World J Urol (2009) 27:747–753 DOI 10.1007/s00345-009-0392-2 O R I G I N A L A R T I C L E Manual versus automatic bladder wall thickness measurements: a method comparison study Matthias Oelke · Charalampos Mamoulakis · Dirk T. Ubbink · Jean J. de la Rosette · Hessel Wijkstra Received: 18 November 2008 / Accepted: 4 February 2009 / Published online: 24 February 2009 © The Author(s) 2009. This article is published with open access at Springerlink.com Abstract Purpose To compare repeatability and agreement of conventional ultrasound bladder wall thickness (BWT) measurements with automatically obtained BWT measure- ments by the BVM 6500 device. Methods Adult patients with lower urinary tract symp- toms, urinary incontinence, or postvoid residual urine were urodynamically assessed. During two subsequent cystome- try sessions the infusion pump was temporarily stopped at 150 and 250 ml bladder Wlling to measure BWT with con- ventional ultrasound and the BVM 6500 device. For each method and each bladder Wlling, 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 (signiWcant only during the M. Oelke and C. Mamoulakis have equally contributed to the manuscript. M. Oelke (&) Department of Urology and Urologic Oncology, Hannover Medical School, Carl-Neuberg-Str. 1, 30625 Hannover, Germany e-mail: oelke.matthias@mh-hannover.de M. Oelke · C. Mamoulakis · J. J. de la Rosette · H. Wijkstra Department of Urology, Academic Medical Center, Amsterdam, The Netherlands D. T. Ubbink Department of Quality Assurance and Process Innovation and Surgery, Academic Medical Center, Amsterdam, The Netherlands second measurement at 150 ml bladder Wlling). Mean diVerence in BWT values between the measurements of one technique was ¡0.1 to +0.01 mm. Measurement varia- tion between replicate measurements was smaller for con- ventional ultrasound and the smallest for 250 ml bladder Wlling. Mean diVerence between the two techniques was 0.11–0.23 mm and did not diVer signiWcantly. 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. Keywords Bladder wall thickness · Ultrasound · BVM 6500 · Repeatability · Accuracy Abbreviations BWT Bladder wall thickness BS Bladder scan, automatic BWT measurement with the BVM 6500 device, Verathon® BS150A BS during Wrst urodynamic investigation at 150 ml bladder Wlling BS250A BS during Wrst urodynamic investigation at 250 ml bladder Wlling BS150B BS during second urodynamic investigation at 150 ml bladder Wlling BS250B BS during second urodynamic investigation at 250 ml bladder Wlling US Ultrasound, BWT measurement with conventional ultrasound machine US150A US during Wrst urodynamic investigation at 150 ml bladder Wlling US250A US during Wrst urodynamic investigation at 250 ml bladder Wlling 123