Related Experiment Video
Updated: Mar 27, 2026
08:16
High-resolution Structural Magnetic Resonance Imaging of the Human Subcortex In Vivo and Postmortem
Published on: December 30, 2015
15.9K
Assessing Age-Associated Influences on Paramagnetic and Diamagnetic Susceptibility Maps in Postmortem Human Brains
José Henrique Monteiro de Azevedo1,2, Maria Concepción Garcia Otaduy3, Andre Avanzine1
1InBrain, Department of Physics, FFCLRP, University of São Paulo, Ribeirão Preto, Brazil.
NMR in Biomedicine
|March 26, 2026
Summary
Magnetic susceptibility mapping in postmortem brain MRI reveals age-related changes in iron and myelin. Diamagnetic susceptibility declines with age in deep gray matter, while paramagnetic susceptibility increases in the putamen, correlating with iron levels.
Area of Science:
- Neuroimaging
- Biomarkers of Aging
- Neurodegenerative Diseases
Background:
- Magnetic susceptibility mapping offers insights into brain iron and myelin distribution during aging.
- Postmortem validation is crucial for ensuring in vivo MRI maps accurately reflect biological processes.
- Understanding age-related changes in magnetic susceptibility aids in interpreting neuroimaging data for aging and disease.
Purpose of the Study:
- To investigate age-related alterations in paramagnetic and diamagnetic magnetic susceptibility components using postmortem MRI.
- To compare in situ postmortem findings with previously reported in vivo associations.
- To explore the relationship between myelin integrity and diamagnetic susceptibility, and iron concentration with paramagnetic susceptibility.
Main Methods:
- Applied the APART-QSM method for susceptibility separation to postmortem MRI data from 47 subjects (ages 31-91).
- Utilized linear regression to assess age-related susceptibility changes in 17 deep gray matter (DGM) and white matter (WM) regions.
- Correlated fractional anisotropy (FA) with diamagnetic susceptibility in WM, and analyzed ex vivo putamen tissue for iron concentration.
Main Results:
- Diamagnetic susceptibility showed a consistent age-related decline in DGM basal ganglia.
- A negative correlation between FA and diamagnetic susceptibility in WM suggested myelin contribution.
- Putamen paramagnetic and total QSM susceptibility increased linearly with age, correlating with iron concentration.
Conclusions:
- Postmortem magnetic susceptibility mapping enhances biological interpretability of MRI data in aging.
- Findings support iron's contribution to paramagnetic susceptibility in the putamen and myelin's role in diamagnetic susceptibility.
- Promotes cross-validation between imaging and tissue analysis, with implications for aging and neurodegenerative disease research.
More Related Videos
Related Concept Videos
01:31Magnetic Susceptibility and Permeability
2.7K
In linear magnetic materials, like paramagnets and diamagnets, magnetization is proportional to the magnetic field intensity. The constant of proportionality, a dimensionless number, is called magnetic susceptibility. The value of the susceptibility depends on the type of material.
When diamagnetic materials are placed under an external magnetic field, the moments opposite to the field are induced. Hence, the susceptibility for diamagnets has a minimal negative value of 10-5–10-6. Since...
When diamagnetic materials are placed under an external magnetic field, the moments opposite to the field are induced. Hence, the susceptibility for diamagnets has a minimal negative value of 10-5–10-6. Since...
2.7K
01:24Magnetic Resonance Imaging
10.3K
Magnetic resonance imaging (MRI) is a noninvasive medical imaging technique based on a phenomenon of nuclear physics discovered in the 1930s, in which matter exposed to magnetic fields and radio waves was found to emit radio signals. In 1970, a physician and researcher named Raymond Damadian noticed that malignant (cancerous) tissue gave off different signals than normal body tissue. He applied for a patent for the first MRI scanning device in clinical use by the early 1980s. The early MRI...
10.3K
01:26Diamagnetism
3.4K
Materials consisting of paired electrons have zero net magnetic moments. However, when these materials are placed under an external magnetic field, the moments opposite to the field are induced. Such materials are called diamagnets. Diamagnetism is the response of the diamagnets when placed in an external magnetic field.
Diamagnetism was discovered by Anton Brugmans in 1778 when he observed that bismuth gets repelled by magnetic fields, thus theorizing that diamagnets get repelled by magnets....
Diamagnetism was discovered by Anton Brugmans in 1778 when he observed that bismuth gets repelled by magnetic fields, thus theorizing that diamagnets get repelled by magnets....
3.4K