Adolf Pfefferbaum1,2, Elfar Adalsteinsson3,4, Torsten Rohlfing1, Edith Sullivan2
1Neuroscience Program, SRI International, Menlo Park, CA, USA; 2Department of Psychiatry and Behavioral Sciences, Stanford University School of Medicine, Stanford, CA, USA; 3Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology, Cambridge, MA, USA; 4Harvard-MIT Division of Health Sciences & Technology, Massachusetts Institute of Technology, Cambridge, CA, USA
Different brain structures accumulate iron at different rates throughout aging. Brain iron can be measured by estimating the relaxivity increase from 1.5T to 3.0T - MR Field Dependent R2 Increase (FDRI). Local iron influence on MR phase forms the basis for Susceptibility-Weighted Imaging (SWI) and requires imaging at only one field strength. We showed that both methods detect high globus pallidus iron concentration regardless of age and significantly greater iron in putamen with advancing age. While FDRI requires more imaging time, two field strengths, and across-study image registration for iron concentration calculation, FDRI is more specific to iron than SWI.