CLINICAL RADIOLOGY

The Role of Magnetic Resonance Imaging and Ultrasound in Patients with Adnexal Masses

Abstract

Adoption of transvaginal ultrasound in usual clinical settings allowed us to find asymptomatic adnexal masses more frequently in postmenopausal women. These masses were traditionally considered as the indication of surgical excision to determine histological diagnosis. Recently, if the appearance of that is simple cyst, conservative management may be acceptable because ultrasound benign diagnosis is proved to be reasonably reliable. We investigate here the reliability of benign diagnosis by MR imaging with gadolinium enhancement for both of simple and complex postmenopausal adnexal cystic masses. We retrospectively examined the data of 121 postmenopausal patients who underwent surgery during a 3-years-period (from January, 2000 to December 2002) for adnexal mass under diagnosis of benign adnexal cysts based on MR imaging.

The Role of Magnetic Resonance Imaging and Ultrasound in Patients with Adnexal Masses

Introduction

Postmenopausal adnexal mass has long been considered as an indication for surgical exploration in order to exclude malignancy. Recently, the increasingly frequent use of transvaginal ultrasonography allows us to diagnose incidental, asymptomatic adnexal masses more frequently than earlier times in postmenopausal women. Most postmenopausal ovarian unilocular cystic masses, with neither thickening of the wall nor mural nodule as determined by ultrasonographic observation, prove to be benign after histological assessment. (Horiuchi et al, 2003, 309-331) The postmenopausal cystic adnexal mass: the potential role of ultrasound in conservative management, Obstet Gynecol 73 (1989), pp. 8-10.

Moreover, it is reported that more than 60% of adnexal unilocular masses diagnosed by transvaginal ultrasonography were regressed spontaneously during careful follow-up program. Therefore, conservative management of ovarian cysts has been allowed if imaging analysis, usually performed by ultrasonography, showed an unilocular echo-free, i.e., a simple cystic pattern with thin smooth wall. However, Ekerhovd et al. (2001, 48-54) reported that 1.6% of simple unilocular cysts diagnosed by transvaginal ultrasonography in postmenopausal women were proved to be borderline or malignant after surgery. For ovarian cysts with complex patterns such as echogenic cyst content, solid parts or papillary formation determined by ultrasonography, a malignancy rate of 8-10% was reported. Therefore, complex adnexal masses determined by transvaginal ultrasonography were considered as indication for surgery still now. (Kurjak et al, 2002, 245-254)

Magnetic resonance (MR) imaging is generally preferred for further testing rather than computed tomography when the results of ultrasonography are inconclusive. In cases in which complex patterns are seen by ultrasonography, comparison of T1-weighted images from contrast-enhanced MR imaging with T1- and T2 weighted images could be a useful tool for diagnosing the malignancy of ovarian tumors. If the MR imaging diagnosis of “benign” adnexal mass even for masses showing a complex pattern is as reliable as the ultrasonographic diagnosis of “benign” simple cysts, careful conservative management for complex ovarian cysts would also be an acceptable strategy to prevent unnecessary surgical intervention. (Kurtz et al, 1999, 19-27) In this study, we retrospectively evaluated post-menopausal adnexal mass diagnosed as benign by MR imaging with postoperative histopathological findings. We revealed that the reliability of the preoperative benign diagnosis by MR ...