clinical and neurocognitive outcome. First group consisted of MCI patients who progressed to AD after follow-up period (CDR=1; 11 patients; 7 women, 4 men) and second group consisted of patients who had stable symptoms of MCI (CDR=0.5; 8 patients; 3 women, 5 men). The relation- ship between hippocampal volume z-score and the risk of developing AD over a two-year period of observation adjusted for age and sex interaction in logistic regression model was Rsquare=0.65; p=0.045 for left hip- pocampus and Rsquare=0.56; p=0.055 for right hippocampus. Conclu- sions: Initial hippocampal volume may influence the dynamics of cognitive decline in MCI patients over a two-year period of observation. The differ- ence of effect between sides suggests higher sensitivity of left hippocampal volume as a predictive marker of AD. However lack of normative values of hippocampal volume mean and SD for elderly population limits calcu- lated z-score to studied population. IC-P-071 THE EFFECT OF APOE-4 ON FMRI DEACTIVATION IN OLDER CONTROLS, MCI SUBJECTS AND AD PATIENTS Maija Pihlajamaki 1,2 , Saul M. Miller 1,3 , Kristina M. DePeau 1,3 , Kim A. Celone 1,3 , Lars Bertram 3 , Rudolph E. Tanzi 3 , Bradford C. Dickerson 1,3 , Marilyn S. Albert 4 , Deborah Blacker 3 , Reisa A. Sperling 1,3 , 1 Department of Neurology, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA, USA; 2 Department of Neuroscience and Neurology, University of Kuopio, Kuopio, Finland; 3 Departments of Neurology/Psychiatry/Radiology/Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Boston, MA, USA; 4 Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD, USA. Contact e-mail: mpihlajamaki@rics.bwh.harvard.edu Background: The epsilon 4 allele of apolipoprotein E (APOE-4) is a known risk factor for Alzheimer’s disease (AD). PET studies of non- demented APOE-4 carriers have revealed hypometabolism of posterior association cortices, particularly in posterior cingulate and parietal regions, similar to the pattern of metabolic abnormalities seen in AD patients. A similar set of regions have shown alterations in deactivation, or “default mode activity,” in fMRI studies of AD patients. Objective: We wanted to investigate the effect of APOE-4 on fMRI deactivation pattern in aging, MCI and early AD. Methods: A total of 82 older subjects underwent fMRI during a face-name associative encoding paradigm. At least one APOE-4 allele was present in 8/29 (28%) of older controls (OC), in 13/38 (34%) of subjects with mild cognitive impairment (MCI, defined here as CDR 0.5), and in 9/15 (60%) of patients with early AD. FMRI was performed using a 3.0T scanner, oblique coronal acquisition, and spatial resolution of 3.125x3.125x6 mm. Data were analyzed using FEAT5.43 software con- trasting the passive fixation baseline to the encoding novel and repeated face-name pairs; peak z-values and corresponding uncorrected p-values for the within and between-group comparisons are reported. Results: The OC group demonstrated significant deactivation in posterior cingulate/retro- splenial, and precuneal regions (corresponding to Brodmann areas 23/29/ 30/31; z=4.83, p0.0001). OC APOE-4 carriers showed less deactivation in both regions compared to OC non-carriers (z=3.55, p0.0001). The deactivation pattern of MCI subjects was heterogeneous varying both according to their level of impairment and APOE-4 status. AD patients showed significantly less deactivation than OC in medial parietal and cingulate/retrosplenial cortices (z=5.32, p0.0001). Comparing OC and AD subgroups, we found evidence of a hierarchy of deactivation decreas- ing in the following order: OC APOE-4 non-carriers  OC APOE-4 carriers  AD APOE-4 non-carriers  AD APOE-4 carriers. Conclusions: The present study