Imaging of Adnexal Torsion

Abstract

While sudden onset of severe pelvic pain in an afebrile woman of reproductive age is considered the classic presentation of a patient with adnexal torsion, this constellation of findings occurs in the minority of patients with adnexal torsion. In fact, many patients with adnexal torsion present with mild or intermittent symptoms and adnexal torsion likely occurs more frequently than originally thought in post menopausal women. Thus, the clinical presentation is often non-specific and may mimic other gynecologic pathology and even renal or gastrointestinal causes of lower quadrant pain. Duplex Doppler ultrasound (US) is typically the initial imaging study performed in female patients with suspected gynecological pathology. Findings of an enlarged amorphous, heterogenous ovary with an underlying mass or peripheral small follicles in an abnormal midline location are suggestive of ovarian torsion on ultrasound examination. Color Doppler interrogation may demonstrate the twisted blood vessels in the adnexal pedicle. Absence of Doppler detected blood flow suggest torsion and/or infarction but the documentation of blood flow should not exclude the diagnosis of torsion in a painful ovary with suspicious morphologic features. Since computed tomography (CT) may be the first imaging study obtained in patients suspected of harboring gastrointestinal or renal pathology, the radiologist should be familiar with the CT findings or ovarian torsion such as the presence of an enlarged, non-enhancing midline ovary/mass with an adjacent thickened or beak shaped tube or hematoma. Magnetic resonance imaging (MRI) has a role in the work-up of pelvic pain when CT or US findings are non-specific. Findings of adnexal torsion on MR are similar to findings observed on CT. However, the presence of high signal intensity stromal edema and numerous peripheral foillicles as well as lack of stromal enhancement are more easily detected on MRI.