A brain stress test: Cerebral perfusion during memory encoding in mild cognitive impairment

Neuroimage Clin. 2016 Mar 2;11:388-397. doi: 10.1016/j.nicl.2016.03.002. eCollection 2016.

Abstract

Arterial spin labeled perfusion magnetic resonance imaging (ASL MRI) provides non-invasive quantification of cerebral blood flow, which can be used as a biomarker of brain function due to the tight coupling between cerebral blood flow (CBF) and brain metabolism. A growing body of literature suggests that regional CBF is altered in neurodegenerative diseases. Here we examined ASL MRI CBF in subjects with amnestic mild cognitive impairment (n = 65) and cognitively normal healthy controls (n = 62), both at rest and during performance of a memory-encoding task. As compared to rest, task-enhanced ASL MRI improved group discrimination, which supports the notion that physiologic measures during a cognitive challenge, or "stress test", may increase the ability to detect subtle functional changes in early disease stages. Further, logistic regression analysis demonstrated that ASL MRI and concomitantly acquired structural MRI provide complementary information of disease status. The current findings support the potential utility of task-enhanced ASL MRI as a biomarker in early Alzheimer's disease.

Keywords: AAL, Anatomical Automatic Labeling; ASL, arterial spin labeled; Alzheimer's disease; Arterial spin labeling; BOLD, blood oxygen level dependent; Biomarker; CBF, cerebral blood flow; CSF, cerebrospinal fluid; FDG PET, flourodeoyglucose positron emission tomography; FWER, familywise error rate; HC, health control; MCI, mild cognitive impairment; MMSE, mini-mental status exam; MNI, Montreal Neurological Institute; MTL, medial temporal lobe; Medial temporal lobe; PASL, pulsed ASL; PCC, posterior cingulate cortex; ROI, region of interest; SCORE, structural correlation based outlier rejection; Scene-encoding memory task; a-MCI, amnestic mild cognitive impairment; aCBF, absolute cerebral blood flow; pCASL, pseudo-continuous ASL; rCBF, relative cerebral blood flow.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Aged
  • Aged, 80 and over
  • Analysis of Variance
  • Brain Mapping*
  • Cerebral Cortex / blood supply
  • Cerebral Cortex / diagnostic imaging*
  • Cerebrovascular Circulation / physiology*
  • Cognitive Dysfunction / diagnosis*
  • Cognitive Dysfunction / physiopathology*
  • Female
  • Hippocampus / blood supply
  • Hippocampus / diagnostic imaging
  • Humans
  • Image Processing, Computer-Assisted
  • Magnetic Resonance Angiography
  • Male
  • Memory / physiology*
  • Middle Aged
  • Photic Stimulation
  • Psychometrics