Analysis of human ejaculation using color Doppler ultrasonography: a comparison between antegrade and retrograde ejaculation.

OBJECTIVES To observe the phenomenon of human ejaculation dynamically using color Doppler ultrasonography. METHODS Human ejaculation was observed using transrectal color Doppler ultrasonography in a healthy man and a patient with retrograde ejaculation. Ejaculation was induced manually with audiovisual sexual stimulation. The ejaculatory phenomenon was analyzed and compared with that of retrograde ejaculation. RESULTS In the healthy man, the prostatic urethra flattened slightly and the bladder neck contracted just before expulsion. The ejaculatory stream spurted from the seminal vesicles to the bulbous urethra through the ejaculatory duct. In the patient with retrograde ejaculation, the ejaculatory stream from the seminal vesicles and inframontanal and distal prostatic urethras distended into a globular-shaped sac filled with semen. No seminal flow toward the bulbous urethra occurred. The semen remaining in the prostatic urethra began flowing slowly into the bladder. CONCLUSIONS Differences between antegrade and retrograde ejaculation can be clearly detected by color Doppler ultrasonography, providing a noninvasive method to diagnose ejaculatory disorders.