Image: In a preterm infant’s brain, an MRI scan can reveal abnormalities that were undetected by previous methods. The scans on the left show normal gray matter, while those on the right show abnormal gray matter (Photo courtesy of Washington University in St. Louis).
For the first time, researchers have used magnetic resonance imaging (MRI) of the newborn brain to calculate the volume of multiple brain regions and to map out regional growth trajectories during the infant’s first 90 days of life.
This new approach to measuring early brain development of infants results in more effective whole brain growth charts and providing the first estimates for growth trajectories of subcortical areas during the first three months after birth.
The study was conducted by researchers from the University of California (UC), San Diego School of Medicine (USA) and the University of Hawaii (Hilo, USA). Assessing the asymmetry, size, and rate of growth of different brain regions could be essential in detecting and treating the earliest signs of neurodevelopmental disorders, such as autism or perinatal brain injury.
The study was published August 11, 2014, in the Journal of the American Medical Association (JAMA) Neurology.
For the first time, researchers used magnetic resonance imaging (MRI) of the newborn brain to calculate the volume of multiple brain regions and to map out regional growth trajectories during the baby’s first 90 days of life. The study tracked the brain growth of full term and premature babies with no neurologic or major health issues.
“A better understanding of when and how neurodevelopmental disorders arise in the postnatal period may help assist in therapeutic development, while being able to quantify related changes in structure size would likely facilitate monitoring response to therapeutic intervention. Early intervention during a period of high neuroplasticity could mitigate the severity of the disorders in later years,” said Dominic Holland, PhD, first author of the study and researcher in the department of neurosciences at UC San Diego School of Medicine.
Clinicians have long monitored brain growth by measuring the outside of the infant’s head with a measuring tape. The findings are then plotted on a percentile chart to indicate if normal growth patterns exist. Even though the measurement is helpful for observing growth, it does not reveal if the individual structures within the brain are developing normally.
On average, researchers found the newborn brain grows one percent each day immediately following birth but slows to 0.4% per day by three months. In general, for both sexes, the cerebellum, which is involved in motor control, grew at the highest rate, more than doubling volume in 90 days. The hippocampus grew at the slowest rate, increasing in volume by only 47% in 90 days, suggesting that the episodic memory development is not as critical at this stage of life.
“We found that being born a week premature, for example, resulted in a brain four to five percent smaller than expected for a full term baby. The brains of premature babies actually grow faster than those of term-born babies, but that’s because they’re effectively younger—and younger means faster growth,” said Dr. Holland. “At 90 days post-delivery, however, premature brains were still two percent smaller. The brain’s rapid growth rates near birth suggest that inducing early labor, if not clinically warranted, may have a negative effect on the infant’s neurodevelopment.”
The study also revealed that many asymmetries in the brain are already established in the early postnatal period, including the right hippocampus being larger than the left, which historically, has been suggested to occur in the early adolescent years. Cerebral asymmetry is associated with functions such as dexterity and language abilities.
Next steps involve continuing to make advances in the application of different MRI modalities to examine the newborn brain. MRI provides high quality images of different types of tissue and does not involve radiation, like computed tomography (CT). Future research will investigate how brain structure sizes at birth and subsequent growth rates are altered as a result of alcohol and drug consumption during pregnancy.
“Our findings give us a deeper understanding of the relationship between brain structure and function when both are developing rapidly during the most dynamic postnatal growth phase for the human brain,” concluded Dr. Holland.
University of California, San Diego School of Medicine
University of Hawaii