Understanding the Physiopathology Behind Axial and Radial Diffusivity Changes-What Do We Know?

Area of Science:

• Neuroimaging
• Biomedical Engineering
• Radiology

Background:

• Diffusion Tensor Imaging (DTI) is increasingly used in neuroimaging.
• Quantitative validation of DTI metrics is limited due to challenges in co-registering histology with MRI.
• Understanding white matter structure is crucial for interpreting DTI findings.

Purpose of the Study:

• To review the current knowledge on axial (λ_║) and radial (λ_┴) diffusivity as DTI markers.
• To summarize DTI's potential for detecting axonal and myelin damage.
• To discuss challenges and future directions in DTI research.

Main Methods:

• Review of seminal studies on axial (λ_║) and radial (λ_┴) diffusivity.
• Discussion of DTI technical background and white matter organization.
• Analysis of DTI interpretation in clinical conditions with inflammation and edema.

Main Results:

• Axial (λ_║) and radial (λ_┴) diffusivity show potential as in vivo markers for axonal and myelin damage.
• Consistent information is observed in healthy subjects and conditions with minimal edema/inflammation.
• DTI provides valuable information on white matter tracts and disconnection mechanisms.

Conclusions:

• DTI is a promising non-invasive tool for medical diagnostics.
• Axial (λ_║) and radial (λ_┴) diffusivity offer consistent insights into white matter integrity.
• Further research is needed to overcome challenges in DTI interpretation for complex pathologies.