Abstract Archives of the RSNA, 2007


SSK13-03

Gray Matter Enlargement in Children with High Functioning Autism and Asperger Syndrome Using a Novel Method of Diffusion Based Morphometry

Scientific Papers

Presented on November 28, 2007
Presented as part of SSK13: Pediatric (Neuroradiology)

Participants

Manzar Ashtari PhD, Presenter: Nothing to Disclose
Joel Bregman MD, Abstract Co-Author: Nothing to Disclose
Shana Nichols, Abstract Co-Author: Nothing to Disclose
Carolyn McIlree MS, Abstract Co-Author: Nothing to Disclose
Lindat Spritzer BS, Abstract Co-Author: Nothing to Disclose
Andrew Adesman MD, Abstract Co-Author: Nothing to Disclose
Babak Ardekani PhD, Abstract Co-Author: Nothing to Disclose
et al, Abstract Co-Author: Nothing to Disclose
et al, Abstract Co-Author: Nothing to Disclose

PURPOSE

Neuroimaging findings in autism spectrum disorders (ASD) have been inconsistent in part due to differences in image analysis. Whereas most previous morphometric studies use segmentation techniques, apparent diffusion coefficient (ADC) based morphometry (ABM) is a powerful new technique that is not dependent on tissue segmentation, eliminating the risk for CNS tissue misclassification. In ABM, increase in cortical gray matter is accompanied by a corresponding decrease in the sulcal CSF resulting to an ADC decrease. Thus, ADC images may be used as a surrogate marker for regional gray matter volume change.

METHOD AND MATERIALS

Method: Subjects were recruited from the Fay J. Lindner Center for Autism. All met ADI-R & ADOS-G criteria for autistic or Asperger’s disorder. 14 ASD subjects and 12 age-, gender-, IQ-, SES-matched HC underwent diffusion MRI. A 15-direction isotropic diffusion sequence was obtained covering the whole brain. Following inter-subject registration of the ADC maps, two-tailed voxelwise t-test was applied.

RESULTS

ASD participants had enlarged GM volumes (decreased ADC) in the medial frontal gyri, left pre-central gyrus, right post-central gyrus, right fusiform/parahippocampal gyrus, bilateral temporal gyri and bilateral cerebellum (p<0.005 and a cluster size of 100 contiguous voxels). The ASD group had smaller GM volumes in the cerebellum and right amygdala. A separate two-tailed t-test showed no significant differences in the total brain volume of the autism participants as compared with HC.

CONCLUSION

ABM is a new, indirect method for highlighting brain regions with potential GM volume changes using diffusion-weighted MR. We found GM changes consistent with recent volumetric or voxel based morphometry reports. These areas have been linked to deficits in social-cognitive processes in autism. We believe that ABM is extremely valuable for understanding and exploring brain abnormalities in autism and related disorders

CLINICAL RELEVANCE/APPLICATION

We believe that ADC based morphometry ABM is a superior method over the voxel based morphometry as and is extremely valuable for understanding and exploring brain abnormalities in autism and related disorders.

Cite This Abstract

Ashtari, M, Bregman, J, Nichols, S, McIlree, C, Spritzer, L, Adesman, A, Ardekani, B, et al, , et al, , Gray Matter Enlargement in Children with High Functioning Autism and Asperger Syndrome Using a Novel Method of Diffusion Based Morphometry.  Radiological Society of North America 2007 Scientific Assembly and Annual Meeting, November 25 - November 30, 2007 ,Chicago IL. http://archive.rsna.org/2007/5012148.html