Aim: To explore the association between SUVmax values in normal organs and major influencing factors including serum glucose level.
Materials and methods We retrospectively analyzed 523 oncological patients (age range 1-95 years old; 77 patients (14.7%) were diabetic). All patients underwent F 18-FDG PET/CT scans using a routine imaging protocol. Fasting blood glucose at time of injection, diabetic status, body mass index, uptake period, and injected dose were derived from patients' records. Fixed regions of interest were drawn at healthy organs of interest.
The study populations were divided into 2 groups depending on fasting blood glucose levels with a cut-off value of 160 mg/dl. Patients with blood glucose less than 160 mg/dl were considered as a control group. By dividing the difference in the mean SUVmax for the group with glucose ≥160 mg/dl by the mean SUVmax in the control group, the effect size was calculated using pooled SDs. Multivariate linear regression analysis was used to assess the impact of important factors affecting uptake in normal organs.
Results:
467 (89.3%) of our study population had fasting blood glucose levels less than 160 mg/dl while 56 had blood glucose ≥ 160. Only two organs (brain and muscle) showed a significant association with serum blood glucose (P <0.001, and 0.001 respectively). After adjustment of age, sex, body mass index, injected dose, and serum blood glucose; the brain continued to show a significant inverse association with fasting blood glucose (β = -1.86, P <0.001).
Conclusion
The brain was the only organ demonstrating a statistically significant association with serum blood glucose after adjustment for confounding potential values.