Volumetric Analysis of the Brain Structures of Children with Down’s Syndrome: A 3D MRI Study

Abstract

Down’s syndrome (DS) is one of the most common genetic causes of mental and cognitive retardation. In fact, it results in a number of characteristic neuropsychological and physical symptoms, including mental retardation. The aim of this study was to compare the brain structure volumes of children with DS to those of healthy children using MRI Studio in order to investigate whether there exists correlation between the developmental stages of DS and the results of both the Denver II Developmental Screening Test and magnetic resonance imaging (MRI) quantitative analysis. Five children diagnosed with Down’s syndrome (age range = 2–6 years) were matched for gender and age with five healthy comparison subjects. To analyse the overall and regional brain volumes, high-resolution MRI scans were performed and a morphometric analysis was conducted via MRI Studio software. The MRI T1 volumetric images were normalised using a linear transformation, which was followed by large deformation diffeomorphic metric mapping. Significant decreases (p<0.05) in the volumes of the right pons, cerebellum and left superior frontal gyrus (prefrontal cortex) were observed in the children with DS when compared with the control group (p<0.05). Although decreases were detected in the regional volumes of other brain locations, they were not significant (p>0.05). It was further found that the developmental retardation observed in the children with DS, as detected using the Denver II test, increased due to decreases in the volumes of certain regions of the brain, although this was also not statistically significant (p>0.05). The results of this study generally confirm the findings of prior studies concerning the overall patterns of the brain volumes in children with DS and also provide new evidence of the abnormal volumes of specific regional tissue components among such a population. These results suggest that the brain volume reduction associated with DS may primarily be due to early developmental differences rather than neurodegenerative changes.