MRI Study Of Brain Structure In Infants With Global Developmental Delay

Objective:To use structural magnetic resonance imaging to evaluate the abnormal changes of the cerebral cortex and white matter fiber tracts in infants with global developmental delay(GDD).In order to provide imaging basis for early clinical diagnosis.Methods:The GDD group includes 67 infants aged between 112 to 699 days with global developmental delay,who diagnosed in Shanxi Children’s Hospital from December 2019 to March 2022.The healthy control group includes 135 normal developing infants aged between 88 days to 725 days in Shanxi Children’s Hospital from September 2020 to August 2021.Whole-brain T1-weighted MRI scans were carried out with a 3.0T magnetic resonance scanner,which was later processed using Infant Freesurfer to perform MR image processing and cortical surface reconstruction.Two morphological features of the cortical surface were computed,i.e.,the cortical thickness(CT)and cortical surface area(SA),of the 66 brain regions,and hence compared between the GDD group and the healthy control group.In addition,22 infants with global developmental delay who underwent 3D-T1 WI MRI and DTI scans in Shanxi Children’s Hospital from December 2019 to May 2022 were selected as the GDD group,ranging in age from 6 months to 24 months.A total of22 normally developing infants in the same age range of 6-24 months were selected as the healthy control group.The brain extraction tool in FMRIB software library was used to extract brain regions,including template establishment and spatial normalization,so as to obtain the fraction anisotropy(FA),axial diffusivity(AD)and radial diffusivity(RD)parameters of 30 fiber tracts in white matter of bilateral brain.The difference of parameter values between the GDD group and the healthy control group was compared,and the correlation between the DTI parameter values of abnormal fiber tracts in white matter and the score of child neuropsychological development scale was analyzed.Results:In regard to the CT,the healthy control group showed a rapid decrease at first and then a slow increase after birth,and the CT of the GDD group decreased slowly and then keep relatively stable.The GDD group showed bilaterally higher hemispherical average CT than those in the healthy control group.In detail,for the left hemisphere,except that in the entorhinal and temporal poles,which the CT values of the two brain regions were lower than those of the healthy control group,the CT of 26 brain regions in the GDD group were higher than those of the healthy control group(P<0.05).For the right hemisphere,the CT of the entorhinal in the GDD group was lower than that in the healthy control group.Otherwise,the CT of the rest 28 brain regions was higher than those in the healthy control group(P<0.05).In regard to the SA,both groups showed a rapid increase after birth till 23 months,and remain quite stable afterward.The GDD group shows lower SA bilaterally than that in the healthy control group.In detail,SA in the GDD group was lower in most cortical regions of both hemispheres than in the healthy control group(P<0.05),except for the right temporal pole and entorhinal.When testing for the brain asymmetry,we found that the healthy control group showed obvious asymmetry of CT and SA,while only a few cortical regions in the GDD group showed asymmetry.Compared with the healthy control group,DTI parameters of multiple white matter fiber tracts in the GDD group showed abnormal changes,mainly as lower FA value,higher AD value and higher RD value,the difference was statistically significant(P<0.05).After controlling for gestational age,age,birth weight and sex,the verbal scores of the child neuropsychological development scale were positively correlated with the FA values of the bilateral anterior limb of internal capsule(r=0.505,0.470,P<0.05).The fine motor score was negatively correlated with the AD value in the left posterior corona radiata(r=-0.536,P<0.05),fine motor scores were negatively correlated with RD values of right posterior thalamic radiation,left sagittal stratum,right cingulum and right tapetum(r=-0.611,-0.556,-0.593,-0.532,P< 0.05).Conclusion:3D-T1 WI and DTI imaging can show the microscopic changes of the brain structure of infants with global developmental delay,the accumulation of cortical and deep white matter in the regions with abnormal brain structure,and the value of abnormal fiber tracts parameters in white matter is correlated with the score of child neuropsychological development scale.It provides new ideas for quantitative analysis of microscopic changes in brain development and mechanism exploration of neurological dysfunction in infants with GDD,and also provides imaging basis for early clinical diagnosis.