Portable Ultrasonography and Bladder Volume Accuracy—A Comparative Study Using Three-Dimensional Ultrasonography
Received 25 November 2007; accepted 16 February 2008. published online 08 April 2008.
Objectives
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.
aDepartment of Urology, St. George's Hospital Medical School, London, United Kingdom
bDepartment of Radiology, St. George's Hospital Medical School, London, United Kingdom
cDepartment of Clinical Physics and Ultrasound, St. George's Hospital Medical School, London, United Kingdom
Reprint requests: Khurshid Ghani, B.Sc.(Hons.), M.B.Ch.B., M.R.C.S.(Ed.), Department of Urology, St. George's Hospital, Blackshaw Road, London SW17 0JT United Kingdom.
ABSTRACT