Parameter comparison of white matter diffusion tensor imaging (DTI) in rhesus macaques (Macaca mulatta)

Area of Science:

• Neuroimaging
• Primate Neuroscience
• Biomedical Engineering

Background:

• Diffusion Tensor Imaging (DTI) is crucial for mapping white matter tracts.
• Optimizing DTI parameters is essential for accurate fiber tracking in non-human primates.
• Rhesus macaques are a key model organism in neuroscience research.

Purpose of the Study:

• To evaluate and compare four different DTI parameter settings for brain white matter analysis in rhesus macaques.
• To identify the optimal DTI sequence for accurate tracking of white matter fibers, including both coarse and fine tracts.

Main Methods:

• Analysis of DTI data from rhesus macaque brains using four distinct parameter sets (A, B, C, D).
• Parameters varied included b-value, spatial resolution, number of directions, and NSA.
• Evaluation of image quality, fractional anisotropy (FA) contrast, and fiber tracking accuracy for each sequence.

Main Results:

• Sequences A and B (b=1000/800 s/mm², 1.25mm³ resolution) accurately tracked coarse fibers.
• Sequence C (b=1000 s/mm², 0.55x0.55x2.5mm resolution) yielded fuzzy FA maps, unsuitable for fiber tracking.
• Sequence D (b=800 s/mm², 1.0mm³ resolution) provided high resolution and FA contrast, enabling tracking of both thick and thin fibers.

Conclusions:

• DTI parameter optimization is critical for successful white matter tractography in rhesus macaques.
• Sequence D represents an optimal DTI setting for rhesus macaque brain analysis due to its superior resolution and contrast.
• This optimized DTI protocol facilitates detailed investigation of white matter architecture in primate models.