Investigation of resolution effects using a specialized diffusion tensor phantom.

Area of Science:

• Neuroimaging
• Diffusion Tensor Imaging (DTI)
• Biomedical Engineering

Background:

• Diffusion imaging is vital for analyzing brain structures like the fornix and cingulum, implicated in psychiatric disorders.
• Quantifying diffusion parameters in fine brain structures is challenging due to partial volume effects (PVEs).

Purpose of the Study:

• To present a novel phantom for investigating PVEs in diffusion imaging of fine brain structures.
• To assess the influence of PVEs on diffusion parameter quantification.

Main Methods:

• A phantom was created using polyester fibers with defined square cross-sections (1-25 mm²).
• The phantom provides homogeneous, high fractional anisotropy (FA ≈ 0.9) for controlled PVE analysis.
• PVEs and their impact on diffusion parameters and fiber geometry were analyzed.

Main Results:

• Inferred diffusion parameters and fiber geometry are highly sensitive to the structure's position within the voxel grid.
• PVEs significantly impact post-processing methods like Tract-based Spatial Statistics and fiber tractography.
• The study demonstrates the problematic nature of handling PVEs in standard post-processing tasks.

Conclusions:

• The developed phantom is a valuable tool for evaluating and mitigating PVEs in diffusion imaging.
• Improved handling of PVEs is essential for accurate diffusion parameter quantification in fine brain structures.
• This research aids in advancing neuroimaging analysis for psychiatric disease research.