Inclusion Criteria:  Over 50 years of age, BPH greater than 30 cc confirmed by endorectal ultrasound IPSS score > 7, Qol-IPSS > 2, IIEF-5 score > 11 Qmax < 15 ml/s or urinary retention (in indwelling catheter, self-catheterization, or with an RPM > 300 cc). In failure or intolerance of drug treatment(s) for BPH negative cytobacteriological examination of the urine  Exclusion Criteria:  Prostate volume > 80 ml Presence of a median lobe Men allergic to latex Contraindication to the insertion of a transrectal HIFU probe: rectal fistula, anal or rectal fibrosis, or other abnormalities History of prostate surgery History of prostate radiation therapy History of bladder cancer Current anti-coagulant treatment with a stopping window that cannot exceed 48 hours at the time of the HIFU procedure Presence of a urinary tract fistula History of inflammatory bowel disease Ongoing urogenital infection Neurological bladder pathology History of urethral stenosis Confirmed or suspected prostate cancer Contraindication to surgery (including anesthesia) Contraindication to pelvic MRI Presence of metallic implants or stents in the urethra Presence of prostatic calcification whose location interferes with HIFU treatment Patients with renal failure with a GFR <35ml/min