Philadelphia, Pa. -- To better understand disease, first understand normal, healthy conditions. That's the rationale behind the first comprehensive magnetic resonance imaging (MRI) study of normal brain development in children. The Children's Hospital of Philadelphia is one of seven pediatric study centers designated by the National Institutes of Health. The $1.7 million grant to Children's Hospital runs from 2000 to 2006.
The study's goal is to establish standard anatomical measurements of normal, developing brain structures, and to correlate those measures with the development of cognitive and behavioral skills. "We know about the normal development of motor skills, but we need to know more about normal brain development," says Edward M. Moss, Ph.D., a pediatric neurospsychologist at Children's Hospital, and co-principal investigator of the grant. "The brain changes quickly during the first five years of life. We'll be able to establish a normal growth curve for the brain."
Children in two major age groups will be studied: infants and preschoolers (up to age four), and children and adolescents (ages five to 18). Children's Hospital will study 50 to 60 children among the total of 500 for the entire multicenter project. In order to study changes over time, all but the oldest children will be followed over a five-year period.
"This study will produce a standardized sample for MRI and neuropsychology studies for decades to come," says physicist John C. Haselgrove, Ph.D., director of the Magnetic Resonance Research Facility at Children's Hospital and principal investigator of the grant.
The children will be assessed with a battery of behavioral, language, motor skills and cognitive tests that will be correlated with the MRI findings. Having systematic data from normal, healthy children will provide a basis for comparison to children with developmental or neurologic problems. For example, explains Dr. Moss, "We could better understand reading problems. If we can compare MRI scans from children with reading problems to scans from children who read normally, we might determine whether reading problems are associated with differences in brain structure. Similarly, we can study brain development in relation to memory skills. Memory has been studied more often in disease states than in normal, healthy subjects."
Studies of other disorders, such as autism or attention deficit-hyperactivity disorder, might also be advanced with the database.
MRI has been used clinically since late 1970s, but only in the past few years have medical institutions moved toward standardizing the equipment they use. MRI is safe and noninvasive; it requires placing a person in a strong magnetic field and measuring the response of nuclei inside the body's molecules. Different tissues respond differently, and computer software processes the magnetic signals into sharp, three-dimensional images of internal structures.
A related technology, magnetic resonance spectroscopy (MRS), sorts out different metabolites -- biological chemicals normally processed in the brain. "We already know that tumors or metabolic diseases show distinctive signatures detectable by MRS," says Dr. Haselgrove. Some of the children to be studied at Children's Hospital will also be examined by MRS to provide normal data on brain metabolites.
Although the procedure is noninvasive, a person must lie motionless for eight to 10 minutes while the MRI machine scans the brain. For babies, the test will be performed as they sleep. Children up to age 7 who will be awake during the procedure will first be familiarized with the equipment by lying in a "mock magnet" facility that trains them to lie still in practice for the actual scan. A mounted mirror allows the child to watch a video, which goes blank temporarily if the child moves too much. "We've found that this apparatus is very effective in preparing children for the actual scan," says Dr. Haselgrove.
The MRI study at Children's Hospital will be coordinated by the Children's Clinical Research Institute, a unique academic contract research organization established at The Children's Hospital of Philadelphia to conduct high-quality clinical research that improves the health care of children.
The Children's Hospital of Philadelphia, the nation's first children's hospital, is a leader in patient care, education and research. This 373-bed multispecialty hospital provides comprehensive pediatric services, including home care, to children from before birth through age 19. The hospital is second in the United States among all children's hospitals in total research funding from the National Institutes of Health.