The study is published in Circulation, the Journal of the American Heart Association.

See also:

11 Jan 02 | Health
Aspirin 'could save thousands'
05 Sep 01 | Health
Stroke prevention - for 50p a day
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