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

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.

The study will prospectively enroll patients who have increasing size and/or enhancement of brain lesion(s) after brain radiation therapy for a neoplasm (either primary or metastatic), where. it is unclear if a lesion represents radiation injury or progressive tumor. At the discretion of PI the RSI sequence may be repeated at SOC FDG or other radiotracer imaging carried out while the patient is still on study, if deemed clinically necessary.

The MRI perfusion and PET/CT scans will be obtained within 12 weeks of each other. These scans are part of the standard of care for patients with brain tumors and uncertain tumor response or progression after treatment. Although every effort will be made to perform both MRI perfusion and PET/CT on the same day or during the same week, some patients may experience longer intervals between scans due to scheduling conflicts. The disease in question (radiation injury vs. tumor progression) may change slightly during this interval (e.g., the lesion may grow or shrink slightly), but no large changes are expected between the two scans. The patients may continue existing treatments in the interval between scans (e.g., steroids, chemotherapy), but the two scans must be performed before any change or new treatment occurs. Fusion images of MRI and PET/CT will not be reviewed by the neuroradiologist interpreting the MRI perfusion nor the nuclear medicine radiologist interpreting the PET/CT.

To assess the utility of PET/CT and MRI perfusion studies in predicting whether worsening enhancing brain lesions seen after radiation therapy represent radiation injury or tumor progression. This study will examine the role of these two imaging techniques in predicting diagnosis and treatment planning.

To assess the utility of PET and MRI perfusion studies in predicting tumor progression in patients with tumors with a history of brain radiation therapy receiving anti-angiogenic therapy (such as bevacizumab).

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