Value of intra-adnexal and extra-adnexal computed tomographic imaging features diagnosing torsion of adnexal tumor.

OBJECTIVE: The objective of this study was to evaluate the usefulness of the intra-adnexal and extra-adnexal computed tomographic (CT) features in identifying adnexal torsion.

PATIENTS AND METHODS: We retrospectively analyzed CT examinations of 38 adnexal masses with torsion and 270 without torsion, which has been surgicopathologically confirmed. The CT features were evaluated according to 2 categorized groups. The first group included the intra-adnexal features dealing with the ovary and uterine tube, whereas the other included the extra-adnexal features dealing with changes of adjacent anatomical structures such as the uterus, gonadal vein, and peritumoral zone. We acquired statistical proportions for the frequencies of these 2 groups of CT features in ovarian tumors with adnexal torsion versus those without adnexal torsion.

RESULTS: When there were intra-adnexal CT features of adnexal torsion, peculiar uterine tube thickening was identified in 74% of the lesions, eccentric or concentric wall thickening in 54% (of only cystic lesions), eccentric septal thickening in 50% (of only cystic lesions except mature cystic teratoma), and eccentric or diffuse decreased or poor contrast enhancement of the internal solid component or thickened wall in 50%. In extra-adnexal CT features of adnexal torsion, uterine deviation to the twisted side was identified in 61% of the lesions, peritumoral infiltration in 40%, nonvisualized anatomic continuity of the ipsilateral gonadal vein with the twisted adnexal mass in 71%, and ascites in 13%. There were significant differences in all of the intra-adnexal and extra-adnexal CT findings, except for ascites, between twisted and nontwisted adnexal tumors.

CONCLUSIONS: The intra-adnexal and extra-adnexal groups of CT features are valuable in identifying torsion of adnexal mass.