Physiological FDG uptake in growth plate on pediatric PET.

Abstract

18F-Fluorodeoxyglucose (FDG) uptake in children is different from that in adults. Physiological accumulation is known to occur in growth plates, but the pattern of distribution has not been fully investigated. Our aim was to evaluate the metabolic activity of growth plates according to age and location. We retrospectively evaluated 89 PET/CT scans in 63 pediatric patients (male : female=25 : 38, range, 0-18 years). Patients were classified into four age groups (Group A: 0-2 years, Group B: 3-9 years, Group C: 10-14 years and Group D: 15-18 years). The maximum standardized uptake value (SUVmax) of the proximal and distal growth plates of the humerus, the forearm bones and the femur were measured. The SUVmax of each site and each age group were compared and statistically analyzed. We also examined the correlations between age and SUVmax. As for the comparison of SUVmax in each location, the SUVmax was significantly higher in the distal femur than those in the other sites (p< 0.01). SUVmax in the distal humerus and the proximal forearm bones were significantly lower than those in the other sites (p< 0.01). In the distal femur, there was large variation in SUVmax, while in the distal humerus and the proximal forearm bones, there was small variation. As for the comparison of SUVmax in each age group, the SUVmax in group D tended to be lower than those in the other groups, but in the distal femur, there was no significant difference among each age group. Our data indicate that FDG uptake in growth plates varies depending on the site and age with remarkable uptake especially in the distal femur.