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Updated: May 31, 2026
Probing the Brain in Autism Using fMRI and Diffusion Tensor Imaging
Published on: September 12, 2011
Regional cerebral blood flow in children with autism spectrum disorders: a quantitative ⁹⁹mTc-ECD brain SPECT study
Wen-Han Yang1, Jin Jing, Li-Juan Xiu
1Faculty of Child and Maternal Health, School of Public Health, Sun Yat-sen University, Guangzhou, Guangdong 510080, China.
Insights
This study found reduced regional cerebral blood flow (rCBF) in children with autism spectrum disorders (ASD), particularly in the frontal lobe and basal ganglia. Asperger syndrome (AS) showed distinct patterns, suggesting different neurobiological underpinnings in ASD.
Area of Science:
- Neuroscience
- Pediatrics
- Radiology
Background:
- Autism spectrum disorders (ASD) encompass autism, Asperger syndrome (AS), and PDD-NOS, characterized by social deficits and repetitive behaviors.
- Regional cerebral blood flow (rCBF) measured by SPECT is a key indicator of brain activity.
- Previous SPECT studies on rCBF in ASD have yielded inconsistent results, with limited focus on non-autistic subtypes.
Purpose of the Study:
- To investigate alterations in rCBF in children diagnosed with ASD using SPECT.
- To compare rCBF patterns between autistic children and those with Asperger syndrome (AS).
Main Methods:
- Brain SPECT imaging was conducted on 23 children with ASD (mean age 7.2 years) and 8 age-matched controls (mean age 5.5 years).
- Image analysis utilized Statistical Parametric Mapping (SPM5) and Student's t-tests to compare rCBF and hemispheric asymmetry.
- Covariance analysis was performed, controlling for age differences between groups.
Main Results:
- Significant rCBF reduction was observed in the bilateral frontal lobe and basal ganglia in the autism group compared to controls.
- Children with AS showed reduced rCBF in frontal, temporal, parietal lobes, and cerebellum.
- Asymmetry of hemispheric hypoperfusion was noted in the ASD group, more pronounced in AS.
Conclusions:
- Reduced rCBF in ASD appears to be a global phenomenon affecting frontal, temporal, limbic, and basal ganglia regions.
- Hemispheric hypoperfusion asymmetry in AS suggests distinct neurobiological mechanisms compared to autism.
- SPECT imaging can reveal differential patterns of cerebral blood flow in ASD subtypes.
Background:
Autism spectrum disorders (ASD), which include autism, asperger syndrome (AS) and pervasive developmental disorder-not otherwise specified (PDD-NOS), are devastating neurodevelopmental disorders of childhood resulting in deficits in social interaction, repetitive patterns of behaviors, and restricted interests and activities. Single photon emission computed tomography (SPECT) is a common technique used to measure regional cerebral blood flow (rCBF). Several studies have measured rCBF in children with ASD using SPECT, however, findings are discordant. In addition, the majority of subjects used in these studies were autistic. In this study, we aimed to investigate changes in rCBF in children with ASD using SPECT.
Methods:
A Technetium-99m-ethyl cysteinate dimmer (⁹⁹m)Tc-ECD) brain SPECT study was performed on an ASD group consisting of 23 children (3 girls and 20 boys; mean age (7.2 ± 3.0) years) who were diagnosed according to Diagnostic and Statistical Manual of Mental Disorders, 4th edition (DSM-IV) criteria and an age-matched control group with 8 children (1 girl and 7 boys, mean age (5.5 ± 2.4) years). Image data were evaluated with Statistical Parametric Mapping, 5th version (SPM5). A Student's t test for unpaired data was used to compare rCBF and asymmetry in the autism and corresponding control group. The covariance analysis, taking age as covariance, was performed between the ASD and control group.
Results:
There was a significant reduction in rCBF in the bilateral frontal lobe (frontal poles, arcula frontal gyrus) and the bilateral basal ganglia in the autism group, and a reduction in the bilateral frontal, temporal, parietal, legumina nucleus and cerebellum in the AS group compared to the control. In addition, asymmetry of hemispheric hypoperfusion in the ASD group was observed. Inner-group comparison analysis revealed that rCBF decreased significantly in the bilateral frontal lobe (42.7%), basal nucleus (24.9%) and temporal lobe (22.8%) in the autism group, and in the bilateral cerebellum (22.8%), basal nucleus (19.3%) and right thalamencephalon (16.6%) in the AS group (P < 0.05).
Conclusions:
The decrease in rCBF in ASD is a global event, which involves the bilateral frontal, temporal, limbic system and basal ganglias. Asymmetry of hemispheric hypoperfusion was more obvious in the AS group than the autism group, which indicates a different neurobiological mechanism from that of autism.
