R2* mapping for brain iron: associations with cognition in normal aging

Area of Science:

• Neuroscience
• Radiology
• Gerontology

Background:

• Brain iron accumulation is a hallmark of aging and linked to neurodegenerative diseases like Alzheimer's.
• Magnetic resonance (MR)-based R2* mapping allows in vivo quantification of brain iron content.

Purpose of the Study:

• To investigate the relationship between age-related brain iron load and cognitive impairment.
• To examine region-specific patterns of iron accumulation and cognitive decline in healthy adults.

Main Methods:

• Utilized MR imaging and R2* mapping at 3T in 336 healthy middle-aged and older adults.
• Assessed cognitive domains including memory, executive function, and psychomotor speed through comprehensive neuropsychological testing.
• Focused analysis on iron content in the basal ganglia and neocortex.

Main Results:

• The highest iron concentration was observed in the globus pallidus.
• Increased iron in the globus pallidus and putamen was significantly associated with impaired cognitive performance across most domains, excluding memory.
• These associations demonstrated a clear iron load dependency.
• Vascular brain lesions and reduced brain volume did not mediate the observed iron-cognitive performance relationship.

Conclusions:

• Higher R2*-determined iron levels in the basal ganglia correlate with cognitive impairment during brain aging.
• This association appears independent of other common brain abnormalities like lesions or volume loss.
• Further research is needed to determine the prognostic significance of these iron-related cognitive changes.