Novel Magnetic Resonance Imaging and Positron Emission Tomography in the RT Planning and Assessment of Response of Malignant Gliomas

Current strategies for treatment and management of gliomas incorporate molecular markers to individualize patient care. Physiologic imaging including magnetic resonance (MR) and positron emission tomography (PET) identify treatment-associated alterations in tissue properties including cellular viability, vascular function, and molecular response. MR and PET imaging biomarkers provide a noninvasive approach for early treatment response assessment and a powerful tool to individualize patient management. Gliomas are heterogenous tumors. Parametric response mapping (PRM) is a novel voxel-wise imaging analysis method which directly addresses the issue of tumor heterogeneity. PRM imaging analysis improves the predictive accuracy of the imaging biomarkers in clinical applications including individualized radiation treatment planning and treatment response assessment. A multiparametric (MP) imaging biomarker derived from MR perfusion, diffusion-weighted imaging (DWI), and fluid attenuated inversion recovery (FLAIR) using a PRM analysis method provides biologic target volumes necessary to direct the localization of stereotactic biopsy, presurgical planning for glioma resection, and treatment planning for radiation therapy (RT). Validation of PRM-derived imaging biomarkers in multi-institutional clinical trials is necessary prior to their routine clinical application in the management of gliomas.