ASSESSMENT OF URINARY-BLADDER VOLUME IN DOGS BY USE OF LINEAR ULTRASONOGRAPHIC MEASUREMENTS

Objective-To evaluate accuracy of formulas derived from linear ultraso nographic measurements and used in human beings to assess urinary blad der volume as a method of estimating bladder volume in dogs and to tes t reproducibility of ultrasonographic measurements of linear bladder d imensions. Animals-64 live dogs (for bladder volume determination) and 31 fresh canine cadavers (for ultrasonographic assessment of reproduc ibility of measurements). Procedure-Maximal length, longitudinal and t ransverse depth (DL and DT), and width were measured from the maximal longitudinal and transverse images. Bladder volume was estimated, usin g 6 formulas, and calculated volumes were compared statistically with the actual volume obtained by catheterization, using paired nonparamet ric tests. Reproducibility of bladder dimensions was investigated by m easuring length, DL, DT, and width 3 times from each image of section. Measurements of depth (DL and DT) also were compared. Results-Calcula tions of bladder volume from linear dimensions, using a formula descri bed for use in human beings, gave a satisfactory indication of actual bladder volume; the median difference between actual and calculated vo lumes was only 5 ml. Bladder volume estimations were less accurate whe n large-volume bladders were measured. Matching between repealed measu rements was significant (P < 0.005 for longitudinal bladder length and P < 0.0001 for bladder depth and width). Measurements of DL and DT we re significantly (P < 0.01) different, with DL greater than DT. Conclu sions-Ultrasonographic assessment of bladder volume in dogs by applica tion of the formula is sufficiently accurate for most clinical purpose s. Clinical Relevance-Ultrasonography would be a useful method of esti mating bladder volume in dogs with severe obstruction or dysfunctional voiding of urine.