fractional anisotropy; FA
Rare technical term used in medical imaging and materials science to quantify the directional dependence of diffusion.
In diffusion tensor imaging, fractional anisotropy is used to assess white matter.
異方性 means 'anisotropy' in general, while 異方性度 specifically refers to the quantitative measure 'fractional anisotropy'.
Compound of 異方性 (anisotropy) + 度 (degree), literally 'degree of anisotropy'. The term is a direct translation of the English 'fractional anisotropy'.