Dissociation of tau deposits and brain atrophy in early Alzheimer's disease: A combined positron emission Tomography/Magnetic resonance imaging study

Yoko Shigemoto, Daichi Sone, Etsuko Imabayashi, Norihide Maikusa, Nobuyuki Okamura, Shozo Furumoto, Yukitsuka Kudo, Masayo Ogawa, Harumasa Takano, Yuma Yokoi, Masuhiro Sakata, Tadashi Tsukamoto, Koichi Kato, Noriko Sato, Hiroshi Matsuda

Research output: Contribution to journalArticlepeer-review

6 Citations (Scopus)

Abstract

The recent advent of tau-specific positron emission tomography (PET) has enabled in vivo assessment of tau pathology in Alzheimer's disease (AD). However, because PET scanners have limited spatial resolution, the measured signals of small brain structures or atrophied areas are underestimated by partial volume effects (PVEs). The aim of this study was to determine whether partial volume correction (PVC) improves the precision of measures of tau deposits in early AD. We investigated tau deposits in 18 patients with amyloid-positive early AD and in 36 amyloid-negative healthy controls using 18F-THK5351 PET. For PVC, we applied the SPM toolbox PETPVE12. The PET images were then spatially normalized and subjected to voxel-based group analysis using SPM12 for comparison between the early AD patients and healthy controls. We also compared these two groups in terms of brain atrophy using voxel-based morphometry of MRI. We found widespread neocortical tracer retention predominantly in the posterior cingulate and precuneus areas, but also in the inferior temporal lobes, inferior parietal lobes, frontal lobes, and occipital lobes in the AD patients compared with the controls. The pattern of tracer retention was similar between before and after PVC, suggesting that PVC had little effect on the precision of tau load measures. Gray matter atrophy was detected in the medial/lateral temporal lobes and basal frontal lobes in the AD patients. Interestingly, only a few associations were found between atrophy and tau deposits, even after PVC. In conclusion, PVC did not significantly affect 18F-THK5351 PET measures of tau deposits. This discrepancy between tau deposits and atrophy suggests that tau load precedes atrophy.

Original languageEnglish
Article number223
JournalFrontiers in Aging Neuroscience
Volume10
Issue numberJUL
DOIs
Publication statusPublished - 2018 Jul 18

Keywords

  • Alzheimer's disease
  • Brain atrophy
  • Magnetic resonance imaging
  • Partial volume correction
  • Positron emission tomography
  • Tau

ASJC Scopus subject areas

  • Ageing
  • Cognitive Neuroscience

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