CONTRIBUTION OF TAU, TDP-43, β-AMYLOID AND α-SYNUCLEIN TO MEDIAL TEMPORAL LOBE ATROPHY

Abstract

Background: The Risk Reduction for Alzheimer’s Disease (rrAD) trial is designed to assess the effects of aerobic exercise and intensive vascular risk reduction on cognitive performance in older adults who are at high risk for AD. About 640 normal adults age 60 to 85 years with family history of dementia or subjective memory complaints, hypertension, and a sedentary life style are being enrolled at four clinical sites. BrainMRI scans are obtained at baseline and 24 months, and are being processed centrally at the trial imaging coordinating center (ICC). We aims to share our experience from our neuroimaging core. Methods: Data Acquisition: 3T MRI scanners (GE, Siemens and Philips) are used. The sequences used include: 3D T1-weighted high-resolution MPRAGE to quantify brain morphometry; T2 FLAIR tomeasurewhite matter lesions; DTI to assess brain white matter microstructural integrity and structural connectivity; resting-state fMRI to assess neural functional connectivity; 3D pCASL to assess regional brain perfusion; T2*weighted imaging to detect hemorrhage; and phase-contrast imaging to measure blood flow into the brain. Quality Control: All images are transferred via the web-based Globus software (https://www.globus.org/) in DICOM format to the ICC within 24 hours after acquisition. The ICC team completes quality control (QC) within three business days. The QC ensures subject anonymity, accuracy and image quality (imaging distortion, artifacts and signal-to-noise ratio) for all scans. The data collection sites are notified immediately if any severe image artifacts and clinically significant lesions are found. Recommendations are provided if a participant should be rescanned and/or if phantom QC scans should be performed (Fig. 1). Data Analysis: All imaging results are aligned to 3D MPRAGE images. MPRAGE images are segmented and standardized to MNI305 space using FreeSurfer. To reduce the impact of atrophy and distortion in older brains for group analyses, imaging results are standardized to MNI space via the FreeSurfer pipeline (Fig. 2). Results: With vigorous subject recruitment, data acquisition, QC and data analysis procedures, we have acquired over 350 high-qualityMRI datasets by January 2019. Scanner hardware issues have been timely detected and resolved to reduce scan delay. Conclusions: Successful procedures of a multicenter neuroimaging trial are demonstrated. IC-P-042 DIFFERENTIATING TAUOPATHIES WITH A NOVEL DIFFUSION TENSOR IMAGING METHOD TO INVESTIGATE CORTICAL ARCHITECTURE