就学前自閉スペクトラム症における脳微細構造の変化の評価：ボクセルごとのマルチモーダルMRI研究

Autism Spectrum Disorder (ASD) presents with early neurodevelopmental alterations in preschool children, yet comprehensive characterization using multimodal quantitative MRI remains limited in this age group.

To investigate voxel-wise brain microstructural differences in preschool ASD through integrated analysis of cerebral perfusion, multiparametric relaxometry, and magnetic susceptibility.

Prospective case-control.

Twenty nine-children with ASD (age 2-6 years; 23 males/6 females) and 25 age-/sex-matched healthy controls (HC).

3.0 T MRI; high-resolution 3D-T1WI, quantitative susceptibility mapping (QSM), synthetic MRI (SyMRI), 3D pseudo-continuous arterial spin labeling (3D-pCASL).

Clinical assessments included the Gesell Developmental Schedules (GDS) and Childhood Autism Rating Scale (CARS). Imaging analysis consisted of voxel-wise whole-brain assessment of QSM, T1/T2/PD, and cerebral blood flow (CBF) maps.

General linear models with cluster-based thresholding were applied for group comparison; Spearman's rank correlation with Bonferroni correction was used for clinical associations; and receiver operating characteristic (ROC) analysis with Delong's test was performed to compare diagnostic performance based on the areas under the curve (AUCs).

Compared to HC, children with ASD showed decreased QSM values in the left superior/middle frontal gyri (SFG/MFG; cluster = 212 voxels, peak T = 5.55, p < 0.001). They also had reduced T1 relaxation times in bilateral SFG/MFG/precentral/postcentral gyri (four clusters: 315-750 voxels, peak T = 5.11-5.88, all p < 0.001). QSM values in the left SFG/MFG correlated positively with fine motor scores (r = 0.630, p < 0.001), while T1 values in the bilateral precentral/postcentral gyri correlated with gross motor scores (right: r = 0.548, p = 0.002; left: r = 0.461, p = 0.012). ROC analysis showed high diagnostic accuracy for both QSM (left SFG/MFG AUC = 0.858) and T1 values (left SFG/MFG AUC = 0.905; bilateral precentral/postcentral gyri AUC = 0.892-0.908).

Preschool ASD demonstrates prefrontal iron deficiency (reduced QSM) and sensorimotor myelination alterations (decreased T1), which correlate with motor deficits and show high diagnostic efficacy.

2.

Stage 2.