anisotropy

Full Definition

Anisotropy describes the directional dependence of water molecule diffusion within brain tissue, particularly evident in organized structures such as white matter fiber tracts. In healthy white matter, water molecules diffuse more freely along axonal fibers than perpendicular to them, creating measurable anisotropy. Diffusion tensor imaging quantifies this property through metrics like fractional anisotropy, which serves as a biomarker for white matter integrity and microstructural organization.

Usage

Usage note: Distinguish from fractional anisotropy, which is a specific quantitative measure derived from anisotropy.

In Context

• "Reduced anisotropy in the corpus callosum suggested axonal degeneration." — DTI analysis report
• "White matter anisotropy decreases with normal aging processes." — Research findings