This study is for subjects with a diagnosis of a brain tumor called glioblastoma that is being treated with bevacizumab. This study will use a new MRI technique to compare the images of blood vessels and tumor structure to the effectiveness of bevacizumab.

This study is for subjects with a diagnosis of a brain tumor called glioblastoma that is being treated with bevacizumab. Bevacizumab is a drug that your doctor believes is the best treatment option available to subjects at this time for this type of tumor. Bevacizumab affects the growth of blood vessels by tumors such as glioblastoma, thus effectively starving the tumor of oxygen and food.

Magnetic Resonance Imaging (MRI) is a test done by a machine in the radiology department that takes pictures of your body using special magnets, rather than X-rays. With a new MRI scan technique the investigators can take very, very detailed images of the vessel and tumor structure. This project will allow us to compare the images of vessel and tumor structure to the effectiveness of Bevacizumab as a treatment option. With this project the investigators will hopefully develop an accurate way to predict whether or not Bevacizumab will be an effective treatment option for patients.

Inclusion Criteria:

• Age between 18 and 80 years of age
• Progressive glioblastoma patients who have been planned to receive bevacizumab
• Karnofsky Performance Status 50 or above (vd. Appendix A)
• Established pathologic diagnosis of glioblastoma
• Prior treatment with radiation and chemotherapy
• Neuroimaging progression of glioblastoma
• Able and willing to provide informed consent (or consent of a guardian)

Exclusion Criteria:

• Contraindication to MRI
• Contraindication to bevacizumab therapy
• Concurrent enrollment in other neuroimaging trials
• Prior therapy with bevacizumab
• Known hypersensitivity to MRI contrast
• Females who are nursing or pregnant

Male and female subjects, 18-80 years old with progressive glioblastoma who receive bevacizumab