Doppler Evaluation of Erectile Dysfunction - Part 1

D Golijanin; E Singer; R Davis; S Bhatt; A Seftel; V Dogra

Disclosures

Int J Impot Res. 2007;19(1):37-42. 

In This Article

Phases of erection

The erection process may be divided into four phases. First, the flaccid phase during which corporeal volume is small, approximately one-fifth of maximal volume, and corporeal pressure is around 20 mm Hg. In the filling and tumescence phase, the corporeal smooth muscle is relaxed owing to reduction in the sympathetic tonus of the arteries allowing brief arterial inflow. The corpora cavernosa are engorged with blood. This results in increase of pressure inside corpora cavernosa, causing pressure at the level of the relaxed veins against the tunica albuginea and preventing outflow. The hemodynamic resistance of the veins increases significantly. This leads to fourth phase of rigidity, where intracavernosal volume grows almost five times baseline and intracorporeal pressure is close to systolic systemic arterial pressure. Final rigidity is obtained by contraction of the perineal muscles that generate high-pressure peaks giving the rigidity required for full erection. Doppler ultrasonography accurately divides phases of erection with characteristically different spectral waveforms as seen in Figure 3.

Figure 3.

Phases of erection. (a) Flaccid phase. Spectral Doppler waveform demonstrates high resistance waveform. Velocities are in the range of 5–15 cm/s. (b) Filling phase. Spectral Doppler waveform demonstrates increased systolic velocity and increased diastolic flow. (c) Tumescent phase. The systolic velocities stabilize, diastolic flow decreases or becomes reversed. (d) Rigid phase. Spectral Doppler waveform demonstrates very high resistance waveform with no diastolic flow and minimal systolic flow. The peak systolic velocities decrease.


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