Evaluation of 18FDG PET-CT in the Diagnosis of Endometriosis: A Prospective Study

Background: Noninvasive techniques have poor sensitivity and specificity in diagnosing endometriosis, which is often associated with an inflammatory process. In several benign diseases, measurement of hypermetabolism using fluorodeoxyglucose (18F18FDG) reflects the degree of inflammation and aggressiveness of the disease. This prospective study evaluated the value of 18FDG positron emission tomography (PET)-computed tomography (CT) in assessing the presence of endometriosis. Methods: Ten consecutive patients suspected with endometriosis were prospectively included in this study. A preoperative 18FDG PET-CT was performed in all the patients during the follicular phase of their cycle, which preceded laparoscopic surgery. Surgical endometriosis staging and histopathological analysis of removed tissue were confronted with the results from 18FDG PET-CT. Results: Of the 10 patients, 9 had endometriosis confirmed by laparoscopy; 6 had advanced stage of the disease and 5 had histologically proven lesions. Nevertheless, none of the patients had 18FDG-demonstrated hypermetabolism at PET-CT. Conclusions: In this preliminary series, we did not observe hypermetabolic activity in relation to endometriosis using 18FDG PET-CT. This study’s most important limitation is the use of 18FDG as an isotopic tracer, which is not specific to endometrial tissue.