Article
White matter differences in neurogenic niches in patients with GBM – a voxel-based morphometric study
Unterschiede in der weißen Substanz in neurogenen Nischen bei Patienten mit Glioblastom – eine voxel-basierte Morphometriestudie
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Published: | May 25, 2022 |
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Objective: Gliomagenesis is a highly relevant topic that has not yet been fully understood. Studies suggest that high-grade gliomas, such as GBMs, originally derive from neural precursor cells. There are two regions in the human brain containing large pools of neural stem cells, first the subventricular zone (SVZ) and second the dentate gyrus (DG) of the hippocampus. Only the SVZ has been associated with GBM development and progression. This study investigates said neurogenic niches and their involvement in GBM occurrence by means of MRI.
Methods: We examined preoperative T1-weighted, gadolinium enhanced MRI scans of 52 adult patients with histopathologically confirmed supratentorial primary GBMs. Tumor lesion masks were created for each patient and mean tissue volumes (MTV) of grey and white matter were calculated for the SVZ and the DG with the CAT12 toolbox implemented in SPM12. SVZ atlas maps were created manually with a mean thickness of approximately 2-3 mm. For the DG the preexisting CoBra hippocampal atlas was used. Patients were categorized by the smallest distance between the tumor and the regions in question, determining if the tumor had contact to either the SVZ or the DG. Interhemispheric differences were analyzed with combined and independent t-tests.
Results: MTV for white matter SVZ (p=.001), as well as for white matter DG (p<.001), were significantly higher in the tumor hemisphere than the healthy one. In the SVZ-contact group (n=10) MTV for white matter SVZ were significantly higher in the tumor hemisphere (p=.001) and in the healthy hemisphere (p=.012), than in the SVZ-non-contact group (n=35). In the DG-contact group (n=7) MTV for white matter DG were significantly higher in the tumor hemisphere (p=.001) than in the DG-non-contact group (n=38). Inverse effects were found for grey matter DG (p=.001) and total DG (p=.001), where MTV were higher in the DG-non-contact group. In the DG-contact group MTV in the healthy hemisphere were significantly higher for grey matter SVZ (p=.036) and total SVZ (p=.028).
Conclusion: For both SVZ and DG morphometric differences were found between tumor and healthy hemispheres, suggesting that especially the white matter seems to play an important role in GBM occurrence. Higher white matter mean tissue volumes were found in neurogenic regions when the tumor had contact to the SVZ or DG, indicating its significance in gliomagenesis. Additionally, DG has not yet been associated with GBM development in that way.