MRI Technique Detects Differences in Brain Structure of Premature Babies Who Develop Abnormalities

With so many preterm infants surviving, there is interest in understanding the effects of preterm birth on brain development. Research has shown that extremely preterm babies later face higher risks of developing brain abnormalities like autism and cerebral palsy. Now, a new study has revealed that premature babies who develop brain abnormalities as teenagers have subtle differences in their brain structure that can be detected on quantitative MRI (qMRI).

The findings of the study by researchers at the University of North Carolina in Chapel Hill (Chapel Hill, NC, USA) show the potential for qMRI, which obtains numerical measurements, to help improve outcomes for the growing numbers of people born preterm. qMRI is a noninvasive technique that generates rich information on the brain without radiation. The researchers used it to assess the brains of adolescents who had been born extremely preterm.

The researchers collected data from MRI scanners at 12 different centers on females and males, ages 14 to 16 years. They compared the qMRI results between atypically versus neurotypically developing adolescents. They also compared females versus males. The comparison included common MRI parameters, or measurements, like brain volume. It looked at less commonly used parameters too. One such example was proton density, a measurement related to the amount of water in the brain’s gray and white matter.

There was no control group of people born after the typical nine months of gestation. Instead, the researchers used the neurotypically developed children for comparison. Of the 368 adolescents in the study, 252 developed neurotypically while 116 had atypical development. The atypically developing participants had differences in brain structure visible on qMRI. For instance, there were subtle differences in white matter related to proton density that corresponded with less free water.

The researchers collected umbilical cord and blood samples at the beginning of the study. They plan to use them to look for correlations between qMRI findings and the presence of toxic elements like cadmium, arsenic, and other metals. The power of qMRI will allow them to study both the quantity and quality of myelin, the protective covering of nerves that is important in cognitive development. They also want to bring in psychiatrists and psychologists to relate qMRI findings to intelligence, social cognition and other outcomes.

“Quantitative MRI in a large dataset allows you to identify small differences between populations that may reflect microstructural tissue abnormalities not visually observable from imaging,” said medical physicist Hernán Jara, Ph.D., professor of radiology at Boston University School of Medicine who was also involved in the study. “This might be the tip of the iceberg since the amount of free water is highly regulated in the brain. The fact that this difference was observed more in females than males may also be related to the known comparative resilience of females as demonstrated in findings from earlier ELGAN-ECHO and other studies.”

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University of North Carolina in Chapel Hill