Inclusion Criteria:  Patient aged between 12 and 20 years old. After menarche. Requiring pelvic MRI for exploration of dysmenorrhea (after or not ultrasound), in the case of patients with suspected endometriosis, or for any other reason (cyst, tumor, non-obstructive urogenital malformations), in the case of patients without symptoms clinic associated with endometriosis. Patient affiliated or beneficiary of a social security scheme. Patient and her legal representative, if applicable, having been informed and not opposing this research.  Exclusion Criteria:  Patient whose pelvic MRI is performed as part of an exploration of obstructive uterine malformations. Patient claustrophobic, making it impossible to perform an MRI. Contraindication to MRI: pacemaker, ferromagnetic object incompatible with MRI. Pregnant, breastfeeding or parturient woman. Protected patient: Major under guardianship, curatorship or other legal protection, deprived of liberty by judicial or administrative decision; Hospitalized without consent.