Accuracy of the measurement of diffusion anisotropy of the brain; comparison between analysis by diffusion tensor imaging and that by three-orthogonal diffusion-weighted imaging

We compared the index for diffusion anisotropy obtained from diffusion tensor analysis (Fractional Anisotropy; FA) with that from 3-orthogonal diffusion-weighted imaging (FA-3). In the white matter of healthy subjects, FA-3 was significantly more asymmetric than FA. In one case with a brain tumor compressing the pyramidal tract, FA-3 showed markedly underestimated, which led erroneous conclusion. The tensor analysis should be necessary for evaluation of diffusion anisotropy.