Age, gender, and hemispheric differences in iron deposition in the human brain: an in vivo MRI study
It is well known that iron accumulates in the brains of patients with\nvarious neurodegenerative diseases. To better understand disease-related\niron changes, it is necessary to know the physiological distribution\nand accumulation of iron in the human brain. Studies have shown that\nbrain iron levels increase with aging. However, the effects of gender\nand hemispheric laterality on iron accumulation and distribution\nare not well established. In this study, we estimated the brain iron\nlevels in vivo in 78 healthy adults ranging in age 22 to 78 years\nusing magnetic susceptibility-weighted phase imaging. The effects\nof age, gender, and hemispheric location on brain iron levels were\nevaluated within the framework of a general linear model. We found\nthat the left hemisphere had higher iron levels than the right in\nthe putamen, globus pallidus, substantia nigra, thalamus, and frontal\nwhite matter. We argue that the hemispheric asymmetry of iron content\nmay underlie that of the dopaminergic system and may be related to\nmotor lateralization in humans. In addition, significant age-related\niron accumulation occurred in the putamen, red nucleus, and frontal\nwhite matter, but no gender-related differences in iron levels were\ndetected. The results of this study extend our knowledge of the physiological\ndistribution and accumulation of iron in the human brain.