Purpose: Good knowledge of physiological 18F-fluorodeoxglucose (18F-FDG) uptake in the healthy population is of great importance for the correct interpretation of 18F-FDG positron emission tomography (PET) images of pathological processes. The purpose of this study was to investigate the physiological 18F-FDG uptake in the ovaries and uterus of healthy female volunteers.
Methods: One hundred and 33 healthy females, 78 of whom were premenopausal (age 37.2+/-6.9 years) and 55 postmenopausal (age 55.0+/-2.7 years), were examined using whole-body 18F-FDG PET and pelvic magnetic resonance (MR) imaging. Focal 18F-FDG uptake in the ovaries and uterus was evaluated visually and using standardised uptake value (SUVs). Anatomical and morphological information was obtained from MR images.
Results: Distinct ovarian 18F-FDG uptake with an SUV of 3.9+/-0.7 was observed in 26 premenopausal women out of 32 examined during the late follicular to early luteal phase of the menstrual cycle. Eighteen of the 32 women also showed focal 18F-FDG uptake in the endometrium, with an SUV of 3.3+/-0.3. On the other hand, all nine women in the first 3 days of the menstrual cycle demonstrated intense 18F-FDG uptake in the endometrium, with an SUV of 4.6+/-1.0. No physiological 18F-FDG uptake was observed in the ovaries or uterus of any postmenopausal women.
Conclusion: In women of reproductive age, 18F-FDG imaging should preferably be done within a week before or a few days after the menstrual flow phase to avoid any misinterpretation of pelvic 18F-FDG PET images.