Knowledge of the precise location of endometriosis is essential for a successful surgical treatment. MRI Susceptibility-Weighted Imaging (SWI-MRI) yields high sensitivity for blood by-products detection. Since endometriosis lesions are haemorrhagic, and therefore rich in blood by-products such as hemosiderin, SWI-MRI could be useful in the pre-operative assessment of endometriosis, especially in superficial peritoneal lesion detection. The purpose of our study is to evaluate the performance of SWI-MRI for the preoperative work-up of endometriosis