Ovarian torsion: CT and MR imaging appearances.

PURPOSE: To describe the features of twisted ovarian tumors on computed tomographic (CT) scans and magnetic resonance (MR) images.

MATERIALS AND METHODS: The CT scans, MR images, clinical records, and histopathologic findings in 10 patients with surgical proof of a twisted adnexal tumor were retrospectively evaluated.

RESULTS: The most common findings on MR images were nonspecific: deviation of the uterus to the twisted side (n = 9), engorged blood vessels on the twisted side (n = 6), a small amount of ascites (n = 5), and obliteration of fat (n = 4). The following characteristics were seen only in the five patients with hemorrhagic infarction: (a) a protrusion of the lesion on the twisted side to which the uterus was continuous or engorged blood vessels converged (n = 5); (b) thick, straight blood vessels that draped around the lesion (n = 2); (c) distinct hematoma (n = 2); and (d) complete absence of enhancement (n = 3).

CONCLUSION: Three findings (a, b, and d) seem to be diagnostic of the twisted adnexal tumor and may facilitate prompt surgical intervention at examination with MR imaging or CT.