Physiological uptake of 18Ffluorodeoxyglucose in the neck and upper chest region: are there predictive characteristics?

OBJECTIVE: The purpose of this study was to assess (patient) characteristics that might influence the prevalence of physiological uptake of 18Ffluorodeoxyglucose (FDG) in the neck and upper chest region (FDG NUC) in positron emission tomography (PET) imaging. METHODS: Retrospective study of static FDG PET scans in patients with malignant lymphoma, head and neck, lung or thyroid malignancy. The investigated determinants were gender, age, body mass index (BMI), tumour type, referring centre (community or university hospital), first or later PET scan, and use of benzodiazepines. RESULTS: Eighty (31%) of 260 scans showed FDG NUC. We found a strong inverse relation between age and FDG NUC (P<0.001). After adjusting for age, older head and neck tumour patients were more at risk for developing FDG NUC compared with other tumours (P=0.011). Gender, use of benzodiazepines, referring specialist, first or later PET scan or low BMI (<20 kg.m(-2)) did not influence the prevalence of FDG NUC. CONCLUSION: Multivariate logistic regression showed a strong inverse association between age and FDG NUC. No association between low BMI and FNUC could be established. In our hospital no protective effect of benzodiazepines could be determined. These data suggest that a trial designed to evaluate the efficiency of interventions to diminish FDG NUC should focus on younger patients.