Penile Duplex with Vasodilator Challenge Test

Penile Doppler ultrasonography is a noninvasive imaging modality that is used to assess arterial and venous blood flow and any cavernosal fibrosis or calcification in penis to assess the reason behind erectile dysfunction.

Penile erection is a neurovascular phenomenon. Blood flow is critical for a man’s erections. When a man is sexually stimulated, the cavernosal smooth muscle relaxes, the arteries in his penis widen and the penis fills with blood.

This blood is what gives the penis the firmness it needs for sex. This leads to constriction of veins to the point that there is no flow going out of the veins. At the point of orgasm, there is no blood flowing in or out of the penis. When the stimulation stops, or when the man ejaculates, penile smooth muscle contracts, the veins widen again and allow blood to flow back into the body.

Many men with erectile function have problems with this blood flow. The arteries might not widen enough for sufficient blood to flow in or the veins might not constrict enough to keep the blood from flowing out. Both situations can lead to weak erections.

A base Penile Doppler ultrasound study is done when penis is flaccid and is done again after an injection with vasoactive drug. Results from the test are assessed to decide if the ED is of arteriogenic or venous origin.

A treatment plan may be recommended – like using vasoactive drug injections, P-shot.