11C-methionine PET imaging characteristics in children with diffuse intrinsic pontine gliomas and relationship to survival

Abstract Purpose This study aimed to describe 11C-methionine (11C-MET) PET imaging characteristics in patients with paediatric diffuse intrinsic pontine glioma (DIPG) and correlate them with survival. Methods We retrospectively analysed 98 children newly diagnosed with DIPG who underwent 11C-MET PET. PET imaging characteristics evaluated included uptake intensity, uniformity, metabolic tumour volume (MTV), and total lesion methionine uptake (TLMU). The maximum, mean, and peak of the tumour-to-background ratio (TBR), calculated as the corresponding standardised uptake values (SUV) divided by the mean reference value, were also recorded. The associations between PET imaging characteristics and progression-free survival (PFS) and overall survival (OS) were assessed. Results In univariate analysis, imaging characteristics significantly associated with shorter PFS and OS included a higher uniformity grade, higher TBRs, a larger MTV, and a higher TLMU. In the multivariate analysis, larger MTV at diagnosis, shorter symptom duration, and no treatment were significantly correlated with shorter PFS and OS. Conclusion Although several imaging features were significantly associated with PFS and OS, only MTV, indicating the size of the active tumour, was identified as a strong independent prognostic factor.