MRI with Susceptibility Weighted Image (SWI) In Preoperative Evaluation Of Patients With Suspected Pelvic Endometriosis

Abstract

ndometriosis is a common disease in women of reproductive age and is defined as the presence of endometrial tissue outside of the uterine cavity. Endometriomas occur when ectopic endometrial tissue implants enlarge and repeatedly hemorrhage in response to hormonal stimulation, forming cystic lesions commonly on the ovaries. Although ultrasonography (US) is the first-line imaging modality in the evaluation of adnexal masses, magnetic resonance (MR) imaging has been shown to have higher specificity than US for diagnosis of endometriomas. Endometriomas with typical MR manifestations are easily diagnosed on routine MR examination. “T2 shading” was actually the classic MR feature of an endometrioma and is defined as a cystic lesion with hyperintense signal on a T1-weighted image that demonstrates T2 shortening resulting in relative hypointensity on T2-weighted images. This is thought to occur secondary to the high concentration of protein and degraded blood products that result from the repeated hemorrhage. This sign was initially reported to have very high specificity (96%) for endometriomas. However, T2 shading can be seen in other hemorrhagic adnexal lesions, namely hemorrhagic cysts.