Abstract: Objective To observe the changes of white matter by using diffusion tensor imaging(DTI ) in developmental delay children with normal routine MRI results.Methods Twenty patients (aged 1 2-3 6 months)with developmental delay and the twenty cases of month-old matched normal development children were studied by conventional MRI and DTI technology. Fractional anisotropy(FA)and mean diffusivity(MD)values were measured in five regions of deep white matter and four regions of shallow white matter.Comparison were made in FA and MD values of developmental normal and development delay children.Results FA value in shallow white matter of developmental delay children was lower than that of control group (P<0.05), MD values in shallow white matter and corpus callosum knee of developmental delay children was higher than that of control group (P<0.05).Conclusion DTI may quantify the injuries of white matter microstructure in developmental delay children with normal routine MRI results.

Key words: developmental disabilities, diffusion tensor imaging, leukoencephalopathies