MRI of head and brain stem results 2 yr old

My sons results are as follows

There is boarderline myelination for age with patchy signal in the parietal periventricular white matter which may represent patchy areas of abnormal myelination or unmyelinated white matter or possible gliosis.  Mild thinning of teh body of the corpus callosum is present, likely due to periventricular white matter loss.  Asymmetry in size in the lateral ventricles can be a normal finding, but may suggest asymmetric volume loss.  

Can anyone explain this?  Any info will help.  Thanks