Susceptibility-weighted MR sequence for the evaluation of ovarian masses with torsion

Abstract

Adnexal torsion is a rare gynecologic emergency caused by twisting of an adnexal mass. Twisted vascular pedicle is the most specific imaging finding for adnexal torsion, however, identification of twisted vascular pedicle can be challenging. The purpose of this study is to evaluate the feasibility of susceptibility-weighted magnetic resonance (MR) sequence (SWS) for the diagnosis of adnexal torsion. MR imaging including SWS (SWAN: Susceptibility-weighted angiography) of surgically proven four benign ovarian masses with torsion (one acute and three subacute to chronic torsions) were retrospectively evaluated. Three cystic masses and one solid mass were included in this study. High signal intensity venous thrombus within the twisted vascular pedicle on T₁-weighted imaging (T1WI) was detected in three lesions with subacute to chronic torsion (75%) but not in one lesion with acute torsion, whereas susceptibility-induced signal voids within the twisted vascular pedicle on SWAN were detected in all four lesions (100%). The demonstration of venous thrombus in the twisted vascular pedicle by SWS may be diagnostic for adnexal torsion. SWS can detect blood products sensitively and can reveal venous thrombus in the twisted vascular pedicle, which may be helpful for the diagnosis of adnexal torsion.