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Saturday, May 9, 2009
Northwest Hall (Chicago Hilton)
10:00 AM
Background: The tissue nature of brain enlargement in young autistic subjects has not yet been clearly established. Published findings do not support an increase in neuronal density in gray matter or the attribution of white matter enlargement to an increase in myelinated fibers. Given the growing documentation of metabolic findings in autism, these brain changes need to be investigated using techniques sensitive to metabolites. Frontal and prefrontal white matter enlargement is particularly prominent and its metabolic underpinnings need to be targeted using magnetic resonance spectroscopy (MRS) methods. Objectives: To investigate metabolic alterations in ASD brain tissue collected using single voxel spectroscopy and chemical shift imaging.
Methods: Proton magnetic resonance spectroscopy was performed with a 3T Siemens scanner on age matched typically developing and children with Autism Spectrum Disorders (6-13 year olds). Single Voxel Spectroscopy (SVS) was acquired with the voxel placed on the left prefrontal white matter; Chemical Shift Imaging (CSI) was acquired with the grid placed centrally covering prefrontal white matter as well as over portions of corpus callosum, parietal gray matter, prefrontal grey matter, caudate, thalamus, and parietal gray matter regions. The spectra were processed offline using LCModel, a user independent fitting routine.
Results: We will present our findings where significant differences were observed (p<0.05) and where no significant differences were observed (p>0.05) in ratios and absolute concentrations of N-Acetylaspartate, choline, myo-Inositol , glutamine/glutamate , creatine and lactate in the investigated regions.
Conclusions: The identification of metabolic alterations by MRI in ASD helps characterize the tissue dimension of brain alterations in this complex condition and to sharpen hypotheses regarding linkages between tissue pathophysiology and cognitive neuroscience.
Methods: Proton magnetic resonance spectroscopy was performed with a 3T Siemens scanner on age matched typically developing and children with Autism Spectrum Disorders (6-13 year olds). Single Voxel Spectroscopy (SVS) was acquired with the voxel placed on the left prefrontal white matter; Chemical Shift Imaging (CSI) was acquired with the grid placed centrally covering prefrontal white matter as well as over portions of corpus callosum, parietal gray matter, prefrontal grey matter, caudate, thalamus, and parietal gray matter regions. The spectra were processed offline using LCModel, a user independent fitting routine.
Results: We will present our findings where significant differences were observed (p<0.05) and where no significant differences were observed (p>0.05) in ratios and absolute concentrations of N-Acetylaspartate, choline, myo-Inositol , glutamine/glutamate , creatine and lactate in the investigated regions.
Conclusions: The identification of metabolic alterations by MRI in ASD helps characterize the tissue dimension of brain alterations in this complex condition and to sharpen hypotheses regarding linkages between tissue pathophysiology and cognitive neuroscience.