Neurobiological origin of spurious brain morphological changes: A quantitative MRI study

Area of Science:

• Neuroimaging
• Computational Anatomy
• Quantitative MRI

Background:

• T1-weighted MRI is standard for brain morphology analysis due to high contrast and resolution.
• Image intensity in T1-weighted MRI is influenced by T1, R2*, and proton density (PD), reflecting histological properties.
• The mixed contribution of these parameters complicates neurobiological interpretation of morphometry findings.

Purpose of the Study:

• To investigate the impact of different MRI parameters on brain morphometry measures.
• To assess how microstructural properties (myelination, iron, water content) affect automated brain morphology analysis.
• To evaluate the influence of age on these variations.

Main Methods:

• Acquired quantitative R1, R2*, and PD maps from 120 healthy subjects (aged 18-87).
• Generated synthetic T1-weighted MRI images from quantitative maps.
• Extracted morphometry features (gray matter volume, cortical thickness) from synthetic images.

Main Results:

• Significant variations in morphometry measures were observed based on different combinations of MRI parameters.
• Age modulated these variations, indicating age-related microstructural changes influence results.
• Microstructural properties significantly impact automated brain morphology measures.

Conclusions:

• Microstructural tissue properties (myelination, iron, water) affect automated brain morphology measures.
• Standard T1-weighted MRI may lead to spurious findings in computational anatomy.
• Quantitative MRI data are valuable for inferring microscopic tissue changes in brain studies.