title: Posterior urethral valves in male infants and newborns: detection with US of the urethra before and during voiding.
abstract: OBJECTIVE
  To document the appearance and width of the posterior urethra with transperineal ultrasound (US) before and during voiding in male infants and newborns with posterior urethral valves.
  
  
  METHODS
  Thirty-three patients with bilateral hydronephrosis underwent prospective transabdominal and transperineal US.
  
  
  RESULTS
  Fifteen patients had proved posterior urethral valves (obstructed group); 18 patients had no obstruction (unobstructed group). In the obstructed group, the median posterior urethral width was 4.5 mm before and 10.0 mm during voiding. In the unobstructed group, the median posterior urethral width was 1.0 mm (P = .046) before and 4.0 mm (P < .001) during voiding. Bladder wall thickness was 3.0-7.6 mm (obstructed group) and 2.0-5.0 mm (unobstructed group; P < .001). With a posterior urethral diameter of at least 6 mm during voiding as a criterion for transperineal US diagnosis of obstruction, sensitivity was 100%; specificity, 89%; and positive predictive value, 88%.
  
  
  CONCLUSIONS
  Transperineal voiding US is noninvasive and useful in diagnosing posterior urethral valves.
authors.affiliation: Department of Radiology, Great Ormond Street Hospital for Children, London, England.
authors.forename: C D
authors.initials: CD
authors.lastname: Good
authors.forename: S J
authors.initials: SJ
authors.lastname: Vinnicombe
authors.forename: I L
authors.initials: IL
authors.lastname: Minty
authors.forename: A D
authors.initials: AD
authors.lastname: King
authors.forename: S J
authors.initials: SJ
authors.lastname: Mather
authors.forename: C
authors.initials: C
authors.lastname: Dicks-Mireaux
mesh_terms: D016022:Case-Control Studies; D000013:Congenital Abnormalities / Q000000981:diagnostic imaging; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D011237:Predictive Value of Tests; D011446:Prospective Studies; D012680:Sensitivity and Specificity; D014463:Ultrasonography; D014521:Urethra / Q000002:abnormalities* / Q000000981:diagnostic imaging; D014524:Urethral Obstruction / Q000000981:diagnostic imaging* / Q000209:etiology; D014554:Urination