Arnold Moya Evia BS, Presenter: Nothing to Disclose

David A. Bennett MD, Abstract Co-Author: Nothing to Disclose

Julie A. Schneider MD, Abstract Co-Author: Nothing to Disclose

Aikaterini Kotrotsou PhD, Abstract Co-Author: Nothing to Disclose

Robert Dawe PhD, Abstract Co-Author: Nothing to Disclose

Konstantinos Arfanakis PhD, Abstract Co-Author: Nothing to Disclose

Iron accumulation in the brain has been associated with aging, and Alzheimer’s disease (AD). MRI techniques that allow detection of iron accumulation may lead to development of biomarkers of AD pathology. Quantitative susceptibility mapping (QSM) was introduced recently, and is shown to be sensitive to changes in iron levels. Therefore, the purpose of this study was to investigate the neuropathologic correlates of magnetic susceptibility in subcortical gray matter, by conducting an ex-vivo QSM-pathology investigation of AD in a community cohort.

Cerebral hemispheres were obtained from 94 participants (90±6 years of age; 26 males) of the Rush Memory and Aging Project and the Religious Orders Study. All hemispheres were submerged in 4% formaldehyde solution early after death, and were imaged approximately 30 days postmortem. MRI data was collected using: a 3D multi-echo gradient-echo sequence and a multi-echo fast spin-echo sequence. Following ex-vivo MRI, hemispheres underwent neuropathologic assessment by a board-certified neuropathologist blinded to all clinical and imaging findings. A composite measure of global AD pathology was created from counts of neurofibrillary tangles, neuritic and diffuse plaques. QSM maps were created with a magnitude-weighted L1-regularization algorithm. Susceptibility maps from all participants were spatially normalized. Putamen and caudate were outlined on the template and the outlines were superimposed onto the spatially transformed susceptibility maps. Linear regression was used in each region to investigate the link between median susceptibility values and the composite measure of global AD pathology, controlling for age at death, sex, and postmortem interval to imaging. Statistical significance was set at p<0.05.

Statistically significant positive correlations were detected between magnetic susceptibility values and the composite measure of global AD pathology in the putamen (p=0.035) and caudate (p=0.021).

These findings suggest that magnetic susceptibility values in subcortical gray matter measured with QSM are sensitive to AD pathology. This study provides a strong indication that QSM may play an important role in the development of biomarkers of AD pathology.

These results suggest that QSM may be sensitive to iron accumulation due to AD pathology.

Evia, A, Bennett, D, Schneider, J, Kotrotsou, A, Dawe, R, Arfanakis, K, Ex-vivo Quantitative Susceptibility Mapping Shows a Correlation between Magnetic Susceptibility and Alzheimer's Pathology.  Radiological Society of North America 2014 Scientific Assembly and Annual Meeting, - ,Chicago IL. http://archive.rsna.org/2014/14019585.html