Pelvic endometriosis: US and MRI features

Endometriosis represents a common and important clinical problem of women of childbearing age. It is a disabling disorder manifesting with pain and infertility. The exact pathogenesis of the disease remains unclear, despite the different theories that have been formulated. The literature on endometriosis is extensive, but often in regard to classic endometrioma. It is surprising that, to the best of our knowledge, the many radiologic features of extraovarian endometriosis have not been well documented thus far. Although ultrasound (US) remains the imaging modality of choice in the radiologic evaluation of female patients with pelvic pain, the role of magnetic resonance imaging (MRI) in the evaluation of abdominal pain is expanding. In the young patient, MRI may be performed if a gynecologic disorder is not suspected at first, especially if US findings are equivocal or the abnormality extends beyond the field of view of the sonographic probe. Moreover, MRI is useful whenever further characterization of pelvic disorder is required. In fact, many causes of pelvic disorders and of endometriosis in particular demonstrate characteristic MRI findings. For these reasons, in this work we describe the protean US and MRI appearances of endometrial foci as encountered in daily experience.