Evaluation of Fibers in Limbic Circuits by Tract-Specific Diffusion Tensor Analysis. -Accessing Severity of Alzheimer Disease.

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

The purpose of this study is to evaluate changes in fibers of limbic circuit using tract-based diffusion tensor analysis as an indicator of severity of Alzheimer disease (AD) and mild cognitive impairment (MCI). Increased diffusivity and decreased diffusion anisotropy in limbic circuits correlated to the severity of AD and MCI. Degeneration of white matter fiber tracts secondary to neuronal loss in the associative cortex may be one of the reasons of these AD associated changes in limbic circuits. Decreased FA and increased ADC may be useful as a marker for severity of AD.