CT and MR Imaging Features of Adnexal Torsion

TLDR

Adnexal torsion involves twisting of the ovary or fallopian tube, causing vascular compromise that can lead to hemorrhagic infarction, often associated with ovarian cysts or neoplasms, and while ultrasound is first‑line, CT and MR imaging can also aid diagnosis. The study underscores the importance of early diagnosis to preserve the ovary. CT and MR imaging of adnexal torsion reveal fallopian tube thickening, smooth wall thickening of the twisted cystic mass, ascites, uterine deviation, and, when hemorrhagic infarction is present, eccentric thickening >10 mm and absent contrast enhancement of the mass. Specific hemorrhagic infarction signs include hemorrhage in the thickened tube, within the twisted ovarian mass, and hemoperitoneum, and early diagnosis can prevent irreversible damage and enable ovary‑sparing treatment.

Abstract

In adnexal torsion, the ovary, ipsilateral fallopian tube, or both twist with the vascular pedicle, resulting in vascular compromise. Unrelieved torsion is likely to cause hemorrhagic infarction as the degree of arterial occlusion increases. Therefore, early diagnosis is important to preserve the affected ovary. Adnexal torsion commonly accompanies an ipsilateral ovarian neoplasm or cyst but can also occur in normal ovaries, usually in children. Although ultrasonography is typically the initial emergent examination, computed tomography (CT) and magnetic resonance (MR) imaging may also be useful diagnostic tools. Common CT and MR imaging features of adnexal torsion include fallopian tube thickening, smooth wall thickening of the twisted adnexal cystic mass, ascites, and uterine deviation to the twisted side. Uncommon imaging findings in adnexal torsion that are specific to hemorrhagic infarction include hemorrhage in the thickened fallopian tube, hemorrhage within the twisted ovarian mass, and hemoperitoneum. Additional imaging findings that can suggest hemorrhagic infarction include eccentric smooth wall thickening exceeding 10 mm in a cystic ovarian mass converging on the thickened fallopian tube and lack of contrast enhancement of the internal solid component or thickened wall of the twisted ovarian mass. Early diagnosis can help prevent irreversible structural damage and may allow conservative, ovary-sparing treatment.