MULTIMODAL IMAGING CORRELATIONS IN EARLY ALZHEIMER’S DISEASE: AMYLOID, TAU, AND NEURITE IMAGING

Abstract

In Alzheimer's disease (AD), various multimodal imaging methods are developing, such as Tau PET or advanced diffusion MRI. The aim of this study is to investigate the findings of those imaging modalities in AD and the correlations among them. We recruited 16 patients with early AD (5 males, mean ± SD age: 70.8 ± 7.5 years, mean ± SD MMSE: 22.7 ± 4.3, all PiB-positive), and 18 healthy controls (8 males, mean ± SD age: 66.8 ± 9.5 years, mean ± SD MMSE: 29.2 ± 1.0, all PiB-negative). All participants underwent conventional MRI, 11C-PiB-PET, 18F-THK5351-PET, and diffusion images at two b-values (1000 and 2000 s/mm2) which provided neurite density and dispersion images using NODDI toolbox. After normalization with SPM12, we estimated the voxel-by-voxel correlations in AD patients among those modalities using Biological Parametric Mapping toolbox, in addition to group comparisons in each modality. Compared to controls, AD patients showed broad Tau deposition especially in bilateral inferolateral temporal lobes, decreased neurite density in right hippocampus and front-parietal lobe, and decreased neurite dispersion mainly in right temporal lobe. Additionally, there were negative voxel-by-voxel correlations in bilateral temporal lobes between gray matter and Tau deposition, in right middle frontal gyrus between neurite density and Tau deposition, and in right temporal lobe between neurite dispersion and Tau deposition. These findings from advanced imaging techniques could reflect the pathology of AD, such as the relationship of abnormal accumulation to neuro-degeneration, and contribute to the better understanding of AD.