Quantitative susceptibility mapping in β-Amyloid PET-stratified patients with dementia and healthy controls - A hybrid PET/MRI study.

Abstract

PURPOSE:

Post-mortem and in-vivo MRI data suggest an accumulation of iron in the brain of Alzheimer's disease (AD) patients. The majority of studies in clinically diagnosed AD patients found an increase of iron-sensitive MRI signals in the putamen. As the clinical diagnosis shows only a moderate sensitivity, Aβ-PET was used to further stratify patients with the clinical diagnosis of AD. Aim of this exploratory study was to examine whether Aβ-positive (AD) and Aβ-negative (non-AD) patients differ in their regional magnetic susceptibility compared to healthy controls (HCs) and whether regional susceptibility values correlate with mini mental state examination (MMSE) scores or global Aβ-load.

METHODS:

We retrospectively analyzed [11C]PiB PET/MRI data of 11 HCs, 16 AD and 10 non-AD patients. We used quantitative susceptibility mapping (QSM) as iron-sensitive MRI signal measured at the 3 T PET/MR scanner. Global cerebral Aβ-load was determined by composite [11C]PiB SUV ratios.

RESULTS:

Compared to HCs, AD patients showed higher QSM values in putamen (0.049 ± 0.033 vs. 0.002 ± 0.031; p = 0.006), while non-AD patients showed lower QSM values in caudate nucleus (0.003 ± 0.027 vs. 0.051 ± 0.039; p = 0.006). There was a trend towards a significant correlation between putaminal QSM and MMSE values (ρ=-0.340, p = 0.053). In AD patients, global Aβ-load and putaminal QSM values were significantly correlated (ρ=-0.574, p = 0.020).

CONCLUSIONS:

These data indicate that AD and non-AD patients may show different cerebral iron pathologies which might be detectable by QSM MRI, and might be linked to neurodegeneration. Overall, the data encourage further investigations in well-defined patient cohorts to clarify the value of QSM/magnetic susceptibility in the course of neurodegenerative diseases and its potential as diagnostic biomarker.

• Authors: Solveig Tiepolt, Michael Rullmann, Thies H Jochimsen, Hermann-Josef Gertz, Matthias L Schroeter, Marianne Patt, Osama Sabri, Henryk Barthel
• Journal: European journal of radiology (Eur J Radiol) Vol. 131 Pg. 109243 (Oct 2020) ISSN: 1872-7727 [Electronic] Ireland
• PMID: 32916411 (Publication Type: Evaluation Study, Journal Article)
• Copyright: Copyright © 2020. Published by Elsevier B.V.

Chemical References

• Amyloid beta-Peptides
• Iron

Topics

• Aged
• Alzheimer Disease (metabolism, pathology)
• Amyloid beta-Peptides (metabolism)
• Brain (diagnostic imaging, metabolism, pathology)
• Evaluation Studies as Topic
• Female
• Humans
• Iron (metabolism)
• Magnetic Resonance Imaging (methods)
• Male
• Multimodal Imaging (methods)
• Positron-Emission Tomography (methods)
• Retrospective Studies