The utility of volumetric MRI in assessment of volume changes in ventral diencephalon in autistic children

Abstract Background Autism spectrum disorder (ASD) is a neurobehavioural disorder, characterized by abnormal affiliative and socio-emotional responses which are generally regulated by certain neuropeptides in the hypothalamus (an anatomic component of the ventral diencephalon (VD)). The use of volumetric MRI for studying VD volume change could provide a novel approach for identification of structural brain changes in ASD; this could assist in understanding the pathophysiology of ASD and would reflect on treatment strategies. The aim of the current work was to investigate the role of MRI volumetric analysis of the ventral diencephalon in young children diagnosed with autism spectrum disorder. Methods Fifty children diagnosed with ASD underwent volumetric brain analysis, on a fully automated MRI brain volumetry system (volBrain), with voxel-based morphometry of various segmental structures of the brain including the VD, using vol2Brain 1.0 pipeline software analysis suite. Results There were 48 out of 50 children who demonstrated abnormal VD volume which was found below the normal limits compared with reference standard normalized volume. All cases were normocephalic demonstrating normal intra-cranial cavity volumes. Forty out of fifty cases showed increased total volume of grey matter, and eighteen out of fifty cases showed increased total volume of white matter. Regarding the amygdala and hippocampus, there were only two cases (4.0%) which showed slightly increased relative volume of the total amygdala, and two other cases (4.0%) demonstrated increased relative volume of the total hippocampus. Comparison between the autistic patients and normal references revealed a significant difference regarding the VD volume and total volume of grey matter, whereas no significant differences were found regarding the white matter amygdala and hippocampus. Conclusions Based on the consistent significant volume decrease in the ventral diencephalon in patients with childhood autism, this study concluded that volumetric MRI analysis could be useful for diagnosis of childhood spectrum disorder and could be utilized as a reliable screening method in the clinically vague cases. Further study with a larger sample size including more age groups is recommended for more validation of the results.