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P3‐389: AV1451 TAU TRACER UPTAKE CORRELATES WITH HIPPOCAMPAL CA1 SUBFIELD ATROPHY IN AMYLOID‐NEGATIVE INDIVIDUALS
Author(s) -
Das Sandhitsu R.,
Ittyerah Ranjit,
Wisse Laura,
Xie Long,
Yushkevich Paul,
Wolk David A.
Publication year - 2018
Publication title -
alzheimer's and dementia
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 6.713
H-Index - 118
eISSN - 1552-5279
pISSN - 1552-5260
DOI - 10.1016/j.jalz.2018.06.1751
Subject(s) - subiculum , entorhinal cortex , perirhinal cortex , hippocampal formation , parahippocampal gyrus , temporal lobe , tauopathy , atrophy , dentate gyrus , hippocampus , neuroscience , psychology , temporal cortex , pathology , medicine , neurodegeneration , disease , epilepsy
Background:We present novel preliminary data demonstrating relationships between the amount of tau binding measured by AV1451 PET imaging and atrophy within hippocampal subfields measured by hippocampus-focused high-resolution structural MRI in individuals classified as either Amyloid-b positive or negative based on Florbetapir-PET imaging. While the cornu ammonis 1 (CA1) subfield is known to be an early site of tau pathology in Alzheimer’s disease (AD) and Primary Age Related Tauopathy (PART, defined by the presence of tau-based neurofibrillary tangles in the absence of amyloid), it is unclear how tau pathology in PART relates to subfield structure. Methods: The dataset included 80 participants (27 Ab positive: 9 controls, 13 Mild Cognitive Impairment (MCI), 5 AD; 53 Ab negative: 37 controls, 14 MCI, 2 AD) in the ADNI study. Normalized tau tracer uptake in the medial temporal lobe (MTL) was measured from AV1451 PET within a composite cortical ROI consisting of Brodmann area 35 (BA35) region of perirhinal cortex and entorhinal cortex. Hippocampus wasn’t included to avoid a known confound of high choroid plexus uptake. Hippocampal subfield volumes (CA1, CA4 and dentate gyrus (DG), subiculum (SUB)) were measured from high-resolution T2-weighted structural MRI using a joint label fusion technique implemented in the ASHS software. Results: Both PET and atrophy measures were averaged across the hemispheres. We correlated a summary measure of MTL tau tracer uptake with hippocampal subfield volumes, with age and intracranial volume as covariates. In the Ab positive group, CA1 had the strongest correlation with tracer uptake, followed by CA4DG, and SUB being marginally significant. In the Ab negative group, all three subfields had significant correlation with tracer uptake, with CA1 marginally stronger than