What is adnexal torsion, and what are its CT and MRI features?
Adnexal torsion occurs when the adnexa and its vascular pedicle twist, resulting in ischemic injury to the ovary and/or fallopian tube. In the majority of cases, a predisposing functional cyst or neoplasm (most commonly a mature teratoma) is present. Treatment with urgent adnexal detorsion and oophoropexy is performed to prevent adnexal infarction when possible, along with removal of predisposing adnexal lesions when present. Otherwise, oophorectomy or salpingo-oophorectomy may be necessary.
On CT and MRI, an adnexal mass, ovarian enlargement, and simple or hemorrhagic pelvic fluid are commonly visualized. Other imaging findings include decreased or absent ovarian enhancement; ovarian stromal edema with peripheral follicles; visualization of a twisted vascular pedicle; fallopian tube wall thickening; ipsilateral uterine deviation; atypical location of the adnexa to the contralateral pelvis or midline; adnexal fat stranding; or hemorrhage within the ovary or fallopian tube.
