Best Practices: Ultrasound Versus MRI in the Assessment of Pelvic Endometriosis

Endometriosis is a common yet morbid disease. Imaging plays an important role in diagnosis and treatment planning. Both ultrasound (US) and MRI are used to detect disease. We performed a literature review to assess whether one is superior. A total of 33 studies from the 4482 identified in the initial search were found to assess the efficacy of US and/or MRI in detecting pelvic endometriosis. Most studies were performed at centers with extensive experience with endometriosis, using dedicated US and MRI protocols. A wide range of sensitivities and specificities were reported, but overall weighted means of diagnostic statistics for US and MRI were similar. The choice of dedicated US versus dedicated MRI in the evaluation of endometriosis should therefore be based on the expertise in the region. The data also showed US had better accuracy than MRI for identifying the depth of wall invasion in bowel-wall disease, whereas MRI better depicted pelvic-wall and extraperitoneal disease than US. Routine US and MRI protocols performed worse than dedicated US and MRI protocols, which may account for delays in diagnoses. Clinical and research efforts directed at improving the sensitivity of routine imaging for diagnosing deep endometriosis could improve patient access to appropriate care.