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

Area of Science:

• Neuroimaging
• Neurology
• Biomarker Discovery

Background:

• Cerebral blood flow (CBF) is tightly linked to brain metabolism and can be quantified non-invasively using Arterial Spin Labeled perfusion Magnetic Resonance Imaging (ASL MRI).
• Altered regional CBF is observed in neurodegenerative diseases, suggesting its potential as a biomarker.
• Mild cognitive impairment (MCI) is an early stage of cognitive decline, often preceding Alzheimer's disease.

Purpose of the Study:

• To investigate the utility of task-enhanced ASL MRI in differentiating individuals with amnestic mild cognitive impairment (aMCI) from healthy controls.
• To assess whether functional brain imaging during a cognitive task improves the detection of subtle brain changes in early neurodegenerative processes.

Main Methods:

• ASL MRI was used to measure CBF in subjects with aMCI (n=65) and cognitively normal controls (n=62) at rest and during a memory-encoding task.
• Cognitive performance and structural MRI data were also acquired.
• Logistic regression analysis was employed to evaluate the diagnostic power of ASL MRI and structural MRI.

Main Results:

• Task-enhanced ASL MRI demonstrated improved discrimination between the aMCI and control groups compared to resting-state measurements.
• ASL MRI and structural MRI provided complementary information regarding disease status.
• The findings suggest that physiological measures during cognitive challenge enhance the detection of early functional changes.

Conclusions:

• Task-enhanced ASL MRI shows significant potential as a sensitive biomarker for detecting early-stage Alzheimer's disease and related cognitive impairments.
• Integrating functional (ASL MRI) and structural MRI may offer a more comprehensive assessment of disease status.
• Cognitive stress testing using ASL MRI can reveal subtle alterations in brain function indicative of neurodegeneration.