Reduced blood oxygenation level dependent connectivity is related to hypoperfusion in Alzheimer's disease

J Cereb Blood Flow Metab. 2019 Jul;39(7):1314-1325. doi: 10.1177/0271678X18759182. Epub 2018 Feb 12.


Functional connectivity of blood oxygenation level dependent signal fluctuations (BOLD-FC) is decreased in Alzheimer's disease (AD), and suggested to reflect reduced coherence in neural population activity; however, as both neuronal and vascular-hemodynamic processes underlie BOLD signals, impaired perfusion might also contribute to reduced BOLD-FC; 42 AD patients and 27 controls underwent simultaneous PET/MR imaging. Resting-state functional MRI assessed BOLD co-activity to quantify BOLD-FC, pulsed arterial spin labeling (pASL) assessed cerebral blood flow (CBF) as proxy for vascular hemodynamics, and 18F-fluorodeoxyglucose PET assessed glucose metabolism (GluMet) to index neuronal activity. Patients' BOLD-FC, CBF, and GluMet were reduced within the same precuneal parietal regions. BOLD-FC was positively associated with mean CBF, specifically in patients and controlled for GluMet levels, suggesting that BOLD-FC reductions correlate with pASL-derived hypoperfusion in AD, independently from 18F-fluorodeoxyglucose PET-derived hypometabolism. Data indicate that impaired vascular hemodynamic processes contribute to reduced BOLD connectivity in AD.

Keywords: Alzheimer’s disease; F-fluorodeoxyglucose-positron emission tomography; arterial spin labeling; blood oxygenation level dependent-functional connectivity; resting-state fMRI.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aged
  • Aged, 80 and over
  • Alzheimer Disease / physiopathology*
  • Brain / blood supply
  • Brain / physiopathology
  • Cerebrovascular Circulation / physiology*
  • Female
  • Fluorodeoxyglucose F18
  • Hemodynamics / physiology
  • Humans
  • Magnetic Resonance Imaging
  • Male
  • Middle Aged
  • Neurons / physiology
  • Oxygen / blood*
  • Positron-Emission Tomography
  • Signal Transduction / physiology*


  • Fluorodeoxyglucose F18
  • Oxygen