Maximum-distention retrograde urethrocystography in healthy male dogs: occurrence and radiographic appearance of urethroprostatic reflux.

: Urethroprostatic reflux was found during retrograde urethrocystography in 21 of 24 mature healthy Beagles. Minimal parenchymal-positive contrast " blushes " near the urethra were identified, but no massive accumulations of contrast medium within the prostate were found. A particulate contrast medium, sterilized barium sulfate, was used in 12 of the dogs. After retrograde urethrocystography, the barium particles were found in the secretory (acinar) portion of the prostatic parenchyma, confirming that urethroprostatic reflux extended beyond the prostatic duct system that directly empties into the urethral lumen.