Objectives: Autism Spectrum Disorder (ASD) is regarded as an early onset behavioural syndrome but no biological markers have been established yet. Functional studies have shown localized focal hypoperfusion and abnormalities in the anatomo-functional connectivity of the limbic-striatal social brain. The aim of this study was to investigate the regional cerebral blood flow (rCBF) at rest in subjects with ASD as compared to a group of healthy controls.
Methods: Thirteen normal intelligence patients with ASD and ten healthy controls (HC) underwent PET/CT using [1-11C]-butanol, a perfusion tracer produced from [11C]carbon dioxide. The whole examination time was less than 10 minutes. Data were analysed by SPM (p=0.05 for voxel height, pcorrected<0.001 at cluster level and puncorrected < 0.001 at voxel level).
Results: As compared to HC, ASD showed a highly significant CBF increase in right parahippocampal (BAs 28, 30,35), limbic (BAs13, 23), visual (BAs 17, 18, 19) and temporal cortex (BAs 21, 37, 38, 39), putamen, caudatus and cerebellum.
Conclusions: Using state-of-the-art neuroimaging methodologies, reduced considerably the examination time resulting in less stress to these psychiatric patients and in robust results. The limbic and posterior associative cortices and cerebellum were found to have an increased CBF in ASD, underscoring their involvement in the disease and raising methodological and diagnostic issues to be considered when exploring the neuroanatomy of ASD.