Sepi Shokouhi
Vanderbilt University Institute of Imaging Science, USA
Biography
T2-weighted magnetic resonance images (MRI) can display cerebral white matter intensity changes, which are common in elderly subjects and linked to vascular diseases. Few studies have investigated the spatial and temporal associations between the white matter intensity distribution and the retention of amyloid-PET radiotracers Florbetapir and PiB. In this study, we explore these correlations using data from Alzheimer’s disease neuroimaging initiative (ADNI). One of the main objectives is to determine whether the selection of the radiotracer can alter these associations. Methods: For both PET data, we used images with minimum amount of smoothing in order to preserve spatial clusters in images and to determine whether white matter T2 voxel intensity values in the vicinity of high activity clusters in amyloid PET images are different than other areas. These localized spatial correlations were explored by utilizing a new image analysis approach that is based on a randomized sampling of voxel pairs between the two modalities. Results: While in several subjects we observed a slight T2 increase in areas close to the high activity PET clusters, there were some regional and inter-subject variabilities, which could be due to regional differences in amyloid clearance mechanism or the presence of cerebral amyloid angiopathy. However, further studies are required to verify these hypotheses. Conclusion: This study provides new imaging-based methodologies to investigate the presence of subtle within-subject spatial associations between amyloid PET radiotracer retention and its surrounding white matter in Alzheimer’s disease.