Selection of Appropriate Fractional Anisotropy (FA) Threshold for Tract Based Diffusion Tensor Analysis of Uncinate Fascicles in Alzheimer Disease.

Toshiaki Taoka¹, Toshiaki Akashi¹, Toshiteru Miyasaka¹, Hiroyuki Nakagawa¹, Kaoru Myochin¹, Satoru Iwasaki², Kimihiko Kichikawa¹

Tract based analysis of white matter tract is a useful method to analyze pathological change in selected tract and fractional anisotropy (FA) threshold is set when drawing tractography and has influence in drawn tractography. This FA threshold had influence for measured value of FA and ADC along the tract. For tract based analysis of degenerative disease, appropriate selection of FA threshold to draw tractography is important for effective and meaningful evaluation. In the case with analysis of uncinate fasciculus in AD, FA threshold of 0.15 and 0.2 showed better discrimination among different severity of AD both for FA and ADC.