Quantitative T1 mapping (qT1) is a magnetic resonance imaging (MRI) biomarker of brain microstructural changes; however, its application in Alzheimer disease (AD) remains limited. We compared cortico-limbic qT1 values between patients with AD and healthy controls (HCs) and examined their relationship with amyloid burden measured by amyloid-positron emission tomography (PET). We retrospectively identified subjects with mild cognitive impairment due to AD and HCs who underwent 3-T MRI, including a compressed-sensing MP2RAGE sequence, generating three-dimensional T1-weighted images and qT1 maps. Amyloid-PET was available for 16 patients. Hippocampal qT1 and volume were compared between groups, adjusting for age and sex; analyses were repeated after stratifying patients by Mini-Mental State Examination (MMSE). Voxel-wise group comparison was performed using SPM 12. The qT1-standardized uptake value ratio (SUVr) association was assessed with a linear mixed-effects model applied to voxel-level data, accounting for partial volume effects. Thirty-three AD subjects, aged 69.3 ± 8.2 years (mean ± standard deviation), 18 females, and 22 HCs aged 70.5 ± 13.3 years, 15 females, were evaluated. Regional hippocampal qT1 was higher in AD (1,398 ± 53.0 ms versus 1,349 ± 53.4 ms; p = 0.002), without difference across cognitive subgroups stratified by MMSE. AD subjects exhibited increased qT1 in mesial temporal gray matter and temporo-parieto-occipital cortices (1,448 ± 55.7 ms versus 1,344 ± 51.6 ms; p < 0.001). Voxel-level modelling revealed a positive association between qT1 and amyloid-PET SUVr (p < 0.001; d = 0.223). qT1 mapping can be sensitive to changes related to brain amyloidosis, supporting its role as a promising, noninvasive imaging biomarker in AD. Question Can qT1 mapping detect AD-related microstructural changes in the cortico-limbic gray matter? Findings Participants with AD showed increased cortico-limbic qT1 values. A subtle yet consistent positive association was observed between cortical qT1 values and amyloid-PET SUVr. Relevance statement qT1 mapping captures microstructural tissue alterations related to amyloid pathology in Alzheimer’s disease, supporting its role as a potential non-invasive imaging biomarker in this condition.
L. Gualco, Noemi Montobbio, M. Losa et al.· European Radiology Experimen...· 0 citations
The Amyloid Imaging to Prevent Alzheimer’s Disease Prognostic and Natural History Study (AMYPAD-PNHS) multimodal magnetic resonance imaging (MRI) dataset provides open-access longitudinal MRI data of 2759 cognitively normal or mild cognitive impairment individuals, encompassing (micro-)structural, physiological, and functional MRI sequences from 10 European parent cohorts. Processed and raw images, and image-derived (endo-)phenotypes, are organized in Brain Imaging Data Structure (BIDS) standards and accessible upon request, to enhance generalizability and comparability between future neuroimaging studies. This dataset supports preclinical Alzheimer’s disease (AD) and aging-related research by enabling robust multimodal analyses of neurodegeneration, microvascular pathology, and structural and functional connectivity changes, facilitating advanced investigations into preclinical AD mechanisms, informing early intervention strategies and allowing reproducible and centralized neuroimaging (endo-)phenotyping.
L. Pieperhoff, M. Tranfa, Prithvi Arunachalam et al.· Scientific Data· 0 citations
Abstract INTRODUCTION Tau positron emission tomography (PET) probes Alzheimer's disease (AD) severity via regional tau spread but is not widely available. We tested whether multiregion structural magnetic resonance imaging (MRI) could approximate individual tau burden. METHODS We studied 378 Alzheimer's Disease Neuroimaging Initiative (ADNI) participants with mild cognitive impairment (MCI)‐AD or AD dementia with paired T1‐MRI and [18F]flortaucipir tau‐PET (≤6 months apart). Regional cortical thickness and volume were extracted with FreeSurfer. Principal component analysis and multivariable linear regression yielded MRI signatures of tau‐PET standardized uptake value ratio (SUVR) in Braak composite regions (I, III–IV, V–VI), a meta‐temporal region of interest (ROI), and a global neocortical meta‐ROI. Performance and high/low tau classification were evaluated by leave‐one‐out cross‐validation against published cut‐offs. RESULTS MRI signatures were significantly associated with tau‐PET burden across all regions (p < 0.001). High‐versus‐low tau discrimination varied: AUC ≈ 0.70 in Braak I, ≈0.89 in Braak V–VI, and ≈0.90 globally. Discussion Here we provide proof‐of‐concept evidence that multiregion T1‐MRI patterns can inform on tau‐PET burden in AD and may support approximate tau staging when tau‐PET is unavailable, especially in subjects with more advanced tau burden.
Martina Pulze, S. Garbarino, L. Lorenzini et al.· Alzheimer's & Dementia· 0 citations
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