Diagnostic value of additional 18F-FDG PET/CT imaging using a vaginal catheter in patients with paravaginal malignant lesions.

BACKGROUND: In routine noncontrast-enhanced PET/computed tomography (CT) studies, the female pelvis is one of the most challenging anatomical regions to interpret. In surgically treated patients, it may be more difficult to determine the accurate location of paravaginal hypermetabolic lesions. In this study, the aim was to investigate the contribution of additional PET/CT imaging using a vaginal catheter in patients with pelvic malignant disease. METHODS: Forty-seven patients with pelvic malignancies were enrolled in this study. Following routine whole-body fluorine-18 fluorodeoxyglucose (F-FDG) PET/CT scanning, an additional pelvic scan was obtained after placement of a plastic catheter in the vaginal lumen (v-catheter). All suspected foci in vaginal and paravaginal areas were evaluated for both studies. The contribution of additional v-catheter imaging was determined visually by five experienced interpreters. RESULTS: Pathological F-FDG uptake in various vaginal and/or paravaginal locations was detected in 24 of 47 patients after conventional PET/CT imaging. In 10 of these 24 patients, anatomic relations within the uptake area could not be confidently described and v-catheter imaging provided a significant contribution in all 10 cases. In seven of these 10 sites examined, pathological F-FDG uptake was safely ruled out and three sites were confirmed to be malignant. In total, the final interpretation in 13 of 24 patients (54%) was modified by additional v-catheter imaging. The contribution rate of catheter imaging was 89% in treated patients and 33% in untreated patients with vaginal and/or paravaginal lesions on initial scans. CONCLUSIONS: Additional v-catheter imaging of pelvis may be of diagnostic value in the accurate anatomical definition of hypermetabolic lesions in the vaginal/paravaginal area on noncontrasted PET/CT studies.