Amino acid PET-MRI of malignant gliomas for biopsy planning

Abstract

Accurate determination of the border and grade of malignant gliomas is critical to patient management. Contrast-enhancing areas in MRI sequences of malignant gliomas are a target for biopsy, surgery, and radiation therapy, but there can be discrepancies between these areas and the actual extent of tumor. Here we prospectively collected over 400 serial biopsy specimens from 23 patients with contrast-enhancing high-grade gliomas using hybrid PET-MRI sequences to assess the utility of this imaging approach for obtaining accurate biopsies. In 35% cases, the biopsy result was changed to a higher tumor grade after the inclusion of FET-positive sites. In all cases, high FET uptake was visualized and confirmed outside areas of contrast enhancement on MRI, indicative of high-grade glioma. FET-PET can therefore be used to locate the most malignant areas of contrast-enhancing gliomas, thereby impacting consequent management.