Comparison of magnetic resonance imaging and transvaginal ultrasonography in diagnosing bladder endometriosis

STUDY OBJECTIVE: To take recent progress in magnetic resonance imaging (MRI) into account to determine its accuracy compared with that of transvaginal ultrasonography (TVUS) in diagnosing bladder endometriosis. DESIGN: Retrospective analysis (Canadian Task Force classification II-2). SETTING: University-affiliated hospital. PATIENTS: Twelve women with histologically proved bladder endometriosis. INTERVENTION: Magnetic resonance imaging with body and endocavitary coils and TVUS. MEASUREMENTS AND MAIN RESULTS: Although TVUS was normal in four patients, MRI enabled endometriotic lesions to be detected in all patients. Magnetic resonance imaging with endocavitary coil established the existence of deep infiltration in three patients when muscularis involvement was not visible with the body coil. In seven women MRI determined how far deep posterior endometriotic lesions extended, whereas with TVUS this was impossible to see. Conclusion. MRI had advantages over TVUS in diagnosing small lesions of associated posterior deep endometriotic lesions. The endocavitary coil gave better results than the phased-array coil for diagnosing deep infiltration. These results are important in that they help guide surgical management.