Mean Apparent Propagator MRI: A Potential Imaging Biomarker of Brain Microstructural Alterations in Basic-Type...

Area of Science:

• Neuroimaging
• Ophthalmology
• Pediatric Neurology

Background:

• Intermittent exotropia (IXT) is a common childhood strabismus affecting binocular vision and oculomotor control.
• Understanding the underlying brain alterations in IXT is crucial for developing effective diagnostic and therapeutic strategies.

Purpose of the Study:

• To investigate brain microstructural alterations in children with basic-type IXT using mean apparent propagator magnetic resonance imaging (MAP-MRI).
• To analyze the correlations between MAP-MRI metrics and clinical signs of IXT.

Main Methods:

• MRI scans (3T Siemens) including 3D T1-weighted and diffusion-weighted images were acquired from 78 children with basic-type IXT and 96 healthy controls.
• MAP-MRI parametric maps were reconstructed, and voxel-wise analysis and fiber tractography were performed to assess microstructural changes in cortical regions and the visual pathway.
• Receiver operating characteristic (ROC) analysis was used to evaluate the discriminative performance of MAP-MRI metrics.

Main Results:

• MAP-MRI identified extensive microstructural alterations in brain regions related to binocular vision, oculomotor control, cognition, and emotion regulation in children with IXT (P < 0.01).
• MAP-MRI metrics demonstrated excellent discriminative performance (AUC = 0.986) in differentiating IXT from controls.
• Significant correlations were found between MAP-MRI metrics and IXT disease severity and duration (P < 0.05).

Conclusions:

• MAP-MRI effectively detects widespread microstructural brain changes associated with IXT in children.
• These findings provide insights into the neural underpinnings of impaired binocular vision and oculomotor control in IXT.
• MAP-MRI metrics show potential as noninvasive imaging biomarkers for IXT-related microstructural alterations.