Multi-delay arterial spin labeling brain magnetic resonance imaging study for pediatric autism

Arterial spin labeling (ASL) is a non-invasive magnetic resonance imaging (MRI) technique that can measure regional cerebral blood flow (rCBF) without radiation exposure. This study aimed to evaluate rCBF in individuals with autism and their age-matched controls, globally and regionally.

We performed ASL MRI (3 T, pulsed-continuous ASL, 3 delayed ASL imaging sequences) for 33 patients with autism spectrum disorder (ASD) (average age: 7.3 years, range: 2-14 years). Nineteen children (average age: 8.6 years, range: 3-15 years) without ASD and intellectual delay were included as controls. Patients with morphological abnormalities detected on MRI were excluded. Objective analysis was performed with automatic region of interest analysis of the ASL results. The Mann-Whitney U test was used to compare the rCBF results between the groups.

Compared to the controls, patients with ASD showed a statistically significant decrease in rCBF, respectively, in the insula [left, rCBF 51.8 ± 9.5 mL/100 g/min (mean ± SD) versus 59.9 ± 9.8, p = 0.0017; right, 51.2 ± 10.1 versus 57.8 ± 8.8, p = 0.0354], superior parietal lobule (left, 44.6 ± 8.4 versus 52.0 ± 7.8, p = 0.003), superior temporal gyrus (left, 50.0 ± 8.6 versus 56.9 ± 8.6, p = 0.007; right, 49.5 ± 8.4 versus 56.4 ± 7.7, p = 0.0058), and inferior frontal gyrus (left, 53.0 ± 9.8 versus 59.3 ± 9.9, p = 0.0279), which are associated with the mirror neuron system.

We concluded that patients with ASD showed a statistically significant decline in CBF in regions associated with the mirror neuron system. The advantages of ASL MRI include low invasiveness (no radiation exposure) and short imaging time (approximately 5 min). Studies with larger sample sizes are required to establish the diagnostic value of ASL MRI for ASD.