TY - JOUR T1 - <strong>18F-FET-PET/MR-guided biopsies of contrast-enhancing gliomas: a prospective study</strong> JF - Journal of Nuclear Medicine JO - J Nucl Med SP - 3115 LP - 3115 VL - 63 IS - supplement 2 AU - Maciej Harat AU - Bogdan Malkowski AU - Józefina Rakowska AU - Marek Harat AU - Iza Miechowicz AU - Jacek Furtak AU - Lukasz Szylberg Y1 - 2022/06/01 UR - http://jnm.snmjournals.org/content/63/supplement_2/3115.abstract N2 - 3115 Introduction: MRi- guided stereotactic biopsy is a gold standard for diagnosis of unresectable high grade glioma. A&amp;nbsp;prospective study was planned to assessed whether PET-guided biopsies were more accurate than MRI-based. Also to examine the value of early FET-PET acquisition for the identification of high grade foci not associated with contrast enhancement.Methods: Twenty-three patients were enrolled in this study due to suspected high grade glioma. Patients meeting the inclusion criteria were referred for dual time point&amp;nbsp;18F-FET PET-MRI. &amp;nbsp;Biopsies were planned based on early FET-PET acquisition 5-15 minutes post tracer injection. The following biopsy sites were determined in each case: (i) site of contrast enhancement and increased FET uptake (ii) contrast enhancement but no increase in FET uptake; (iii) increased FET uptake but without contrast enhancement; and (iv) peripheral areas hyperintense in T2 FLAIR without increased FET uptake and contrast enhancement.&amp;nbsp;Results: 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. Results from biopsies based on the FLAIR sequences corresponded to neoplastic lesions in 13 cases (57%), most often with a lower grade than in areas of high FET uptakeConclusions: Early FET-PET can be used to locate the most malignant areas of contrast enhancing gliomas. Treatment or biopsy planning based solely on MRI images may miss some areas of glioma. Brain areas hyperintense in T2 FLAIR are not specific for malignancy. ER -