In Vivo Measurement of Rat Brain Water Content at 9.4 T MR Using Super-Resolution Reconstruction: Validation With Ex...

Area of Science:

• Neuroimaging
• Biophysics
• Medical Physics

Background:

• Brain water content changes are linked to neurologic diseases.
• Non-invasive in vivo investigation of water content is crucial for understanding disease pathogenesis.
• Developing advanced imaging techniques can improve diagnostic capabilities.

Purpose of the Study:

• To adapt a human super-resolution (SRR) technique for rat brain in vivo high-resolution (HR) water content mapping.
• To compare in vivo MRI-based water content with ex vivo wet/dry measurements.
• To validate a novel non-invasive method for quantitative brain analysis.

Main Methods:

• A 9.4-T MRI scanner with a multi-echo gradient-echo (mGRE) sequence was used.
• Super-resolution reconstruction (SRR) created HR isotropic (200 µm) water content maps from low-resolution (LR) images.
• Ex vivo wet/dry measurements served as the reference standard for validation.

Main Results:

• In vivo MRI-derived water content strongly correlated with ex vivo measurements (r=0.902) at the regional level.
• Significantly different water content values were observed across distinct brain regions.
• Frontal brain regions exhibited the highest water content, followed by the midbrain, and cerebellum/brainstem regions showed the lowest.

Conclusions:

• The adapted SRR technique successfully generated high-resolution isotropic water content maps in vivo in the rat brain.
• The MRI-derived water content values demonstrated strong agreement with ex vivo reference standards.
• This non-invasive method holds promise for studying water content alterations in neurologic diseases.