title: Diffusion tensor studies and voxel-based morphometry of the temporal lobe to determine the cognitive prognosis in cases of Alzheimer's disease and mild cognitive impairment: Do white matter changes precede gray matter changes?
abstract: OBJECTIVE
  The purpose of the current study was to assess the feasibility of diffusion tensor imaging (DTI) parameters for determining the prognosis of Alzheimer's disease (AD). We also analyzed the correlation among DTI, voxel-based morphometry (VBM), and results of the mini-mental state examination (MMSE).
  
  
  METHODS
  The subjects of this prospective study were patients with AD and mild cognitive impairment. We performed annual follow-ups with DTI, VBM, and MMSE for 2 or 3 years. On DTI, the apparent diffusion coefficient (ADC) and fractional anisotropy (FA) of the uncinate fascicles were measured. VBM was performed to provide a z-score for the parahippocampal gyrus. The correlations among these factors were evaluated in the same period and the next period of the follow-up study.
  
  
  RESULTS
  For evaluation of the same period, both DTI parameters and z-scores showed statistically significant correlations with the MMSE score. Also for evaluation of the next period, both DTI parameters and z-scores showed statistically significant correlations with the MMSE score of the next period. We observed a statistically significant correlation between the ADC value of the uncinate fascicles and the z-score of the next period.
  
  
  CONCLUSIONS
  Diffusion tensor parameters (ADC and FA) of the uncinate fascicles correlated well with cognitive function in the next year and seemed to be feasible for use as biomarkers for predicting the progression of AD. In addition, the white matter changes observed in the ADC seemed to precede changes in the gray matter volume of the parahippocampal gyrus that were represented by z-scores of VBM.
authors.affiliation: Department of Radiology, Nagoya University Hospital, 65 Tsurumai-cho, Showa-ku, Nagoya, Aichi 466-8550 Japan.
authors.forename: Toshiaki
authors.initials: T
authors.lastname: Taoka
authors.affiliation: Department of Psychiatry, Nara Medical University, 840 Shijo-cho, Kashihara, Nara 634-8522 Japan.
authors.forename: Fumihiko
authors.initials: F
authors.lastname: Yasuno
authors.affiliation: Department of Psychiatry, Nara Medical University, 840 Shijo-cho, Kashihara, Nara 634-8522 Japan.
authors.forename: Masayuki
authors.initials: M
authors.lastname: Morikawa
authors.affiliation: Department of Psychiatry, Nara Medical University, 840 Shijo-cho, Kashihara, Nara 634-8522 Japan.
authors.forename: Makoto
authors.initials: M
authors.lastname: Inoue
authors.affiliation: Department of Psychiatry, Nara Medical University, 840 Shijo-cho, Kashihara, Nara 634-8522 Japan.
authors.forename: Kuniaki
authors.initials: K
authors.lastname: Kiuchi
authors.affiliation: Department of Psychiatry, Nara Medical University, 840 Shijo-cho, Kashihara, Nara 634-8522 Japan.
authors.forename: Soichiro
authors.initials: S
authors.lastname: Kitamura
authors.affiliation: Department of Psychiatry, Nara Medical University, 840 Shijo-cho, Kashihara, Nara 634-8522 Japan.
authors.forename: Kiwamu
authors.initials: K
authors.lastname: Matsuoka
authors.affiliation: Department of Psychiatry, Nara Medical University, 840 Shijo-cho, Kashihara, Nara 634-8522 Japan.
authors.forename: Toshifumi
authors.initials: T
authors.lastname: Kishimoto
authors.affiliation: Department of Radiology, Nara Medical University, 840 Shijo-cho, Kashihara, Nara 634-8522 Japan.
authors.forename: Kimihiko
authors.initials: K
authors.lastname: Kichikawa
authors.affiliation: Department of Radiology, Nagoya University Hospital, 65 Tsurumai-cho, Showa-ku, Nagoya, Aichi 466-8550 Japan.
authors.forename: Shinji
authors.initials: S
authors.lastname: Naganawa
keywords: Alzheimer’s disease; Biomarker; Diffusion tensor image; Prognosis; Voxel-based morphometry