SURFACE-BASED ANALYSIS OF SUB-CORTICAL STRUCTURES IN TAU AND AMYLOID PET IMAGING: AN ALZHEIMER'S DISEASE STUDY

Abstract

The extracellular amyloid plaques and neurofibrillary tangles are important hallmarks of Alzheimer disease (AD) spectrum. The recent development of positron emission tomography (PET) tracers has enabled human to detect neuritic plaques or neurofibrillary tangles in vivo. In this study, we recruited cognitive normal (CN) subjects (6 normal control and 27 subjective memory impairment subjects), 54 mild cognitive impairment (MCI) patients, 26 AD patients with T1-weighted brain magnetic resonance imaging (MRI), amyloid PET and tau PET. We constructed subcortical surface meshes and registered to the template mesh in order to provide vertex correspondences. Each vertices of subcortical surface acquired standardized uptake value ratios (SUVR) normalized by mean uptake of cerebellar cortex from PET images which were registered to the T1-weighted MRI images. We performed group comparison between three groups using permutation test and false discovery rate (FDR) correction. In the amyloid PET study, AD patients showed significant increased SUVR in the bilateral caudate nucleus, the bilateral putamen, the left globus pallidus, the right amygdala compared with CN subjects. Also SUVR in these subcortical regions and the right globus pallidus were higher in the MCI patients than CN subjects. Whereas SUVR of the bilateral hippocampus was higher in the CN subjects than AD patients. MCI patients had higher SUVR in the left hippocampus than AD patients. In the tau PET study, AD patients exhibited greater SUVR in the bilateral amygdala, the left hippocampus and the left putamen relative to CN subjects. Except for the left putamen, MCI patients had greater SUVR in the same regions relative to CN subjects. Contrary to the amyloid PET study, AD patients had greater SUVR in the left hippocampus than MCI patients.