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Updated: Aug 7, 2026
Scanning Dos and Don'ts: Using Magnetic Resonance Imaging in Awake Children Aged 3 to 5 Years to Assess Brain Structure and Function
Published on: March 10, 2026
Regional brain development in serial magnetic resonance imaging of low-risk preterm infants
Andrea U J Mewes1, Petra S Hüppi, Heidelise Als
1Department of Radiology, Brigham and Women's Hospital, Harvard Medical School, 75 Francis St, Boston, Massachusetts 02115, USA. mewes@bwh.harvard.edu
Insights
Early birth impacts white matter development in preterm infants without brain injury, showing decreased volumes. However, gray matter volumes remain comparable to term infants, suggesting a critical period for cortical development.
Area of Science:
- Neuroscience
- Developmental Biology
- Medical Imaging
Background:
- Preterm birth can affect brain development, leading to altered brain tissue volumes.
- Previous MRI studies focused on preterm infants with brain injury, highlighting the need for data on infants without injury.
Purpose of the Study:
- To investigate serial MRI scans of low-risk preterm infants without brain injury.
- To identify specific regions of altered brain development due to early birth.
- To establish normative data for preterm brain development.
Main Methods:
- Serial MRI scans were performed on 23 preterm infants (appropriate for gestational age, no visible brain injury) at 32 and 42 weeks' postmenstrual age.
- Fifteen term infants were scanned for comparison.
- Brain tissue classification and parcellation were used to compare regional brain tissue volumes and assess longitudinal growth.
Main Results:
- At 42 weeks' postmenstrual age, gray matter volumes were similar between preterm and term infants.
- Decreased myelinated and unmyelinated white matter volumes were observed in preterm infants, particularly in the region of the central gyri.
- Gray matter constituted 30% and 37% of brain parenchyma at 32 and 42 weeks' postmenstrual age, respectively.
Conclusions:
- Early birth influences brain development, even in the absence of visible brain injury.
- While cortical gray matter volumes were not decreased, white matter volumes were moderately reduced, indicating an adverse effect on white matter development.
- A rapid increase in cortical gray matter volume in serial preterm scans suggests a critical developmental period.
Objective:
MRI studies have shown that preterm infants with brain injury have altered brain tissue volumes. Investigation of preterm infants without brain injury offers the opportunity to define the influence of early birth on brain development and provide normative data to assess effects of adverse conditions on the preterm brain. In this study, we investigated serial MRI of low-risk preterm infants with the aim to identify regions of altered brain development.
Methods:
Twenty-three preterm infants appropriate for gestational age without magnetic resonance-visible brain injury underwent MRI twice at 32 and at 42 weeks' postmenstrual age. Fifteen term infants were scanned 2 weeks after birth. Brain tissue classification and parcellation were conducted to allow comparison of regional brain tissue volumes. Longitudinal brain growth was assessed from preterm infants' serial scans.
Results:
At 42 weeks' postmenstrual age, gray matter volumes were not different between preterm and term infants. Myelinated white matter was decreased, as were unmyelinated white matter volumes in the region including the central gyri. The gray matter proportion of the brain parenchyma constituted 30% and 37% at 32 and 42 weeks' postmenstrual age, respectively.
Conclusions:
This MRI study of preterm infants appropriate for gestational age and without brain injury establishes the influence of early birth on brain development. No decreased cortical gray matter volumes were found, which is in contrast to findings in preterm infants with brain injury. Moderately decreased white matter volumes suggest an adverse influence of early birth on white matter development. We identified a sharp increase in cortical gray matter volume in preterm infants' serial data, which may correspond to a critical period for cortical development.
