Advanced Quantitative Microstructure Imaging in Autism: A Review of Methodology, Group Differences, and Associations...

Area of Science:

• Neuroimaging
• Developmental Neuroscience
• Autism Spectrum Disorder Research

Background:

• Autism spectrum disorder (ASD) is increasingly linked to alterations in white matter microstructure.
• Magnetic resonance imaging (MRI) advancements allow for detailed examination of these microstructural changes.

Purpose of the Study:

• To review advanced quantitative MRI techniques used in autism research.
• To summarize findings on group differences, developmental associations, and regional variations in white matter microstructure in autism.

Main Methods:

• Systematic review following PRISMA guidelines of 34 studies (2006-2024).
• Included diffusion MRI techniques (DKI, CSD), biophysical models (NODDI, WMTI), relaxometry, and magnetization transfer imaging (MTI).

Main Results:

• Constrained spherical deconvolution (CSD) and neurite orientation dispersion and density imaging (NODDI) were most common.
• Consistent reductions in CSD and NODDI measures were observed in major white matter regions.
• Findings from DKI, WMTI, and relaxometry showed variability.
• MRI measures correlated with cognitive, emotional, and social developmental outcomes.

Conclusions:

• Advanced MRI techniques provide valuable insights into white matter alterations in autism.
• CSD and NODDI show promise for consistent detection of microstructural differences.
• Further standardization of acquisition and processing methods is needed for robust findings.