Grad student Brooks Lindsey adjusts brain helmet on volunteer.

A prototype “brain helmet” that provides real-time images of major
blood vessels may enable emergency personnel to perform quick scans of
potential stroke victims’ brains, according to a team of Duke
University bioengineers who developed the device.

For patients suspected of having a stroke, the speed of diagnosis and
subsequent treatment can make the difference between survival and death
or disability.

Using 3-D ultrasound technology that they had earlier developed, the
Duke team built a prototype device that positions ultrasound “wands,”
or transducers, against the temples on either side of the head. Duke
graduate student Brooks Lindsey designed a system that allows a
computer to assemble both streams of ultrasound images into a
three-dimensional color movie of the vessels and blood flow within the
brain.

“We were able to demonstrate the feasibility of an ultrasound brain
helmet producing multiple, simultaneous, real-time, three-dimensional
images of the brain’s blood vessel distribution,” Lindsey said. He
presented the results of the latest experiments at the recent Society
of Photo-Optical Instrumentation Engineers’ annual Medical Imaging
scientific sessions in Orlando. He had previously published a paper on
the development of the helmet in the February issue of the journal
Ultrasound in Medicine and Biology.

The most common type of stroke is caused by a blockage in a vessel in
the brain. The only approved drug for this kind of stroke, a
clot-buster known as tPA, must be given shortly after the onset of
symptoms. However, before this kind of treatment can begin, physicians
must scan the brain in a hospital with time-consuming imaging
techniques such as MRI or CT to ensure the stroke is not the result of
a bleed in the brain, which would be exacerbated by the clot-buster.

“We can foresee a time in near future when the brain helmet could
transmit its images from a remote hospital, or from an ambulance,
through cellular networks or the internet to the neurological team at a
stroke center,” said bioengineer Stephen Smith, director of the Duke
University Ultrasound Transducer Group and senior member of the
research team. “Speed is important because the only approved medical
treatment for stroke must be given within three hours of the first
symptoms.”

Unfortunately, the researchers said, studies have shown that it takes
an average of four hours for a potential stroke patient to receive a CT
scan. They estimate that a brain helmet scan can be completed in 15 to
30 minutes.

The latest advance is an extension of the findings of Duke
bioengineering graduate student Nikolas Ivancevich, who developed a
strategy to overcome what has in the past been a major obstacle to
using ultrasound to get clear images of the brain and the structures
within – the skull itself.

The Duke laboratory has a long track record of modifying traditional
2-D ultrasound – like that used to image babies in utero – into more
advanced 3-D scans, which can provide more detailed information. After
inventing the technique in 1991, the team has shown its utility in
developing specialized catheters and endoscopes for imaging the heart
and blood vessels.

Lindsey tested the brain helmet prototype on two healthy volunteers to
assess its ability to accurately provide images of the major vessels of
the brain.

“Not only were we able to see in color real-time images of the blood
vessels, but we observed the direction of blood flow,” Lindsey said.
“Seeing flow is one of our main goals, since it would help clinicians
find the location of the stroke.”

According to the American Stroke Association, stroke is the third
leading cause of death after heart disease and cancer. More than
780,000 Americans suffer a stroke each year, and it is estimated that
it cost the U.S. health care system more than $65 billion for
stroke-related medical care in 2008.

The team is now designing the next generation prototype with an eye
toward reducing the size of its components and improving the efficiency
of the signal from the transducers.

Smith’s laboratory is supported by the National Institutes of Health.
Other Duke members of the team were John Whitman, Ned Light, Matthew
Fronheiser, Heather Nicoletto and Daniel Laskowitz.

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