Objective: To compare the hemodynamic indexes of penile cavernosal arteries in different phases of penile erection and determine the optimal time for color Doppler ultrasonography of the penis.
Methods: Forty healthy adult male volunteers with normal erectile function received intracavernous injection of 10 μg Alprostadil together with visual and auditory stimuli. Within the next 30 minutes, we monitored dynamically the blood flow in the bilateral penile cavernosal arteries, and recorded and compared the peak systolic velocity (PSV), end diastolic velocity (EDV) and resistance index (RI) in the phases of latency, tumescence, full erection and rigid erection.
Results: Fourteen of the subjects experienced latency, tumescence and full erection only, but failed to achieve rigid erection. PSV and RI were significantly higher while EDV remarkably lower in the tumescence and full erection phases than in the latency phase (all P < 0.01). Statistically significant differences were observed between the tumescence and full erection phases in EDV and RI (both P < 0.01) but not in PSV (P > 0.05). Among the 26 males that achieved rigid erection, PSV, EDV and RI showed significant differences between the full and rigid erection phases (all P < 0.01), but not between the left and right cavernosal arteries in the same phase (P > 0.05).
Conclusions: The blood flow in the penile cavernosal arteries changes dynamically in the process of penile erection, and the hemodynamic indexes obtained in the full erection phase can better reflect the function of penile cavernous vessels.
Keywords: color Doppler ultrasonography; erection phase; hemodynamics; penis.