Brain Imaging and Behavior

, Volume 6, Issue 3, pp 426–436

Local susceptibility causes diffusion alterations in patients with Alzheimer’s disease and mild cognitive impairment

Article

DOI: 10.1007/s11682-012-9155-6

Cite this article as:
Jahng, GH. & Xu, S. Brain Imaging and Behavior (2012) 6: 426. doi:10.1007/s11682-012-9155-6

Abstract

Recent studies with positron emission tomography (PET) using the Pittsburgh compound B (PIB) found widespread amyloid plaque depositions in patients with Alzheimer’s disease (AD) and mild cognitive impairment (MCI) and even in cognitively normal (CN) subjects. The aim of this study was to investigate whether the local susceptibility gradients in brain tissue alter regional diffusion measurements using MRI in patients with AD and MCI. Two diffusion tensor (DT)-MRI data sets were acquired with alternating polarities of the external diffusion-sensitizing gradients. Three subject groups were included: 15 patients with AD, 18 patients with MCI and 16 CN. Maps of mean diffusivity (MD) and fractional anisotropy (FA) were computed separately for positive (p) and negative (n) polarities (pMD and nMD, pFA and nFA). Voxel-wise paired t-tests were performed between pMD versus nMD or between pFA versus nFA maps, separately for each subject group. We also investigated regions-of-interest (ROIs) in the brain. Based on the pair-wise comparisons, we found significant differences between pMD and nMD in all three groups. Results of ROI-based analyses showed that the non-linear behaviors of the ROI data sets were shown for all three groups. In conclusion, significant differences of MD maps between the two polarities of diffusion-sensitizing gradients were found, suggesting that the intrinsic background gradients may alter MD signals in specific regions. It can be important to take into account the effects of local gradient alterations during diffusion measurements in patients with AD, MCI and elderly controls.

Keywords

Local susceptibility gradients Diffusion tensor imaging Two polarities of diffusion gradients Alzheimer’s disease Mild cognitive impairment 

Copyright information

© Springer Science+Business Media, LLC 2012

Authors and Affiliations

  1. 1.Department of Radiology, Kyung Hee University Hospital at GangdongSchool of Medicine of Kyung Hee UniversitySeoulSouth Korea
  2. 2.Department of Biomedical ScienceGraduate School of Kyung Hee UniversitySeoulSouth Korea

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