title: Ultrasound assessment of detrusor thickness in men-can it predict bladder outlet obstruction and replace pressure flow study?
abstract: OBJECTIVE
  We estimated the diagnostic accuracy of ultrasound detrusor thickness measurement for BOO and investigated whether this method can replace PFS for the diagnosis of BOO in some patients with lower urinary tract symptoms.
  
  
  METHODS
  Detrusor thickness was measured by linear ultrasound (7.5 MHz) at a filling volume of greater than 50% of cystometric capacity in 102 men undergoing PFS for LUTS. All patients with prior treatment for bladder outlet obstruction and those with underlying neurological disorders were excluded from analysis. Detrusor thickness was correlated with PFS data. Obstruction was defined according to the Abrams-Griffiths nomogram.
  
  
  RESULTS
  Detrusor thickness was significantly higher (p <0.0001) in obstructed (61 cases, median detrusor thickness 2.7 mm, IQR 2.4 to 3.3) compared to unobstructed (18 cases, median detrusor thickness 1.7 mm, IQR 1.5 to 2) as well as equivocal (23 cases, median detrusor thickness 1.8 mm, IQR 1.5 to 2.2) cases. A weak to medium Spearman correlation was found between detrusor thickness and PFS parameters. For a diagnosis of BOO, detrusor thickness of 2.9 mm or greater had a positive predictive value of 100%, a negative predictive value of 54%, specificity of 100% and sensitivity of 43%. ROC analysis revealed that detrusor thickness had a high predictive value for BOO with an AUC of 0.88 (95% CI 0.81-0.94).
  
  
  CONCLUSIONS
  In men with LUTS without prior treatment and/or neurological disorders, ultrasonographically assessed detrusor thickness 2.9 mm or greater has a high predictive value for BOO and can replace PFS for the diagnosis of BOO. However, this cutoff value needs to be validated in a larger study population.
authors.affiliation: Department of Urology, University of Bern, Bern, Switzerland. tkessler@gmx.ch
authors.forename: Thomas M
authors.initials: TM
authors.lastname: Kessler
authors.forename: Rolf
authors.initials: R
authors.lastname: Gerber
authors.forename: Fiona C
authors.initials: FC
authors.lastname: Burkhard
authors.forename: Urs E
authors.initials: UE
authors.lastname: Studer
authors.forename: Hansjörg
authors.initials: H
authors.lastname: Danuser
mesh_terms: D000368:Aged; D006801:Humans; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D011312:Pressure; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014463:Ultrasonography; D001743:Urinary Bladder / Q000000981:diagnostic imaging* / Q000473:pathology*; D001748:Urinary Bladder Neck Obstruction / Q000000981:diagnostic imaging* / Q000503:physiopathology*; D014563:Urodynamics