3D simulation shows benefits of brain cooling

Fresh insight into how the brain responds to medically induced cooling could inform treatments for head injuries and conditions such as stroke.

The study, carried out in 3D simulations, could also help babies at risk of birthing complications.

A newly developed model of cooling's impact on the scalp has shown that the process – routinely used to limit head injury – can prompt a beneficial drop in temperature deep in the brain.

Prof Peter Andrews, of the University of Edinburgh's College of Medicine and Co-Investigator said:

"We had clinically shown that lowering the brain temperature after head injury or stroke helps relieve pressure inside the head, avert swelling and further injury, especially in critical cases".

Prof Ian Marshall, MRI Expert from the University of Edinburgh's College of Medicine and Co-Investigator added:

"Getting vital information such as core brain temperature is a challenge and is only currently possible through expensive MRI scans. A robust model which can predict temperature and blood flow is therefore the need of the hour."

The 3D model, developed by Dr Stephen Blowers and Dr Prashant Valluri of the University of Edinburgh's School of Engineering, is the first to take into account simultaneous flow, heat transfer and metabolism between arteries, veins and brain tissue in three dimensions throughout the organ. The results, obtained as 3D temperature and blood volume maps, could help develop and test therapeutic cooling techniques and inform more focussed clinical trials. The model, named Vapor, takes into account both the vasculature and the porous tissue in the brain and is available freely under opensource license (https://github.com/sblowers/VaPor).

Researchers examined in greater detail than ever before how lowering scalp temperature impacts on blood vessels and tissue throughout the brain.

Using computer simulations, researchers from found that cooling the heads of newborn babies to 10C would enable their core brain temperature to fall from a normal level of 37C to below 36C – which is recognised as low enough to aid recovery.

This could dramatically help babies at risk of long-term damage from birth complications, without having to cool their entire body, researchers say. When applied to adult brains, the model predicted cooling was able to precipitate a potentially beneficial 0.5C drop in-line with what has been observed clinically.

Engineers and medical experts who developed the latest model say it could be modified to mimic the effects of stroke in the brain, or the impact of administering drugs.

The study, published in Scientific Reports, was carried out by researchers at the University of Edinburgh and supported by the Engineering and Physical Sciences Research Council.

Dr Prashant Valluri, of the University of Edinburgh's School of Engineering, who led the study, said:

"Our sophisticated model should enable speedy progress in developing optimum treatments involving brain cooling, and support the development of studies on brain health."

Further Information

Head slice and vessel expansion probability maps
Top Row: An axial (a) and sagittal (b) slice of the head and brain probability maps used for all trials with the VaPor model. The various tissue types were assigned a shade of grey to highlight the segmentation of the domain. Bottom Row: Vessel expansion using RRT Method and diameters from flow. c): Original vessel structure. d) Vessel structure after 2500 iterations of RRT algorithm
Profile of tissue temperature difference of the brain when the scalp temperature is reduced from 33.5 ◦ C to 10 ◦ C in an adult head
Profile of tissue temperature difference of the brain when the scalp temperature is reduced from 33.5 ◦ C to 10 ◦ C in an adult head
RRT generation for a 2D domain at 2500 iterations. The red segments depict a pre-allocated vessel structure. The shaded area has 4× higher perfusion than the unshaded region and, therefore, attracts 4× the number of vessel segments.
RRT generation for a 2D domain at 2500 iterations. The red segments depict a pre-allocated vessel structure. The shaded area has 4× higher perfusion than the unshaded region and, therefore, attracts 4× the number of vessel segments.

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