Multicenter Tract-Based Analysis of Microstructural Lesions within the Alzheimer's Disease Spectrum: Association with

Stefan J Teipel1,2, Jan O Kuper-Smith1, Claudia Bartels3,4

  • 1Department of Psychosomatic Medicine, University of Rostock, Rostock, Germany.

Insights

Diffusion tensor imaging (DTI) detects microstructural changes in mild cognitive impairment (MCI) and Alzheimer's disease (AD). DTI shows promise as a biomarker for MCI but not for earlier preclinical AD stages like subjective cognitive decline.

Area of Science:

  • Neuroimaging
  • Neurology
  • Biomarker Discovery

Background:

  • Diffusion tensor imaging (DTI) detects microstructural lesions in mild cognitive impairment (MCI), prodromal Alzheimer's disease (AD), and AD dementia.
  • Subjective cognitive decline (SCD) represents a potential pre-MCI stage of AD.
  • Investigating DTI's utility in identifying early AD-related brain changes is crucial.

Purpose of the Study:

  • To evaluate DTI's effectiveness in detecting white matter alterations across the Alzheimer's disease spectrum, from subjective cognitive decline to AD dementia.
  • To assess the diagnostic accuracy of DTI parameters for identifying MCI and discriminating between Aβ-positive and Aβ-negative individuals.
  • To determine if DTI can serve as a reliable biomarker for preclinical AD stages.

Main Methods:

  • Analysis of DTI parameters in a cohort of 271 participants (93 controls, 98 SCD, 45 MCI, 35 AD dementia) from the DELCODE study.
  • Tract-based spatial statistics were used to compare white matter integrity across diagnostic groups.
  • Cross-validated diagnostic accuracy was calculated for DTI parameters in distinguishing clinical groups and Aβ-positive status.

Main Results:

  • Reductions in fiber tract integrity were observed in MCI and AD dementia compared to controls.
  • Subjective cognitive decline (SCD) participants showed limited white matter alterations, primarily at uncorrected significance levels.
  • DTI achieved nearly 80% diagnostic accuracy for MCI and discriminating Aβ-positive MCI, but random accuracy for preclinical AD (Aβ-positive SCD).

Conclusions:

  • Multicenter DTI with harmonized acquisition shows potential as a useful biomarker for prodromal AD (Aβ-positive MCI).
  • Automated tract-based DTI analysis is not currently effective for identifying preclinical AD, including Aβ-positive SCD.
  • Further research is needed to refine DTI applications for early Alzheimer's disease detection.

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