MRI-based Assessment of Hippocampal glutamate and morphometric changes in preterm infants at term equivalent age with low birth weight

Background Low birth weight and preterm (PT) infants may have higher risks of poor health. As the key brain region for learning and memory, the normal development of the hippocampus is crucial for cognitive abilities of preterm infants. This study aimed to analyze hippocampal glutamate (Glu) and morphometric changes in preterm infants at term equivalent age (TEA) with different birth weight. Materials and methods Eighty-seven infants (23 full-term (FT) infants and 64 PT infants) participated, born between 2023 and 2025, underwent MRI at TEA. Glutamate chemical exchange saturation transfer (GluCEST) MRI and 3D-SPACE were used to assess hippocampal Glu levels and morphometric changes. The PT cohort was categorized by birth weight: PT infants born at extremely and very low birth weight (PT _ELBW&VLBW ), PT infants born at low birth weight (PT _LBW ) and PT infants born at normal birth weight (PT _NBW ). FT infants born at normal birth weight (FT _NBW ) were included as controls. Results PT _ELBW&VLBW exhibited elevated Glu levels, PT _LBW showed intermediate Glu levels. In infants with normal birth weight, PT at TEA have higher glutamate levels than FT. No differences in bilateral hippocampal Glu levels within each group. The bilateral hippocampal volume, surface area, and long diameter in PT _ELBW&VLBW were all significantly smaller than those in PT _NBW . Morphological analysis revealed rightward hippocampal asymmetry across all PT groups. Conclusion Birth weight significantly influences hippocampal glutamate levels and morphology in PT infants. These findings offer new insights into metabolic variations in preterm neurodevelopment.