Lorenzo Gualco, Noemi Montobbio, Mattia Losa, Mauro Costagli, Federico Massa, Beatrice Orso, Lucia Argenti, Enrico Peira, Andrea Chincarini, Silvia Morbelli, Stefano Raffa, Luca Sofia, Gianmario Sambuceti, Luigi Lorenzini, Emanuele Pravatà, Massimo Caulo, Martina Pulze, Dario Arnaldi, Andrea Diociasi, Domenico Zacà, Gian Franco Piredda, Tom Hilbert, Tobias Kober, Marco Bozzali, Maria Pia Sormani, Matteo Pardini, Luca Roccatagliata
qT1 mapping can be sensitive to changes related to brain amyloidosis, supporting its role as a promising, noninvasive imaging biomarker in AD.
OBJECTIVES: 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).
MATERIALS AND METHODS: 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.
RESULTS: 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).
CONCLUSION: qT1 mapping can be sensitive to changes related to brain amyloidosis, supporting its role as a promising, noninvasive imaging biomarker in AD.
KEY POINTS: 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.