Diffusion-Weighted Imaging: Recent Advances and Applications.

Area of Science:

• Neuroimaging
• Biophysics
• Medical Physics

Background:

• Quantitative diffusion imaging characterizes human brain microstructure in vivo.
• Widely used in neuroscientific and clinical research.
• Standard diffusion tensor imaging (DTI) detects microstructural changes and anisotropy.

Purpose of the Study:

• Review basic physical principles and current diffusion imaging techniques.
• Overview of standard and advanced diffusion MRI methods and their clinical applications.
• Discuss challenges, limitations, and future directions in diffusion imaging.

Main Methods:

• Explains principles of diffusion imaging.
• Reviews standard diffusion tensor imaging (DTI).
• Details advanced techniques like high-angular resolution diffusion imaging (HARDI) and biophysical models (e.g., NODDI).

Main Results:

• DTI characterizes microstructure and anisotropy but struggles with complex fiber topologies.
• Advanced techniques like HARDI and biophysical models capture complex intravoxel topologies.
• Biophysical models enable computation of voxel-wise maps of axonal density/morphology as potential biomarkers.

Conclusions:

• Advanced diffusion MRI techniques and biophysical models offer enhanced specificity for brain microstructure.
• These methods hold promise as clinically viable biomarkers for neurological and neuroscientific applications.
• Novel diffusion encoding approaches may further improve specificity for intra-voxel diffusion heterogeneity.