Xiaojun Xu, Presenter: Nothing to Disclose

Qidong Wang, Abstract Co-Author: Nothing to Disclose

Minming Zhang MD, PhD, Abstract Co-Author: Nothing to Disclose

It is well known that iron accumulates in the brain for people with a variety of neurodegenerative diseases. To better understand disease-related iron changes, it is necessary to know the physiological distribution of iron content in the human brain. Studies have showed that brain iron levels increase with aging. However, few studies focused on the gender and hemispheric difference in the iron content. In this study, we measured the brain iron level in a life span sample of healthy adults using susceptibility-weighted imaging (SWI) to assess the effects of age, gender and hemispheric location on the iron content.

78 healthy adult volunteers with an age range of 22 to 78 were studied with a GE 1.5T scanner. The study population consisted of 40 male and 37 female. SWI images were taken with a 3D GRE sequence: TR = 51ms, TE =38ms, FA = 20°, Nz =28 slices, slice thickness = 2mm, FOV = 24cm and matrix size (Nx × Ny) = 256 × 256. The phase values, which are negative correlate with brain iron levels, were measured on the “corrected” phase image in the bilateral globus pallidus, putamen, caudate, thalamus, substantia nigra, red nucleus, and frontal white matter. The effects of age, gender, and hemispheric location on the brain iron level were evaluated within a mixed linear model.

There were significant age-related iron accumulation in the putamen, red nucleus, and frontal white matter. No gender-related differences in iron level were detected in any of the region we studied. The left hemisphere had much higher iron level than the right in the putamen, globus pallidus，substantia nigra, thalamus and frontal white matter.

This is the first demonstration of hemispheric asymmetry of iron level in the human brain. We proposed that the leftward asymmetry of the brain levels may be related to the dopaminergic asymmetry between two hemispheres. The results of the study also replicate the findings of age-related iron deposition in the brain in vivo.

The results of this study extend our knowledge of the physiological distribution and accumulation of iron in the human brain. It is a necessary baseline to understand disease-related iron deposition.

Xu, X, Wang, Q, Zhang, M, Age, Gender, and Hemispheric Differences in Iron Content of the Human Brain: An in Vivo MRI Study.  Radiological Society of North America 2007 Scientific Assembly and Annual Meeting, November 25 - November 30, 2007 ,Chicago IL. http://archive.rsna.org/2007/5013081.html