title: Portable ultrasonography and bladder volume accuracy--a comparative study using three-dimensional ultrasonography.
abstract: OBJECTIVE
  To compare the ultrasound bladder volume accuracy and level of agreement between two portable bladder scanners (Bladderscan and Bardscan) and a three-dimensional ultrasound (3D-US) system.
  
  
  METHODS
  A total of 50 healthy volunteers were scanned using the Bladderscan BVI 3000, Bardscan, and 3D-US system (HDI 4000), in random sequence. The BVI3000 is a dedicated bladder volume calculator, and the Bardscan combines real-time ultrasonography with bladder volume calculation. The ultrasound bladder volumes were compared with the voided volume measurements. The volunteers underwent repeat scanning after voiding, and those with a measurable residual volume were excluded from the final analysis.
  
  
  RESULTS
  A residual volume was detected in 16 subjects (32%). In the remaining 34 subjects, the mean voided volume +/- standard deviation was 252.9 +/- 167.4 mL (range 33 to 709). A significant correlation (P <0.001) was found between the voided and ultrasound volumes with all three methods (Bardscan, r = 0.97; Bladderscan, r = 0.98; and 3D-US system, r = 0.99). No significant differences were found between the voided volumes and the Bladderscan or 3D-US volumes; however, the Bardscan significantly underestimated the voided volume by a mean of 21.4 mL (t = 2.84, P = 0.0076). The Bland-Altman 95% limit of agreement between the voided and calculated volumes was -64.5 to 107.2 mL, -73.7 to 88.4 mL, and -28.9 to 40.0 mL for the Bardscan, Bladderscan, and 3D-US systems, respectively.
  
  
  CONCLUSIONS
  The results of our study have shown that although the Bardscan has the advantages of real-time scanning with portability and instantaneous volume calculation, it is not as accurate as the Bladderscan. The accuracy and level of clinical agreement was greatest when using the 3D-US system to calculate the bladder volume.
authors.affiliation: Department of Urology, St. George's Hospital Medical School, London, United Kingdom. krghani@gmail.com
authors.forename: Khurshid R
authors.initials: KR
authors.lastname: Ghani
authors.forename: James
authors.initials: J
authors.lastname: Pilcher
authors.forename: David
authors.initials: D
authors.lastname: Rowland
authors.forename: Uday
authors.initials: U
authors.lastname: Patel
authors.forename: Daruish
authors.initials: D
authors.lastname: Nassiri
authors.forename: Ken
authors.initials: K
authors.lastname: Anson
mesh_terms: D000328:Adult; D005260:Female; D006801:Humans; D021621:Imaging, Three-Dimensional; D008297:Male; D008875:Middle Aged; D009929:Organ Size; D012016:Reference Values; D014463:Ultrasonography / Q000295:instrumentation*; D001743:Urinary Bladder / Q000000981:diagnostic imaging* / Q000502:physiology; D014563:Urodynamics