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New brain imaging at Pitt gives a better picture
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The brain image of Dan Stunkard shows how motor nerves on the right side of his brain, in yellow, are much more sparse after damage from an ATV accident than those on the left side, in green. -
Dan Stunkard of New Castle is partially paralyzed after an ATV accident in 2010.
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Dan Stunkard knows he is not the man he used to be.
But he's grateful to be a man with any kind of future at all.
In August 2010, the New Castle construction worker was riding his ATV outside Ellwood City when he lost control and was thrown headfirst onto the ground.
He wasn't wearing a helmet and suffered serious brain injuries that mean he still can't use his left hand and has limited movement of his left arm, even though he has regained the ability to walk.
Cradling his 1-year-old daughter Danni Lynn at his mother's home recently, he talked quietly to her as she stared adoringly at him.
"Daddy loves his girl, huh? Thank God they saved me at the hospital, huh? So I could be with you and see you grow up? I'd have hated to miss that -- see you getting married someday, in a pretty wedding dress. Daddy's going to stop now, before he starts crying."
PG VIDEOMr. Stunkard, 33, is one of more than 1.5 million Americans who get brain injuries each year, from fatal blows to mild concussions.
But he is highly unusual in being one of the few who knows exactly which cables in his brain are broken.
His insight comes from a new form of brain imaging developed at the University of Pittsburgh called high-definition fiber tracking, or HDFT. The scans can produce highly detailed color-coded pictures of which connections from one part of the brain to another have been damaged.
As described in a study being published today in the Journal of Neurosurgery, doctors could see that many of the axons controlling Mr. Stunkard's left leg were still intact, but that he had lost almost all the connections controlling his left hand.
Before his laboratory developed the new imaging method, Pitt scientist Walt Schneider said, "the standard clinical report after a brain injury like this was, 'You have some swelling in the brain.' What did it mean? We didn't know. What was the prognosis in six months? We didn't know.
"This is a really unsatisfying report for someone who may never work again in their lives."
But with high-definition tracking, he said, "we could say to this patient that the good news is, most of your cables are fine, so we don't expect any major problems with affect, memory and language. But there was serious damage to your motor tracts, and you've taken a really bad hit on your hand, and we don't know if it will come back. And although your leg has a substantial loss of fibers, it still suggests with rehabilitation training that you're going to get a lot of functionality back."
That in fact has been Mr. Stunkard's outcome over the 18 months since his accident.
He can walk, although he has to swing his left leg forward and has trouble with his balance. And while he has very slight movement in his left hand, it is still not able to function normally.
He demonstrated how he can raise his arm slightly above his shoulder, laboriously turn his wrist, and "I can do the biceps a little bit, but it feels like it weighs a million pounds," he said, wheezing with the effort.
High-definition fiber tracking is carried out on an advanced MRI machine but uses a complex new set of mathematical calculations to produce its images. It is based on a technique called diffusion spectrum imaging that was developed by neuroscientist Van Wedeen at Massachusetts General Hospital.
HDFT produces much more accurate pictures than its older cousin, which was known as diffusion tensor imaging, or DTI, Mr. Schneider said.
The pioneering work with DTI could reveal the outline of large brain tracts, Mr. Schneider said, but it could not follow a set of nerve fibers when they crossed over others. "The analogy would be, if you were taking the eye-in-the-sky model of a camera and you were trying to follow someone on the ground, if every time they crossed an intersection, you lost them, it would be of no value" when the aim was to track the car's entire journey.
HDFT allows researchers to follow a nerve fiber from its origin to its endpoint -- and to see when an injury has really cut the connection. Where DTI measured six parameters of water molecules in the brain, Mr. Schneider said, HDFT measures 362, a major reason it creates such sharp pictures.
The new imaging method grew out of a worldwide competition hosted by Mr. Schneider's lab in 2009. Teams from 168 nations took on the challenge of trying to produce the best picture possible using data from diffusion spectrum imaging and other techniques. The winner was Fang-Cheng Yeh, who has since been hired at Carnegie Mellon University, and his approach was developed into the current technique.
Mr. Schneider and UPMC neurosurgeon David Okonkwo said that for now, HDFT is limited to telling a patient how severe his brain injuries are. One day, they hope it will be used to guide treatments that may help the brain regrow its broken connections.
The imaging is also starting to be used by neurosurgeons who have to remove tumors or aneurysms, to help them avoid injuring sensitive bundles of neurons when they operate.
And it is being used by some scientists for basic brain research. Marlene Behrmann, a noted cognitive psychologist at CMU, published a paper last week that used HDFT to reveal new details about how we pick out what to look at within our visual fields.
Her team's paper, published in the Journal of Neuroscience, showed that when we look at objects in specific areas -- say, the upper right or lower left of our visual fields -- that selective attention is governed by separate bundles of fibers that radiate from the brain's parietal lobes, which oversee spatial relationships, to the occipital lobes, which process vision.
HDFT "offers enormously greater precision than the technologies that we were using up until a year ago," the CMU scientist said.
The next big challenge will be for researchers to find drugs or other treatments that can effectively heal brain injuries, Dr. Okonkwo said.
The search has been frustrating. Scientists have identified 28 treatments that worked in mice, but all of them have failed in human trials, he said.
The latest trials, under way now, are testing the hormone progesterone as a possible treatment for brain injuries. Doctors in the United States, Israel, Argentina, Russia and western Europe have signed up 350 patients with brain injuries that were severe enough to put them in a coma, who are being treated with progesterone or a placebo.
UPMC has enrolled more of these patients -- 24 -- than any other center. The multicenter study hopes to enlist 1,200 patients altogether and publish full results next year, Dr. Okonkwo said.
Mr. Stunkard also longs for the day when there might be an effective treatment for him.
"I wonder if there's something they could do to heal those fibers that are broken. That's been my hope from day one," he said. "My oldest son said he maybe wants to become a brain surgeon so he can cut my head open and fix me. I hope so. Maybe by the time he's old enough, he'll be able to do that."
Mr. Stunkard's recovery is still a work in progress.
The accident has damaged his life in other ways, too. The father of three children, he is in the midst of getting a divorce from his wife, who was also injured in the ATV accident, and he takes medication for depression, to stimulate his brain, and to prevent restless leg movements.
His dream for the future?
"I'd love to be able to start using my hand and arm again and working and making money and taking care of my kids, and start living my life again. Because I did have a good life for a long time. Just living life, fishing, hunting, I loved everything outside, and now I'm just stuck in the house, and I can't even go to work.
"I just wish I would have had a helmet on, for sure, and I wish I hadn't been drinking beer and riding a quad.
"If I see kids out here in the neighborhood riding their quads around without helmets on I go up and tell 'em, 'Hey, you don't want to end up like me -- put a helmet on; it'll save your life, that's for sure."
First Published March 2, 2012 12:00 am
