Measures of Brain Metabolism and Diffusion in Neonates of Diabetic Mothers

ABSTRACT BACKGROUND AND PURPOSE: Maternal diabetes may affect newborns' long-term neurodevelopment and cognitive behavior. Brain biochemistry and white matter fiber tracks may reveal early changes of brain abnormality. The purpose of this study was to compare brain metabolites and fiber structures in infants of diabetic mothers (IDMs) with those of non-diabetic mothers during the early stage of neonatal neurodevelopment. MATERIALS AND METHODS: Pregnant women with diabetes mellitus (DM) and healthy controls were recruited prospectively. Baseline characteristics including maternal and gestational age, weight, height, BMI and types of diabetes were extracted from the mothers and neonates in the clinical record. IDMs and healthy controls underwent scans using a 3T MRI scanner. T₂weighted anatomical images were acquired for voxel positioning. ¹H-MRS from the right frontal lobe and whole brain DTI data were acquired from the participants. Independent sample t-tests were used to compare anthropometric data and a general linear model was used to compare brain metabolites and diffusion measures in the neonates. RESULTS: MRI data were successfully obtained from 77 newborns (41 healthy controls and 36 IDMs). Gestational diabetes was the most common diagnosis (53%), followed by type 2 (33%) and type 1 pre-gestational DM (14%). Weight (p=0.02) and BMI (p<0.01) were significantly higher in mothers with diabetes with earlier birth GA. Myo-inositol measurements were significantly higher (p=0.02) in IDMs versus controls but this was not observed in the excitatory neurotransmitter of GABA and other high concentration metabolites. Mean diffusivity values were significantly higher in the anterior part (p=0.03) and posterior gray matter (p<0.05) of the cingulate gyrus for IDMs compared to controls. Axial diffusivity values were significantly higher (p=0.03) in the anterior part right gray matter of the cingulate gyrus for IDMs compared to controls. CONCLUSIONS: The increase of myo-inositol in IDMs may reflect a compensatory mechanism related to altered blood glucose in order to preserve and promote β-cell growth to enhance the production of insulin. The increase in mean diffusivity is consistent with decreased water diffusion which potentially reflects abnormal changes in myelination and axonal loss. ABBREVIATIONS: AD = axial diffusivity; DM = Diabetes mellitus; FA = fractional anisotropy; GA = gestational age; IDMs = infants of diabetic mothers; MD = mean diffusivity; PMA = postmenstrual age; RD = radial diffusivity; SNR = signal-to-noise ratio; STROBE = The Strengthening the Reporting of Observational studies in Epidemiology.