Figure 12b. Vesicourethral fistulas. (a) VCUG image shows a false urethral passage (arrow), which extends from the prostatic urethra to the base of the bladder and was created intentionally. (b) VCUG image obtained later shows that the fistula has become the dominant channel, whereas the prostatic urethra has closed. (c) VCUG image of another patient shows a spontaneously formed fistula, which was secondary to a urethral diverticulum (arrow).