Brain map could prevent strokes

A grant from the

Neurological Foundation will allow researchers at the

to fine-tune a computer model of cerebral bloodflow that could become a tool in predicting, treating and preventing strokes.

Professor Tim David of the University's Centre for Bioengineering said strokes – the death of brain cells through lack of blood – were the third greatest cause of death and the single greatest cause of disability in New Zealand.

“Developing clinical diagnostic tools for the prediction and prevention of strokes is of the utmost importance,” he said.

Medical imaging techniques like MRI scans form the basis of such tools. Professor David's team has developed a groundbreaking tool which takes into account what he calls “The Goldilocks Effect”.

“This is the brain's ability to regulate its own blood flow, supplying brain cells with not too much blood and not too little; but an amount that's just right for proper functioning. In the fairy tale it's porridge, for us it's blood.”

It was this aspect of the computer model that the $5650 Neurological Foundation grant would test, he said.

In a one-year pilot study starting this month, volunteers would have MRI scans from which individual computer maps of their cerebral arteries would be compiled. During the MRI process the volunteers would be asked to hold their breath - a safe procedure which caused a change in blood flow through the autoregulation process – and have blood flow readings taken. These figures would then be fed into the individual's computer map, and compared with MRI scans taken during breath holding. If the actual scan and computer model did not match up, the computer model could then be adjusted, Professor David said.

The development of a computer model which accurately described an individual's cerebral bloodflow could have several practical applications, he said. It could help doctors decide the best way to treat carotid stenosis, a narrowing of the carotid artery which caused no symptoms until the moment of a stroke. It could be used to predict the likelihood and the severity of a stroke, and possibly even to pinpoint which arteries were at risk of haemorrhage or clots. It could help to assess how much a stroke patient's blood pressure could be changed with drug therapy without depriving the brain of the blood it needed.

Professor David said he started developing the computer model five years ago at the University of Leeds. Since coming to New Zealand two years ago he had been able to make faster progress than would have been possible in the UK, due to the support of proactive funding bodies like the Neurological Foundation.

“I've been surprised at the rate the model has advanced,” he said.

“The Neurological Foundation is great in being a little bit more visionary – in supporting more unusual projects like ours that combine mathematics with medical science. Also, their funding process is responsive: the funds are available quickly, which is important in a fast-moving field. Some funding bodies have a lag of up to three years, whereas scientists have a new idea every three days.”