demonstrates that the pattern of task-related fMRI deactivation is remarkably disrupted in AD patients, particularly in AD APOE-4 carriers. Furthermore, consistent with PET findings, APOE-4 was associated with impaired parietal and posterior cingulate deactivation even in cognitively intact older individuals at risk for AD. Supported by NINDS K23-NS02189;NIA PO1-AG04953;NIA P50- AG00513421;Academy of Finland. IC-P-072 CONTRAST BOLUS MAGNETIC RESONANCE IMAGING IN ALZHEIMER’S DISEASE AND MILD COGNITIVE IMPAIRMENT Louise Gyldensted 1,2 , Kim Mouridsen 1,2 , Anders Rodell 2 , Leif Østergaard 1,2 , Carsten Gyldensted 1 , 1 Dep. of Neuroradiology, Aarhus University Hospital, Aarhus, Denmark; 2 CFIN, Aarhus University Hospital, Aarhus, Denmark. Contact e-mail: lg@pet.auh.dk Background: Alzheimer’s disease (AD) is associated with several vascu- lar risk factors pointing to microvascular insufficiency of gray and white matter in AD pathogenesis [1,2]. Cerebral perfusion measurements in AD with PET and SPECT show hypoperfusion in hippocampus, temporo- parietal and frontal cortices [3,4]. We hypothesize that perfusion-weighted (PW) MRI with subsequent co-registration can help delineate microvascu- lar perfusion abnormalities across AD patients and thus better characterize disease progression. Objectives: To study regional cerebral perfusion with PW-MRI in patients with AD and mild cognitive impairment (MCI) com- pared with controls. Methods: Eighteen patients clinically suspected of mild to moderate AD (n=15) or MCI (n=3) and 20 healthy age-matched controls were studied with PW-MRI on a 1.5 T GE scanner. Following an axial T1, Spin-Echo EPI was performed during i.v.-bolus injection (5 ml/sec) of 0.2 mmol/kg gadobutrol (Gadovist®1.0 M, Schering) flushed by 20 ml saline. Twelve axial slices were imaged at a spatial resolution of 1.6x1.6x6.0 mm and mean transit time (MTT) maps calculated [5]. 3D-T1 and PWI maps were co-registered to Talairach space [6]. After blurring (FWHM 8 mm) to avoid effects of atrophy, a voxel-by-voxel t-test was performed to identify areas with significant MTT differences between patient and control group. Results: MTT was higher (p0.01, uncor- rected) among patients than among controls in white and gray matter in right temporo-parietal watershed areas, temporal operculum, hippocam- pus, and bilaterally (most pronounced on right side) in parietal gray and subcortical white matter, cingulate gyrus and precuneus. (Fig. 1). Conclu- sion: Our finding of prolonged MTT indicates low perfusion pressure in accordance with PET findings of low CBF and the high incidence of watershed infarcts known from post-mortem AD studies. Group averages of functional MRI maps following co-registration provide a powerful tool for studying diffuse cerebral disease markers. By combining perfusion measurements (MTT, CBV and CBF) with indicators of tissue microstruc- tural damage (by Diffusion Tensor Imaging), we hope to further address the vascular and neurodegenerative pathogenesis of AD and MCI. Refer- ences: [1] de la Torre,JC:Neurosci.Behav.Rev.18:397-401,1994; [2] Brown,WR:Ann.NYAcad.Sci.903:39-45,2000; [3] Friedland,RP:JCAT 7:590-98,1983; [4] Waldemar,G:Cerebrovasc.BrainMetab.Rev.7:89- 130,1995; [5] Østergaard,L:MRM.36:715-25,726-36,1996; [6] Collins,DL: JCAT.18(2):192-205,1994. IC-P-073 OPEN ACCESS STRUCTURAL IMAGING SERIES (OASIS) Jamie B. Parker 1 , Daniel S. Marcus 2 , Tracy H. Wang 3 , Abraham Z. Snyder 2,4 , Laura E. Girton 5 , John C. Morris 6 , Randy L. Buckner 7,8 , 1 Department of Psychology, Harvard University, Cambridge, MA, USA; 2 Mallinckrodt Institute of Radiology, Washington University School of Medicine, St. Louis, MO, USA; 3 Department of S681 Imaging Consortium IC-P-101: Posters