Evaluation of a 3-dimensional ultrasound device for noninvasive measurement of urinary bladder volume in dogs.

BACKGROUND

The BladderScan Prime Plus (BPP; Verathon, Bothell, Washington) is an application-specific, three-dimensional ultrasound device used for human, point-of-care volumetry of the urinary bladder.

OBJECTIVE

To estimate the BPP's accuracy, repeatability, and optimized settings for assessing urinary bladder volumes in dogs, a variable utilized in assessing micturition disorders.

ANIMALS: Twenty-four, client-owned, healthy, male dogs presenting for routine examination.

METHODS

Prospective examinations were conducted by an experienced ultrasonographer and a novice, selecting the BPP's "man" or "child" setting, and were compared to urine volume obtained by catheterization.

RESULTS

Mean urine volume significantly varied by operator (P = .05), device setting (P < .001), and weight (P = .01); the "man" setting produced mean volumes nearer to catheterized volumes. The mean difference between BPP's "man" setting and catheterized volume was 0.88 mL, with maximal positive and negative disagreement of +23.2 mL to -55.3 mL (SD 19.0). Percent disagreement between BPP and catheterized volumes demonstrated a mean of -4.5%, with maximal positive and negative disagreement of +58.1% to -74.1% (SD 34.9). The experienced operator recorded volumes significantly (P = .05) higher than the novice, with difference in means of 3.2 mL. In dogs weighing >5.5 kg (n = 18/24), mean difference between BPP's "man" setting and catheterized measurements, regardless of operator, was not significant.

CONCLUSIONS

Although small magnitude interuser variability is present in BPP examinations, the device provides accurate, though imprecise quantification of bladder volume in canids weighing >5.5 kg.