Jeong-Won Jeong PhD, Presenter: Nothing to Disclose

Ajay Kumar MD, MBBS, Abstract Co-Author: Nothing to Disclose

Senthilnathan Sundaram MD, Abstract Co-Author: Nothing to Disclose

Harry T. Chugani MD, Abstract Co-Author: Nothing to Disclose

Diane C Chugani PhD, Abstract Co-Author: Nothing to Disclose

To study white matter (WM) properties in young children with autism spectrum disorder (ASD) and developmental delay (DD), we performed tissue-specific, smoothing-compensated (T-SPOON) analysis which is optimized for the voxel-based morphometry study.

Thirty-one children with ASD (mean age: 5±1.7 years; 28 males), 11 children with DD (mean age: 4.4±1.7 years; 9 males), and 14 typically developing children (TD, mean age: 5.5±1.9 years; 12 males) underwent diffusion tensor imaging, to create fractional anisotropy (FA) and mean diffusivity (MD) images. To minimize the partial volume artifacts near the edge of WM, the WM was first segmented from the b0 image and used to extract WM only maps of FA and MD image. The WM masked FA, MD, and WM image were spatially normalized to MNI space using SPM DARTEL, and smoothed at 8 mm FWHM Gaussian. The smoothed-normalized-masked FA and MD images were then divided by the smoothed-normalized WM image to correct blurring artifacts caused by the spatial smoothing. The resulting FA and MD images were separately analyzed by voxel-based ANCOVA at a cluster size threshold of >30 voxels and p-value of < 0.05, corrected for multiple comparisons.

Compared with the TD, the ASD and DD showed significantly reduced FA in bilateral uncinate, arcuate, inferior fronto-occipital fasciculi, inferior longitudinal fasciculi, and corpus callosum. The reduction was larger in the DD group. Furthermore, the DD group also showed significant FA reduction in bilateral thalami, cinguli, amygdale and midbrain. Compared with the ASD group, the DD group showed significant FA reduction in bilateral uncinate and amygdala. No significant MD difference was found in “TD vs. ASD” and “ASD vs. DD” group, but the DD group showed increased MD in right arcuate and left inferior fronto-occipital fasciculi compared with the TD group.

Our study revealed significant abnormal microstructural integrity of the white matter in the regions of several association and limbic pathways, as well as in corpus callosum in children with ASD and DD, suggesting that there may be a developmental dysregulation in the formation of neuronal networks in ASD and DD.

The findings in the present study could be used as imaging biomarkers for ASD and DD.

Jeong, J, Kumar, A, Sundaram, S, Chugani, H, Chugani, D, Aberrant White Matter Diffusion Property in Young Children with Autism Spectrum Disorder and Developmental Delay.  Radiological Society of North America 2010 Scientific Assembly and Annual Meeting, November 28 - December 3, 2010 ,Chicago IL. http://archive.rsna.org/2010/9011215.html