The Mechanism Causing High-signal Intensity on Diffusion-weighted Imaging in Adnexal Torsion: Two Case Reports

Clinical Utility of Diffusion-Weighted Imaging in Gynecological Imaging: Revisited

ABSTRACT

Diffusion-weighted imaging (DWI) is an increasingly valuable sequence in daily clinical practice, providing both functional and morphological information. The use of DWI can help quantify diffusion using the apparent diffusion coefficient, which reflects the physiological features of the tissue and tumor microcirculation. This knowledge is crucial for understanding and interpreting gynecological imaging. This article reviews the clinical utility of DWI for gynecological imaging, highlighting its ability to aid in the detection of endometrial and cervical cancers, as well as tumor extension and metastasis. In addition, DWI can easily detect the solid components of ovarian cancer (including dissemination), assist in the diagnosis of adnexal torsion, and potentially show bone marrow status. Apparent diffusion coefficient measurement is useful for differentiating between endometrial lesions, uterine leiomyomas, and sarcomas, and may provide important information for predicting the prognosis of gynecological cancers.

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

OBJECTIVE

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 MR sequence (SWS) for the diagnosis of adnexal torsion.

METHODS

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.

RESULTS

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%).

CONCLUSION

The demonstration of venous thrombus in the twisted vascular pedicle by SWS may be diagnostic for adnexal torsion.

ADVANCES IN KNOWLEDGE

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.