You have accessJournal of UrologyUrodynamics/Incontinence/Female Urology: Urodynamics Testing1 Apr 20132276 FLUID BIOMECHANICS OF MALE UROFLOW USING IMAGE PROCESSING OF HIGH-SPEED VIDEO PHOTOGRAPHY Kristy Weins, S Green, D Grecov, and Lynn Stothers Kristy WeinsKristy Weins vancouver, Canada More articles by this author , S GreenS Green vancouver, Canada More articles by this author , D GrecovD Grecov vancouver, Canada More articles by this author , and Lynn StothersLynn Stothers vancouver, Canada More articles by this author View All Author Informationhttps://doi.org/10.1016/j.juro.2013.02.2205AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookTwitterLinked InEmail INTRODUCTION AND OBJECTIVES In men, uroflow and pressure flow studies quantify flow rate and bladder pressure, but do not describe other fluid flow characteristics of the urinary stream. The objective of this study was to report fluid flow characteristics, such as surface roughness and stream length, of the stream not visible to the naked eye or observed in standard urodynamic measurements using image processing and mathematical analysis of high-speed video photography. METHODS 10 pathologic and 10 control subjects participated. Pathologic subjects were men aged 35 to 80 with obstructive LUTS, free of UTI, and scheduled for urodynamics at a tertiary care teaching centre at the University of British Columbia. Controls were asymptomatic male volunteers with no prior surgery or condition of the LUT based on history and IPSS questionnaire. A Phantom V611 high-speed camera imaged the urinary stream in profile during repeated uroflow, capturing greyscale images at 800x600 resolution, 24 frames per second, and 90 μs exposure. Degrees of obstruction were quantified with multichannel pressure flow plotted on Abrams Griffiths nomograms. RESULTS The urinary stream was isolated using image subtraction and thresholding techniques in MATLAB. The length and surface roughness of the inertia stream were determined. Surface roughness was measured as the sum of squared difference between the stream edge points and a highly smoothed curve fit to these points. For all subjects, the urinary stream was divisible into two distinct segments: the inertia stream and a region in which surface tension dominates inertia, breaking the stream into droplets (Figure 1). In pathologic subjects, the time for the inertia stream to reach steady length ranged from 0.5 to 5 s and increased quadratically with increased bladder pressure (r2=0.7). The length of the inertia stream ranged from 34±4 to 120±4 mm in pathologic subjects. No relationship between surface roughness and bladder pressure was found in pathologic subjects. CONCLUSIONS It is feasible to clearly observe the urinary stream and analyze its characteristics using image processing techniques. In pathologic subjects, the time to steady inertia stream increased quadratically with increasing bladder pressure (r2=0.7). © 2013 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 189Issue 4SApril 2013Page: e933-e934 Advertisement Copyright & Permissions© 2013 by American Urological Association Education and Research, Inc.MetricsAuthor Information Kristy Weins vancouver, Canada More articles by this author S Green vancouver, Canada More articles by this author D Grecov vancouver, Canada More articles by this author Lynn Stothers vancouver, Canada More articles by this author Expand All Advertisement Advertisement PDF downloadLoading ...