Artikel
Functional lesion-brain coupling in glioblastoma is more comparable to typical neural connectivity than in brain metastases
Die funktionelle Kopplung zwischen Läsion und Gehirn ist bei Glioblastomen eher mit der typischen neuronalen Konnektivität vergleichbar als bei Hirnmetastasen
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Veröffentlicht: | 25. Mai 2022 |
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Gliederung
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Objective: Recent investigations uncovered differences in the cellular communication between neurons and tumor cells in glioma and brain metastases. Glioma infiltration was shown to severely impact astrocyte-mediated neurovascular coupling and consequently the hemodynamic responses. Alterations of the functional hemodynamic response hence suggest distinct macroscopic differences in the overall tumor lesion-brain coupling. Our aim was to uncover differences in the functional coupling between whole-brain and the tumor lesion in patients with glioblastoma and brain metastases.
Methods: Preliminary analyses included 16 treatment-naîve patients with 8 glioblastoma (mean age: 65±4y) and 8 patients with brain metastases (58±4y). Lesions were semi-automatically segmented based contrast-enhanced T1-weighted image. Mean time series were extracted within the tumor lesion as well as mirrored to the contralesional hemisphere. Functional connectivity was computed for both seed regions of interest. The connectivity maps were subtracted to create a BOLD asynchrony map. Positive values reflect a pathological deviation from the typical global signal of the contralesional hemisphere. Mean asynchrony was computed and differences between patient groups were analyzed while controlling for tumor volume.
Results: Brain metastases depicted much higher median asynchrony values (median = 4.16, SD=12.28) than lesions in glioblastoma (0.65, SD=8.05). In glioblastoma, the overall seed-to-global connectivity was hence much more comparable to the vital contralesional brain tissue. Based on the preliminary nature of the analysis and small sample group difference did not reach statistical significance. The tumor volume did not differ significantly between glioblastoma and brain metastases (p>.05).
Conclusion: Our BOLD imaging-based evidence suggests differences in the lesion-to-global connectivity in patients with glioblastoma and brain metastases. Lesion-brain coupling in glioblastoma is overall more comparable to a typical neural signal processing. In contrast, brain metastases deviate stronger from the contralesional global connectivity signal suggesting a hemodynamic uncoupling from the typical neural communication. Larger patient studies may further uncover the electrophysiological connections underlying primary brain tumors and potentially lead to biomarkers reflecting lesion-brain coupling informing individualized treatment decisions.