Endometriosis: the role of magnetic resonance imaging.

Several imaging options are available today to diagnose endometriosis. Currently, the two techniques most used are sonography and magnetic resonance imaging (MRI). Three-dimensional (3D) sonography has proved to be particularly sensitive in the diagnosis of endometriosis. In recent years, MRI has emerged as a high reproducible method to explore endometriosis; moreover, its capability to evaluate tissue signal is an extremely powerful system in the differential diagnosis with other pathologies and for the identification of malignant degeneration. The purpose of this paper is to present the state-of-the-art of MRI of endometriosis by performing a review of the literature and showing the epidemiology, pathogenesis, and classification of endometriosis. In this work, the technique that should be used, MR findings of endometriosis and the principles of differential diagnosis are explained.

Diagnostic confidence analysis in the magnetic resonance imaging of ovarian and deep endometriosis: comparison with surgical results.

OBJECTIVE: To assess the diagnostic confidence of multiple readers in the magnetic resonance imaging (MRI) diagnosis of endometriosis. METHODS: Sixty-five patients (mean age 33; range 19-45 years) who had undergone MRI were retrospectively evaluated. Five regions were analysed and the presence of endometriosis was scored on a five-point scale in order to assess the diagnostic confidence. Statistical analysis included receiver operating characteristic (ROC) curve analysis, the Cohen weighted test and sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), accuracy, positive likelihood ratio (LR+) and negative likelihood ratio (LR-). RESULTS: The areas under the curve (AUC) in the detection of ovarian endometrioma were 0.942, 0.893 and 0.883 for readers 1, 2 and 3, respectively; in the uterosacral ligament (USL) AUCs were 0.907, 0.804 and 0.842; in the vaginal fornix (VF) 0.819, 0.733 and 0.69; in the anterior compartment 0.916, 0.833 and 0.873; and in the rectum/sigma/pouch of Douglas (RSD) 0.936, 0.856 and 0.834. CONCLUSIONS: Diagnostic confidence of the observers is different according to the region of the nodules of endometriosis and it can be challenging in the VF and for the less experience readers also in the AC and RSD. Moreover the degree of uncertain diagnosis for the less expert readers may reach up to one third of the examinations. KEY POINTS: • Magnetic resonance imaging (MRI) is increasingly used to assess endometriosis • The diagnostic confidence of observers varies according to the location of endometriosis • The diagnosis is more difficult to establish by MRI in some anatomical locations • Specific training should be given concerning those locations that cause difficulty.

MRI and "tenderness guided" transvaginal ultrasonography in the diagnosis of recto-sigmoid endometriosis.

PURPOSE: To compare the diagnostic accuracy of MRI and "tenderness-guided" transvaginal ultrasonography (tg-TVUS) in the identification of recto-sigmoid endometriosis. MATERIALS AND METHODS: Institutional Review Board approval for this study was obtained, and written informed consent was given by all patients. This study is compliant with the STARD (Standards for Reporting of Diagnostic Accuracy) method. Fifty-nine patients (mean age, 33 years; range, 21-44 years) with clinical suspicion of deep pelvic endometriosis were prospectively enrolled. They underwent tg-TVUS and MRI before surgery. The characteristics of the MRI signal were analyzed. Mapping of recto-sigmoid endometriosis was performed and tg-TVUS and MR imaging results were compared with surgical and pathological findings. Sensitivity, specificity, and the positive and negative likelihood ratio (LR+ and LR-) were calculated. Inter-technique concordance was assessed using the Cohen statistic, and receiver operating characteristic (ROC) curves were obtained. Logistic regression analysis was performed. RESULTS: The prevalence of recto-sigmoid endometriosis was 51%. The specificity, sensitivity, and LR+ and LR- were 90%, 73%, 7.089 and 0.297, respectively, for MRI and 86%, 73%, 5.317 and 0.309, respectively, for tg-TVUS. The presence of a high T1 signal spot was an excellent specific finding (100%) but was associated with a low sensitivity (30%). Inter-technique concordance using the Cohen statistic indicated a kappa value of 0.658 (± 0.098 SD). According to the logistic regression equation obtained, the use of both tg-TVUS and MRI allows optimal diagnostic performance. CONCLUSION: MRI and tg-TVUS show similar results in the identification of recto-sigmoid endometriosis. The Cohen kappa value suggests that these methods may have complementary roles in the identification of recto-sigmoid endometriosis, depending on the site affected.

Agreement and reproducibility in identification of endometriosis using magnetic resonance imaging.

BACKGROUND: Magnetic resonance imaging (MRI) is a promising technique in the study of endometriosis, allowing a complete mapping of lesions before surgery. However, the value of MRI in the diagnosis of endometriosis in the bladder, in superficial peritoneal lesions, and in ovarian foci and uterosacral ligaments is still under debate. PURPOSE: To assess inter- and intra-observer agreement in the evaluation of endometriosis in different anatomical locations using MRI. MATERIAL AND METHODS: From June 2006 to February 2008, 83 female patients (mean age 39, range 19-49 years) who had undergone MRI examination for suspected endometriosis were evaluated by two radiologists. MRI at 1.5 Tesla was performed with SE and TSE sequences, T1- and T2-weighted with and without fat suppression. Each examination was completed with gadolinium administration. Each dataset was independently evaluated by the radiologists for the presence or absence of endometriosis. The location (ovaries, uterosacral ligaments (USLs), pouch of Douglas, vagina, rectosigmoid, rectovaginal septum, and bladder) of suspected lesions was recorded. Cohen kappa statistical analysis was performed to calculate agreement between measurements. After 2 months the data were analyzed again by the two observers to assess intra-observer agreement. RESULTS: Of the 83 MRI examinations performed, 12 patients demonstrated no evidence of endometriosis. In the remaining 71 studies, 157 endometriotic lesions ranging in size from 0.4 to 6.2 cm were detected. Of the 157 lesions, 53 (33.75% incidence) were smaller than 1 cm. In the ovaries, the inter-observer agreement was 92.77% and the kappa value was 0.802 (95% CI, 0.695-0.91). In the bladder the inter-observer agreement was 96.39% and the kappa value was 0.553 (95% CI 0.056-1). In the USLs the inter-observer agreement was 90.96% and the kappa value 0.583 (95% CI, 0.381-0.784). In the rectovaginal septum the inter-observer agreement was 94.58% and the kappa value 0.739 (95% CI, 0.572-0.905). In the rectovaginal pouch the inter-observer agreement was 88.55% and the kappa value 0.608 (95% CI, 0.443-0.774). In the vaginal fornix the inter-observer agreement was 94.58% and the kappa value 0.726 (95% CI, 0.552-0.901). In the rectosigmoid the inter-observer agreement was 89.76% and the kappa value 0.589 (95% CI, 0.389-0.768). CONCLUSION: The results of our study indicate that MRI has a high inter- and intra-observer agreement in the identification of endometriosis located in the ovary, rectosigmoid, and rectovaginal septum, whereas the agreement is suboptimal for the identification of endometriosis located in the USLs.

Mature and immature ovarian teratomas: CT, US and MR imaging characteristics.

Ovarian teratomas (OTs) are the most common germ cell neoplasm. They include mature cystic teratomas, monodermal teratomas (neural tumors, struma ovarii, carcinoid tumors) and immature teratomas. Teratomas are the most common benign ovarian neoplasms in women less than 45 years old. OTs are usually characterized by ultrasound (US) and magnetic resonance (MR) whereas they are usually an incidental finding on CT. The purpose of this paper is to review the most common types of teratomas and to describe CT, US and MR imaging features of the various types of mature and immature OTs.