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Updated: May 13, 2026
Diffusion Tensor Magnetic Resonance Imaging in the Analysis of Neurodegenerative Diseases
Published on: July 28, 2013
Advanced diffusion MRI provides evidence for altered axonal microstructure and gradual peritumoral infiltration in
U Würtemberger1,2, A Rau3,4, M Diebold5
1Department of Neuroradiology, Medical Center-University of Freiburg, Faculty of Medicine, University of Freiburg, 79106, Freiburg, Germany. urs.wuertemberger@uniklinik-freiburg.de.
Purpose:
In contrast to peritumoral edema in metastases, GBM is histopathologically characterized by infiltrating tumor cells within the T2 signal alterations. We hypothesized that depending on the distance from the outline of the contrast-enhancing tumor we might reveal imaging evidence of gradual peritumoral infiltration in GBM and predominantly vasogenic edema around metastases. We thus investigated the gradual change of advanced diffusion metrics with the peritumoral zone in metastases and GBM.
Methods:
In 30 patients with GBM and 28 with brain metastases, peritumoral T2 hyperintensity was segmented in 33% partitions based on the total volume beginning at the enhancing tumor margin and divided into inner, middle and outer zones. Diffusion Tensor Imaging (DTI)-derived fractional anisotropy and mean diffusivity as well as Diffusion Microstructure Imaging (DMI)-based parameters Dax-intra, Dax-extra, V‑CSF and V-intra were employed to assess group-wise differences between inner and outer zones as well as within-group gradients between the inner and outer zones.
Results:
In metastases, fractional anisotropy and Dax-extra were significantly reduced in the inner zone compared to the outer zone (FA p = 0.01; Dax-extra p = 0.03). In GBM, we noted a reduced Dax-extra and significantly lower intraaxonal volume fraction (Dax-extra p = 0.008, V‑intra p = 0.006) accompanied by elevated axial intraaxonal diffusivity in the inner zone (p = 0.035). Between-group comparison of the outer to the inner zones revealed significantly higher gradients in metastases over GBM for FA (p = 0.04) as well as the axial diffusivity in the intra- (p = 0.02) and extraaxonal compartment (p < 0.001).
Conclusion:
Our findings provide evidence of gradual alterations within the peritumoral zone of brain tumors. These are compatible with predominant (vasogenic) edema formation in metastases, whereas our findings in GBM are in line with an axonal destructive component in the immediate peritumoral area and evidence of tumor cell infiltration with accentuation in the tumor's vicinity.
Insights
Advanced diffusion metrics reveal distinct peritumoral changes in glioblastoma (GBM) and brain metastases. GBM shows axonal damage and infiltration, while metastases exhibit vasogenic edema in the peritumoral zone.
Area of Science:
- Neuroimaging
- Oncology
- Radiology
Background:
- Glioblastoma (GBM) infiltrates surrounding brain tissue, unlike metastases which typically cause vasogenic edema.
- Histopathological differences suggest distinct peritumoral changes detectable by advanced imaging.
- Understanding these differences is crucial for accurate diagnosis and treatment planning.
Purpose of the Study:
- To investigate gradual changes in advanced diffusion metrics within the peritumoral zone of GBM and brain metastases.
- To differentiate between infiltrating tumor cells in GBM and vasogenic edema in metastases using diffusion imaging.
- To assess imaging evidence of infiltration and edema based on distance from the contrast-enhancing tumor margin.
Main Methods:
- Diffusion Tensor Imaging (DTI) and Diffusion Microstructure Imaging (DMI) parameters were analyzed in 30 GBM and 28 brain metastasis patients.
- Peritumoral T2 hyperintensity was segmented into inner, middle, and outer zones relative to the enhancing tumor margin.
- Group-wise differences and within-group gradients of diffusion metrics (FA, Dax-intra, Dax-extra, V-intra) between zones were assessed.
Main Results:
- Metastases showed reduced fractional anisotropy (FA) and Dax-extra in the inner peritumoral zone.
- GBM exhibited reduced Dax-extra and V-intra, with elevated axial intraaxonal diffusivity in the inner zone.
- Gradients between inner and outer zones were significantly higher in metastases for FA and axial diffusivity compared to GBM.
Conclusions:
- Findings suggest gradual peritumoral alterations in brain tumors.
- Results support predominant vasogenic edema in metastases.
- GBM findings indicate an axonal destructive component and tumor cell infiltration near the tumor vicinity.
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