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Technology allows doctors to peek inside baby's brain Add to ...

Gabriel Sengara was only a few days old when an ultrasound showed that fragile blood vessels in his brain had ruptured.

The bleed was deemed severe and, at first, doctors couldn't tell his parents what it would mean for their son, a twin who was born eight weeks early. His tiny brain was still under construction and vulnerable to damage. His mother, Heather, feared the worst.

"I'm a registered nurse," she said. "I work in emergency and lots of people come in with strokes and bleeds into their brains that are catastrophic."

When his condition stabilized, Gabriel was cocooned in a special incubator designed to slip easily into a magnetic resonance imager. Steven Miller, a neurologist at BC Children's Hospital, used it to peek inside the baby's brain and get a far clearer picture of the extent of Gabriel's injuries than was possible with the ultrasound.

Dr. Miller, senior clinician scientist at the Child & Family Research Institute, is part of large international effort to better understand the impact of brain injuries in newborns using the latest imaging technology. One of their goals is to find ways to protect the brains of premature babies so development can proceed as naturally as in the womb.

If a newborn brain suffers an injury from oxygen deprivation, bleeding or a stroke, it may block normal development in the parts of the brain involved in sight, hearing, movement and memory. Between 25 and 50 per cent of children with very low birth weights, for example, have developmental and visual deficits. Dr. Miller and his colleagues want to learn how to prevent these injuries, sustained in the womb or in the first days of life, from cascading into more pervasive damage that can lead to cerebral palsy, epilepsy, problems with speech, learning difficulties and cognitive impairment. "While the newborn brain is vulnerable to damage it also has an incredible capacity for repair. Our goal is to identify ways to promote repair and recovery," he said.

For instance, Dr. Miller's colleague in California, Donna Ferriero, is exploring whether erythropoietin or EPO, a growth factor, can coax newborn brain cells that have been affected by a stroke to continue their development. Other researchers are looking at additional compounds.

Dr. Ferriero said the aim is to develop "cocktails of solutions" that could repair injuries before they block the normal development of young brains.

That development undergoes dramatic changes in the first few weeks of a premature baby's life. If you look at an MRI scan of an infant born at 29 weeks, and one taken 11 weeks later, around the expected time of birth, it is hard to believe it is the same child.



Premie Brain development at 29 and 40 weeks. Premature newborns undergo dramatic brain growth and development. The first scan shows the brain of an infant born at 29 weeks. The second one was taken 11 weeks later, around the expected time of birth.The dark ribbon on the surface of the brain is the cortex, the cells we use to think, move and react. It has far more folds in the second scan, a sign of healthy development.



The cortex, the dark layer on the surface of the brain that we use to think, move and react, initially looks like a rounded coastline. Eleven weeks later, the coastline is marked by dozens of deep inlets and coves. This new, far more complex geography is a sign of a maturing brain.

Usually, this growth occurs when the baby is still in the womb. Dr. Miller and his colleagues want to make sure it happens as naturally as possible in intensive-care nurseries. Could how the infants are fed, kept hydrated and treated for infections affect their brain development?

The goal, Dr. Miller said, is to find out "how can we use these tools in a way that is brain protective and that would optimize brain development and allow it to proceed as normally as possible."

Inducing hypothermia in term newborns with signs of serious brain injuries, for example, has been found to significantly reduce permanent damage if it is done within six hours of birth. The 72 hours of cooling seem to give their brains a break, slowing down their metabolism at a time of crisis.

Scientists are now investigating whether induced hypothermia will also work with premature babies and whether there are still benefits if the treatment is started more than six hours after the injury.

"Neuroprotection is a reality," Dr. Miller said. "The question is how do we make it better?"

In addition to understanding the newborn brain and the unique types of injuries that occur either during gestation or around the time of birth, they are also studying how these injuries evolve over time.

Premature babies, they have learned, tend to suffer damage to their white matter, which connects different parts of the brain and allows those parts to communicate with each other. That's different from term babies - their injuries tend to affect the grey matter that makes up the structures of the brain.

Dr. Miller wants to be able to scan the brains of premature babies like Gabriel and offer a prognosis that would either reassure families or help them prepare for the extra care, therapy or treatment their children may need as they grow up.

The study, funded by the Canadian Institutes of Health Research, began in 2006 and involves taking brain scans of 175 premature infants, one shortly after birth and a second one around the baby's expected due date. The children are assessed at 18 months, and again at three, 4.5 and eight years of age. Dr. Miller, who also works at the University of British Columbia and is part of NeuroDevNet, a federally funded network of scientists who study brain development in children, has found roughly one in three premature babies have signs of white matter injuries. He wants to see if there is a link between the severity of those injuries and developmental problems.

His preliminary assessments about Gabriel and his twin brother Crosby were reassuring, Ms. Sengara said. Their brains were developing nicely.

The babies were born May 21 at 32 weeks gestation. Crosby was the baby the family was initially most worried about. He had stopped growing in the womb, so doctors decided to deliver the brothers early, by cesarean section. Gabriel was born first, and weighed 3 pounds 9 ounces. Crosby was only 2 pounds 4 ounces, but cruised through his first few days.

Although Gabriel looked more robust, he had difficulty breathing and one of his lungs collapsed. Plus, he suffered the bleeding in his brain.

The first scan showed that Gabriel's ventricles - fluid-filled cavities in the brain - had grown in size after the blood from the ruptured vessels seeped into them. By the second scan, they had started to shrink, Ms. Sengara said. This meant Gabriel probably would not need a shunt to help with drainage.

"It was definitely a relief," the babies' father, Michael Sengara, said. He and his wife were able to take the babies home on July 11. The boys are doing well and are steadily putting on weight. "It made me feel, 'Okay, we can get on with raising our sons,' " he said.

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Follow on Twitter: @AnneMcIlroy

 

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