Treatment by HIFU With Focal One® of Posterior Deep Infiltrating Endometriosis Lesions With Intestinal Involvement.

Deep invasive endometriosis (DIE) includes lesions of the rectosigmoid. Theses lesions are associated with painful symptoms that can alter quality of life. High Intensity Focused Ultrasound (HIFU) is a non-invasive ablative procedure using a high-intensity ultrasound probe to induce tissue devitalization using acoustic cavitation and thermal ablation. Focal One® is a transrectal HIFU device, which is validated to treat prostatic cancer.

The primary objective of this clinical trial is to evaluate the ability of the Focal One® HIFU device to detect and target posterior DIE lesions with intestinal involvement. The secondary objectives are to perform a HIFU lesion, to evaluate morphological modifications of the nodule in post-therapeutic imaging scans, to assess evolution of gynecological symptoms, intestinal symptoms, and patients' quality of life after treatment by HIFU and to collect safety data.

20 Subjects with deep invasive endometriosis (DIE) will receive the HIFU treatment with Focal One® device.

Subjects harboring an isolated recto-sigmoid DIE lesion with a persistence of symptoms despite hormonal treatment will be installed on the Focal One® device to:

* Evaluate its ability to locate and assess the volume of the endometriosic lesion
* Treat the targeted lesion by HIFU energy application. Real-time guided ultrasonography will be used to determine the location of the endometriosic nodule. Succession of HIFU exposure will be then used to treat maximum lesion volume, excluding a security margin of 3 mm with the digestive mucosae to prevent risk of fistulae.

Patients will fill-out questionnaires on gynecological and intestinal symptoms and on quality of life before treatment and at 1 and 6 months after HIFU procedure. Imaging follow-up scans will be organized at 1 and 6 months and by a pelvic MRI scan at 3/6 months.

Eligibility Criteria:
Inclusion Criteria:

* Age \> 25 years
* Isolated recto-sigmoid DIE lesion, with no other endometriosis location on imaging examination (intestinal, urinary or ovarian), the persistence of symptoms despite hormonal treatment and therefore consideration for surgical management.
* Localization of endometriosic lesion described by US, confirmed by MRI
* Negative urinary pregnancy test and No intention to get pregnant during the following 6 months
* Affiliated to the French Social Security System

Exclusion Criteria:

* Hormonal treatment of endometriosis by Luteinizing Hormone Releasing Hormone agonist (LHRH analogs) of less than 3 months
* Breastfeeding female
* Uro-genital infection in progress (the infection has to be treated before HIFU treatment)
* Anatomical abnormality of the rectum
* Anterior surgery at the level of the anus or rectum
* Presence of an implant (stent, catheter, contraceptive implant) located less than 1 cm from the treatment area.
* History of intestinal inflammatory pathology
* Allergy to latex
* Female with a medical contraindication on MRI
* Female with a medical contraindication to Sonovue® injection
* Female not able to understand the objectives of the study
* Legal person protected by law