Journal Article

Multi-parametric 18FPI-2620 tau PET/MRI for the phenotyping of different Alzheimer’s disease variants

Schroeter, Matthias L., Scherlach, Cordula, Strauss, Maria, Classen, Joseph, Rullmann, Michael, Koglin, Norman, Mishchenko, Olena, Brendel, Matthias, Tiepolt, Solveig, Hesse, Swen, Stephens, Andrew W., Henssen, Dylan, Hoffmann, Karl-Titus, Schildan, Andreas, Melasch, Juliana T., Saur, Dorothee, Barthel, Henryk, Sabri, Osama

2025

Overview

Purpose Heterogeneity in clinical phenotypes has led to the description of different phenotypes of Alzheimer’s disease (AD). Besides the most frequent amnestic variant of AD (aAD), patients presenting with language deficits are diagnosed with logopenic variant primary progressive aphasia (lvPPA), whereas patients presenting with visual deficits are classified as posterior cortical atrophy (PCA). Methods This study set out to investigate the value of a multi-parametric [ 18 F]PI-2620 tau PET/MRI protocol to distinguish aAD, lvPPA and PCA to support clinical diagnosis in 32 patients. Phenotype-specific information about tau accumulation, relative perfusion, grey matter density, functional network alterations and white matter microstructural alterations was collected. Results The aAD patients showed significantly higher tau accumulation, relative hypoperfusion and grey matter density loss in the temporal lobes compared to PCA and lvPPA patients. PCA patients, on the other hand, showed significantly higher tau accumulation in the occipital lobe as compared to aAD patients. Relative hypoperfusion in the occipital lobe and loss of functional connectivity of the posterior cingulate cortex to supplementary visual cortical regions helped to distinguish PCA from lvPPA. Tau accumulation in the cerebellum and microstructural changes in the cingulum were found to help differentiate lvPPA from aAD. Conclusion This study highlights structural and functional differences between patients with different AD phenotypes. Differences in regional tau PET signals suggest that refinements in the Braak staging system are needed for the non-aAD cases. These patterns of tau accumulation align with the cascading network failure hypothesis, though more research is needed to warrant the here presented results in larger patient cohorts.

• Publisher: Springer Berlin Heidelberg,Springer Nature B.V
• Subject: Accumulation / Aged / Alzheimer Disease - classification / Alzheimer Disease - diagnostic imaging / Alzheimer Disease - metabolism / Alzheimer's disease / Aphasia / Atrophy / Cardiology / Cerebellum / Cingulum / Cortex (cingulate) / Density / Female / Fluorine isotopes / Heterogeneity / Humans / Imaging / Magnetic Resonance Imaging / Male / Medicine / Medicine & Public Health / Middle Aged / Multimodal Imaging / Neurodegenerative diseases / Nuclear Medicine / Occipital lobe / Oncology / Original / Original Article / Orthopedics / Phenotype / Phenotypes / Phenotyping / Positron emission / Positron-Emission Tomography / Pyridines / Radiology / Structure-function relationships / Substantia alba / Substantia grisea / Tau protein / tau Proteins - metabolism / Temporal lobe