VALIDATION OF HIPPOCAMPAL TEXTURE FOR EARLY ALZHEIMER'S DISEASE DETECTION: GENERALIZATION TO INDEPENDENT COHORTS AND EXTRAPOLATION TO VERY EARLY SIGNS OF DEMENTIA

neurofibrillary tangles than LOAD patients. However, these findings have not been substantiated in clinical studies. Studies using Positron Emission Tomography (PET) with carbon-11-labelled Pittsburgh compound-B (PiB) were not conclusive in replicating the post-mortem findings. A previous study suggested that iron accumulation, which may reveal AD pathology and more specifically amyloid deposition, is reflected by phase information from 7T T 2*-weighted MRI sequences. The aim of this study is to explore regional iron-related differences in the cerebral cortex, indicative of AD pathology, between EOAD and LOAD patients using 7T MR phase images. Methods: 12 EOAD patients, 17 LOAD patients and 17 healthy elderly controls (table 1) were scanned at 7T using a 2D transverse T 2*-weighted scan with a total imaging duration of 10 minutes. MRI scans were analyzed quantitatively by measuring lobar peak-to-peak phase shifts in the frontal, parietal, and left and right temporoparietal regions. Cortical parcellation was performed on the T 2*-weighted images using the segmented cortex and an anatomical atlas (AAL atlas) (figure 1). The regional mean gray matter (GM)/ white matter (WM) contrast was computed as the difference between the mean phase value of the GM and WM ROIs. Results: An increased peak-to-peak phase shift was found for all lobar regions in EOAD patients compared with LOAD patients (p1⁄40.05) (table 2). Regional mean phase contrast in EOAD patients was higher than in LOAD patients in the superior medial and middle frontal gyrus, anterior and middle cingulate gyrus, postcentral gyrus, superior and inferior parietal gyrus, and precuneus (p<0.042) (table 3). Conclusions: These data suggest that EOAD patients have an increased iron accumulation, as compared with LOAD patients, in specific cortical regions, which could also be related to increased amyloid deposition.