%0 Journal Article %A Asim K. Bag %A Melissa N. Wing %A Noah D. Sabin %A Scott N. Hwang %A Gregory T. Armstrong %A Yuanyuan Han %A Yimei Li %A Scott Snyder %A Giles W. Robinson %A Ibrahim Qaddoumi %A Alberto Broniscer %A John T. Lucas %A Barry L. Shulkin %T [11C]-Methionine PET for Identification of Pediatric High-Grade Glioma Recurrence %D 2021 %R 10.2967/jnumed.120.261891 %J Journal of Nuclear Medicine %P jnumed.120.261891 %X Rationale: Differentiating tumor recurrence or progression from pseudoprogression during surveillance of pediatric high-grade gliomas (PHGGs) using magnetic resonance imaging (MRI), the primary imaging modality for evaluation of brain tumors, can be challenging. The aim of this study was to evaluate whether 11C-methionine positron emission tomography ([11C]MET -PET), a molecular imaging technique that detects functionally active tumors, is useful for further evaluating MRI changes concerning for tumor recurrence during routine surveillance. Methods: We evaluated 27 lesions in 26 patients with new or worsening MRI abnormalities, where PHGG tumor recurrence was of concern during follow-up visits with [11C]MET -PET. We performed quantitative and qualitative assessments of both [11C]MET-PET and MRI data to predict the presence of tumor recurrence. Further, to assess for an association with overall survival we plotted the time from development of the imaging changes against survival. Results: Qualitative evaluation of [11C]MET-PET achieved 100% sensitivity, 60% specificity, and 93% accuracy to correctly predict the presence of tumors in 27 new or worsening MRI abnormalities. Qualitative MRI evaluation achieved sensitivity ranging from 86% to 95%, specificity ranging from 40% to 60%, and accuracy ranging from 85% to 89%. The interobserver agreement for [11C]MET-PET assessment was 100%, whereas the interobserver agreement was only 50% for MRI (P = <0.01). Quantitative MRI and [11C]MET-PET evaluation using receiver operating characteristics demonstrated higher specificity (80%) than qualitative evaluations (40-60%). Postcontrast enhancement volume, metabolic tumor volume, tumor-to-brain ratio and presence of tumor as determined by consensus MRI assessment were inversely associated with overall survival. Conclusion: [11C]MET-PET has slightly higher sensitivity, and accuracy for correctly predicting presence of tumor recurrence, with excellent interobserver agreement, than does MRI. Quantitative [11C]MET-PET can also predict overall survival. These findings suggest [11C]MET-PET can be useful for further evaluation of MRI changes during surveillance of previously treated PHGG. %U https://jnm.snmjournals.org/content/jnumed/early/2021/08/26/jnumed.120.261891.full.pdf