title: Manual versus automatic bladder wall thickness measurements: a method comparison study.
abstract: OBJECTIVE
  To compare repeatability and agreement of conventional ultrasound bladder wall thickness (BWT) measurements with automatically obtained BWT measurements by the BVM 6500 device.
  
  
  METHODS
  Adult patients with lower urinary tract symptoms, urinary incontinence, or postvoid residual urine were urodynamically assessed. During two subsequent cystometry sessions the infusion pump was temporarily stopped at 150 and 250 ml bladder filling to measure BWT with conventional ultrasound and the BVM 6500 device. For each method and each bladder filling, repeatability and variation was assessed by the method of Bland and Altman.
  
  
  RESULTS
  Fifty unselected patients (30 men, 20 women) aged 21–86 years (median 62.5 years) were prospectively evaluated. Invalid BWT measurements were encountered in 2.1–14% of patients when using the BVM 6500 versus 0% with conventional ultrasound (significant only during the second measurement at 150 ml bladder filling). Mean difference in BWT values between the measurements of one technique was −0.1 to +0.01 mm. Measurement variation between replicate measurements was smaller for conventional ultrasound and the smallest for 250 ml bladder filling. Mean difference between the two techniques was 0.11–0.23 mm and did not differ significantly. The BVM 6500 device was not able to correctly measure BWTs above 4 mm.
  
  
  CONCLUSIONS
  Both BWT measurements are repeatable and agree with each other. However, conventional ultrasound measurements have a smaller measurement variance, can measure BWT in all patients, and BWTs above 4 mm.
authors.affiliation: Department of Urology and Urologic Oncology, Hannover Medical School, Carl-Neuberg-Str. 1, 30625 Hannover, Germany. oelke.matthias@mh-hannover.de
authors.forename: Matthias
authors.initials: M
authors.lastname: Oelke
authors.forename: Charalampos
authors.initials: C
authors.lastname: Mamoulakis
authors.forename: Dirk T
authors.initials: DT
authors.lastname: Ubbink
authors.forename: Jean J
authors.initials: JJ
authors.lastname: de la Rosette
authors.forename: Hessel
authors.initials: H
authors.lastname: Wijkstra
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D015203:Reproducibility of Results; D014463:Ultrasonography / Q000295:instrumentation / Q000379:methods* / Q000592:standards*; D001743:Urinary Bladder / Q000000981:diagnostic imaging*; D014549:Urinary Incontinence / Q000000981:diagnostic imaging*; D014556:Urine; D014563:Urodynamics; D055815:Young Adult