Characterizing Hemodynamic Alterations in Glioma: Insights From Resting-State Functional MRI.

BACKGROUND AND PURPOSE

This study aims to characterize hemodynamic alterations in gliomas by analyzing global signal metrics and amplitude of low-frequency fluctuations (ALFF).

METHODS

We analyzed resting-state functional MRI data from an open dataset. A total of 29 glioma patients (17 men; mean age: 44.2 ± 13.9 years; 16 high-grade) were included. Global signal cross-correlation (GSXC), representing the maximum cross-correlation value between each voxel's time series and the average gray matter signal of the contralateral hemisphere, and ALFF were calculated. Regions of interest for tumor were defined and mirrored to the contralateral side for comparison. Linear mixed-effects models were used to examine effects of tumor grade and measurement side on GSXC and ALFF. Post hoc analyses compared tumor versus contralateral regions.

RESULTS

GSXC was significantly reduced in tumor regions compared to the contralateral hemisphere, regardless of tumor grade (low-grade: 0.31 ± 0.21 vs. 0.45 ± 0.16, p = 0.005; high-grade: 0.39 ± 0.17 vs. 0.55 ± 0.13, p < 0.001). ALFF was significantly lower in low-grade tumors compared to the contralateral side (0.65 ± 0.15 vs. 0.77 ± 0.14, p = 0.005), while no significant difference was found in high-grade tumors (0.80 ± 0.18 vs. 0.77 ± 0.10, p = 0.46).

CONCLUSIONS

Our findings suggest that GSXC and ALFF provide complementary pathological information on glioma. GSXC indicates impaired cerebrovascular reactivity due to gliovascular uncoupling, whereas ALFF shows an increase in high-grade gliomas likely reflecting greater total vascularity.