Study Objectives:
For central review -- to assess the agreement between local interpretation and central interpretation of the standard MRI on the 6-month progression-free survival and to estimate the accuracy of local interpretation on the 6-month progression-free survival using central review as the reference standard.
Advanced Imaging Component Objectives -- to assess the potential role of perfusion MRI and MR spectroscopy imaging as an early indicator of response to the therapy after two weeks following initiation of treatment with bevacizum and to assess the potential role of perfusion MRI and MR spectroscopy imaging as a prognostic indicator based on images taken before treatment, 2 weeks following initiation of protocol treatment, and after every 2 cycles of treatment.
Participants: Persons 18 years and older with a histologically proven intracranial glioblastoma or gliosarcoma. There must be pathologic or imaging confirmation of tumor progression or regrowth.