Imaging of gynecologic malignancies with FDG PET-CT: case examples, physiologic activity, and pitfalls

The utilization of 2-[fluorine 18] fluoro-2-deoxy-D-glucose (FDG) positron emission tomography (PET) in combination with computed tomography (CT) in the assessment of gynecologic malignancies has been rapidly growing in recent years; however, its role in clinical practice has yet to be established. A number of pitfalls are commonly encountered, including normal physiologic activity in bowel loops and blood vessels, or focal retained activity in ureters and urinary bladder. Increased uptake has also been reported in many benign pelvic processes and in premenopausal patients; endometrial activity changes cyclically, whereas increased ovarian uptake may be functional. FDG PET-CT has an emerging role in staging nodal disease and in the evaluation of local recurrence or peritoneal spread of gynecologic malignancies and is also useful in monitoring response to therapy and in long-term follow-up. FDG PET-CT is most suitable in patients with high tumor markers and negative or uncertain conventional imaging data. Patient preparation, proper scanning protocol, combined assessment of PET and CT data, and the evaluation of conventional imaging findings are essential to define disease and to avoid diagnostic pitfalls.