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Physiological FDG uptake in the ovaries after hysterectomy.

Nishizawa S, Inubushi M, Ozawa F, Kido A, Okada H

Hamamatsu Medical Imaging Center, Hamamatsu Medical Photonics Foundation, 5000 Hirakuchi, Hamamatsu, 434-0041, Japan, sadahiko@hmp.or.jp.

OBJECTIVE: It is known that focal (18)F-fluorodeoxyglucose (FDG) uptake is physiologically seen in the ovaries and uterus of premenopausal women in correlation with the menstrual cycle, which may cause false-positive diagnoses on the images of FDG positron emission tomography (PET). The objective of this study was to clarify whether women of reproductive age after hysterectomy whose ovaries were preserved, also showed physiological ovarian FDG uptake. METHODS: We reviewed 26 women after hysterectomy (age 51.1 +/- 5.0 years), who underwent annual cancer screening, including FDG-PET and pelvic magnetic resonance (MR) imaging, three times. RESULTS: Seven women (age 45.9 +/- 5.8 years, range 34-52 years) had at least one ovary, showing changes in its appearance including the size and number of follicles on MR images each year, which suggested that the ovary was functioning. Four of the seven women showed focal FDG uptake (standardized uptake value 4.2 +/- 1.1) that corresponded to the normal ovaries on five PET examinations. Another group of 19 women (age 53.1 +/- 3.1 years, range 47-59 years) who had small ovaries without changes on MR images each year did not show FDG uptake in the ovaries. CONCLUSIONS: Physiological FDG uptake observed in the ovaries of women of reproductive age even after hysterectomy is reasonably common. As it is not easy to determine the hormonal cycle in these women, it is essential to correlate focal FDG uptake in the pelvis with anatomical and morphological findings on MR images to avoid false-positive diagnoses.

Published 20 August 2007 in Ann Nucl Med, 21(6): 345-8.
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