title: Analysis of energy loss mediated by an alpha-1 blocker in patients with benign prostatic hyperplasia using a virtual urethra processed from an endoscopic video image.
abstract: OBJECTIVE
  To examine the efficacy of an alpha-1 blocker and its correlation to structural alteration of the prostatic urethra and the loss of energy in the urine flow using a virtual urethra processed from an endoscopic video image.
  
  
  METHODS
  Video images of the prostatic urethra were recorded during cystourethroscopy in 11 patients with benign prostatic hyperplasia (BPH) before and after treatment with an alpha-1 blocker, naftopidil. The three-dimensional (3D) structure of the prostatic urethra was reproduced from video files. Fluid dynamic analysis and hydraulic energy calculations were performed using the "virtual" 3D urethral images.
  
  
  RESULTS
  In 9 of 11 patients studied, an 11% improvement in the loss of energy (range, 1%-82%) was seen. Alpha-1 blocker treatment mediated the disappearance or decrease of the bulky vortex formation in seven patients, which led to an improved urinary stream. A positive correlation was found between improved energy loss and residual urine volume (P=0.0312).
  
  
  CONCLUSIONS
  Alpha-1 blocker therapy led to a decreased energy loss in the urine flow in the prostatic urethra in relation to the improvement of clinical symptoms. The cystourethroscopy could be a tool to assess the urethral resistance in patients with BPH using image processing methodology.
authors.affiliation: Department of Urology, Graduate School of Medicine, Chiba University, Chiba, Japan.
authors.forename: Tomokazu
authors.initials: T
authors.lastname: Sazuka
authors.forename: Yoichi
authors.initials: Y
authors.lastname: Kambara
authors.forename: Takuro
authors.initials: T
authors.lastname: Ishii
authors.forename: Kazuyoshi
authors.initials: K
authors.lastname: Nakamura
authors.forename: Shinichi
authors.initials: S
authors.lastname: Sakamoto
authors.forename: Yukio
authors.initials: Y
authors.lastname: Naya
authors.forename: Tomonori
authors.initials: T
authors.lastname: Yamanishi
authors.forename: Tomohiko
authors.initials: T
authors.lastname: Ichikawa
authors.forename: Tatsuo
authors.initials: T
authors.lastname: Igarashi
mesh_terms: D000317:Adrenergic alpha-Antagonists / Q000008:administration & dosage / Q000494:pharmacology / Q000627:therapeutic use*; D004724:Endoscopy; D006801:Humans; D008297:Male; D009281:Naphthalenes / Q000008:administration & dosage / Q000494:pharmacology / Q000627:therapeutic use; D010879:Piperazines / Q000008:administration & dosage / Q000494:pharmacology / Q000627:therapeutic use; D011470:Prostatic Hyperplasia / Q000188:drug therapy* / Q000503:physiopathology; D014521:Urethra / Q000187:drug effects / Q000503:physiopathology; D014554:Urination / Q000187:drug effects* / Q000502:physiology*; D014741:Video Recording
chemical_list: D000317:Adrenergic alpha-Antagonists; D009281:Naphthalenes; D010879:Piperazines; C064357:naftopidil