fixel
Voxel subdivision representing a specific fiber population with unique orientation, used in advanced diffusion MRI analysis.
Full Definition
A fixel (fiber element) is a computational unit that represents a specific fiber population within a voxel, characterized by a particular orientation and set of diffusion properties. Unlike traditional voxel-based analysis that assumes a single fiber orientation per voxel, fixel-based analysis acknowledges that multiple fiber populations can exist within the same voxel. This approach enables more precise analysis of complex white matter architecture, particularly in regions with crossing, kissing, or fanning fibers.
Usage
Usage note: Coined term combining 'fiber' and 'voxel'; maintain consistent usage in advanced diffusion imaging contexts.
In Context
- "Fixel-based analysis revealed specific white matter changes in crossing fiber regions." — Diffusion MRI research paper
- "Each fixel represents a distinct fiber population with its own diffusion characteristics." — Advanced DTI methodology