Normal uptake of F-18 FDG in the testis as assessed by PET/CT in a pediatric study population

To investigate the correlation between the F-18 FDG uptake in the normal testis as assessed by PET-CT and patient age in a pediatric study population.

The study population consisted of 22 subjects aged between 9 and 17 years. For these subjects 42 PET-CT scans were available for analysis. The testis was identified on the CT images. Mean standard uptake values and testicular volume were calculated based on manually drawn regions-of-interest over the organ. The correlation between mean SUV and age as well as between testicular volume and age was calculated using Pearson's correlation coefficient.

A strong and statistically significant positive correlation between F-18 FDG uptake in the testis and age was documented. The correlation coefficient was 0.406 in the analysis based on 42 PET-CT studies (p = 0.005). The correlation between tracer uptake and age was reassessed based on 22 PET-CT studies including the last recorded PET-CT scan per patient. The correlation coefficient was 0.409 (p = 0.05). In addition, based on 22 PET-CT scans, a strong and statistically significant positive correlation between testicular volume and age was documented (r = 0.67, p < 0.001).

Whereas it was previously shown that in adult men there was a weak but statistically significant negative correlation between F-18 FDG uptake in the normal testis and age, we found a strong and statistically significant positive correlation in children and teenage boys.