(¹⁸F-FET-PET) in the pediatric population for characterization of brain gliomas.

Background: To identify the correlation between data derived from image analysis of ¹⁸F-FET-PET imaging and histopathology findings on gross specimens in the grading of paediatric brain gliomas.

Methods: We identified all paediatric patients (N=20) with brain gliomas who had undergone both ¹⁸F-FET-PET imaging and histopathology analysis of a gross specimen since the installation of the RCH PETMRI scanner in 2016. From stored imaging analysis we reconfirmed and re-analysed for SUVmax, tumour to brain ratio (TBR) and tumour activity curves (TAC). WHO grading (WHO I-IV) and Ki67 index percentages were noted from existing histopathology reports in patient files.

Results: Specificity of SUVmax values (SUV>4) for a high-grade lesion were found to be 71% (specificity 33%)Accuracy was calculated at 80%. TBR (TBR>2) sensitivity for a high-grade glioma was 86% (Accuracy 70%). There was overall positive trend noted between increasing SUVmax and TBR values when compared to WHO grading. There was no correlation between assumed severity of the lesions based on TAC curves when compared to the WHO grading of the gross specimen.

Conclusions: ¹⁸F-FET-PET is an accurate tool for identifying brain gliomas in the paediatric population. SUVmax and TBR values appear to be useful predictors of glioma severity, similar to findings of studies in adult populations. The role of TAC curves in the prognostication of gliomas for the studied population was unclear. The study was limited by a small patient size and the use of ¹⁸F-FET-PET in the paediatric glioma population requires further investigation with a larger patient pool.