¹⁸ F-FDG PET standard uptake values of the normal pons in children: establishing a reference value for diffuse intrinsic pontine glioma

Abstract

Background

Positron emission tomography (PET) scanning with [ ¹⁸ F]fluorodeoxyglucose ( ¹⁸ F-FDG) is a useful diagnostic and prediction tool in brain tumors, but its value in childhood diffuse intrinsic pontine glioma (DIPG) is still unclear. For interpretation of ¹⁸ F-FDG PET results in DIPG, uptake values of the normal pons of children of increasing ages are mandatory. The aim of this study was to determine ¹⁸ F-FDG standard uptake value ratios (SUVr) of the normal pons and to compare these to those of DIPG.

Methods

We studied 36 subjects with a normal, non-affected pons (aged 5 to 23 years) and 6 patients with DIPG (aged 4 to 17 years) who underwent ¹⁸ F-FDG PET scanning. Magnetic resonance imaging (MRI) was co-registered to define the regions of interest. SUVr and SUVrmax for the pons/cerebellum (SUVr _p/c) and the pons/occipital lobe (SUVr _p/o) were calculated. Independent-samples t tests and Mann–Whitney U tests were used to compare the mean SUVr and Pearson’s test for correlations.

Results

For the normal pons, mean SUVr _p/c and SUVr _p/o were 0.65 (±0.054) and 0.51 (±0.056), respectively. No significant correlations were found between the SUVr of the normal pons and sex, age, nor pontine volume. A modest but statistically significant correlation was found between SUVr and post-injection time acquisition timing. For DIPG, mean SUVr _p/c and SUVr _p/o were 0.74 (±0.20) and 0.65 (±0.30), respectively, while mean SUVr _p(max)/c and SUVr _p(max)/o were 1.95 (±0.48) and 1.81 (±0.20), respectively.

Conclusion

The SUVr of the unaffected pons are strikingly constant between children, irrespective of sex and age, and can therefore be well used as a reference value for ¹⁸ F-FDG PET studies in DIPG.