A Comparison of MRI Perfusion and FDG PET/CT to Distinguish Between Radiation Injury and Tumor Progression

Enhancing Brain Lesions After Radiation Therapy: A Comparison of MRI Perfusion and FDG PET/CT to Distinguish Between Radiation Injury and Tumor Progression

This study will examine if MRI perfusion and PET/CT can tell growing tumor and radiation injury apart. MRI perfusion looks at the blood vessels in the tumor. PET/CT looks if the tumor cells are actively growing. The investigators will do these two tests and see which one is better.

Patients will remain on study until the completion of either the MRI perfusion or PET/CT that are within 12 weeks of each other. After one of these scans, the patient will have no active interventions and will be off study.

Optional: Restriction Spectrum Imaging (RSI) Sequence RSI sequence is an advanced way of looking at your brain. The scan allows doctors to see how water is moving within brain tumors or within brain cells. The extra sequence takes additional 4-5 minutes in the scanner. The RSI sequence is optional. The patient will only be asked to participate if the doctor believes that it will be helpful.

Off study: Patients will remain on study until the completion of either the MRI perfusion or PET/CT that are within 12 weeks of each other. After one of these scans, the patient will have no active interventions and will be off study. Patients will obtain a standard of care brain MRI scan about every 2-3 months. These MRI scans will be used to track disease progression.

Inclusion Criteria:

• Pathological or clinical/radiological diagnosis of aneoplasm , either primary (e.g., malignant glioma) or secondary (metastasis from systemic malignancy) with a history of brain radiation therapy
• Completed fractionated radiation therapy (to 60 Gy for high grade gliomas) or stereotactic radiosurgery or hypofractionated radiation therapy (e.g. for brain metastases, anaplastic meningiomas), without or with concurrent chemotherapy
• New or increased enhancing brain lesion(s) OR nonenhancing brain lesion(s) if receiving anti-angiogenic therapy, which is considered indeterminate for tumor progression vs. radiation injury by the neuroradiologist or clinician
• Patient and/or guardian is able to provide written informed consent prior to study registration
• Age ≥ 18 years old

Exclusion Criteria:

• Claustrophobia
• Known allergic reaction to Gd-DTPA
• Any contraindication to gadolinium intravenous contrast as per standard Department of Radiology contrast guidelines
• Any contraindication to MRI (e.g., pacemaker, aneurysm clip, tissue expander).
• Pregnant or nursing female
• Unable to cooperate for MRI and/or PET/CT