DSC-MRI is a special type of brain scan that uses a dynamic susceptibility contrast-enhanced magnetic resonance imaging to see how much blood is flowing through the brain. This study checks if DSC-MRI can measure blood flow changes in brain tumors called glioblastomas after treatment with a medicine called bevacizumab. Glioblastoma is a very aggressive brain cancer that often comes back after treatment. The study will see if changes in blood flow can help predict how long patients will live and how their cancer will progress. Patients will have two DSC-MRI scans, one right before starting bevacizumab and one two weeks after. The study will last up to 4 years, with check-ins every 3 months for the first year and every 6 months after that.

• Study involves two MRI scans and follow-ups for up to 4 years.
• Patients must have recurrent glioblastoma and meet specific health criteria.
• Eligible patients will receive bevacizumab treatment.