Rectal endometriosis (RE) induces lesions 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 investigation is to evaluate the safety of the HIFU treatment of rectal endometriosis with Focal One® HIFU device.

Inclusion Criteria:

• Patients aged at least 25 years-old
• Rectal endometriosis in preoperative imaging, without other digestive locations (colon, ileum and small intentine)
• Symptomatic patient refusing hormonal treatment and/or surgery.
• Endometriosic nodule visible on echography with contrast and confirmed in Gadolinium MRI and difusion sequence (according to standardized protocol)
• Nodule with intrarectal protrusion of less than 50% (allowing the positioning of the probe in front of the rectal nodule)
• Distance from the upper pole to the anal margin ≤ 15 cm (measurement by MRI with intra-rectal contrast)
• No curent pregnancy (negative BHCG <72h before the HIFU procedure) and no pregnancy project within 6 months after the HIFU procedure (post-treatment MRI delay)
• Patient agreeing not to change her hormone treatment for the duration of the study.
• Patient accepting the study constraints
• Health insurance affiliated patient or beneficiary of an equivalent coverage

Exclusion Criteria:

• Virgin patient
• Ongoing uro-genital infection
• Anorectal anatomy incompatible with HIFU therapy
• History of segmental rectal resection with mechanical anastomosis, shaving or discoid resection
• Patient with an implant within 1cm of the treatment area (stent, catheter, ESSURE® contraceptive implants).
• Inflammatory colon disease (ulcerative colitis, Crohn's disease and others)
• Latex allergy
• Patient with contraindications to MRI
• Patient with contraindications to Gadolinium injection
• Patient previously treated with HIFU for a rectal endometriotic lesion
• Patient not speaking nor reading French
• Patient deprived of liberty following a legal or administrative decision
• Patient under guardianship or tutelage measure