Penis

Erectile Dysfunction

Doppler for vascular causes of ED. Injection of vasoactive drugs like papaverin and prostaglandin E into corpora cavernosa → increase in arterial flow into bilateral cavernosal arteries > 35 cm/s is nl. If arterial inflow is nl and RI stays below 0.8 (no stenosis) but unable to maintain erection --> venous outflow mechanism leak should be suspected

Priapism

AVF (high flow priapism) or thrombosis of the dorsal penile vein (venous outflow mechanism obstruction, low-flow priapism)

Peyronie’s disease

Fibrosis of the tunica albuginea of the corpora cavernosa --> penis bend toward the plaque during erection --> pain. Localized area of thickening of the tunica albuginea sometimes w/ calcs, along the dorsum of the penis base