Erectile Dysfunction Health Center

Doppler ultrasound (also called color duplex Doppler) uses a handheld tool passed lightly over the penis. The tool uses reflected sound waves to estimate the speed and direction of blood as it flows through a blood vessel. The sound waves go to a computer that changes the sounds to colors that are overlaid on a picture of the blood vessel. This shows the speed and direction of blood flow. You may need to have medicine injected into your penis (intracavernosal injection) to cause an erection before the Doppler test is done.

The results of your tests may show which kind of treatment is a good choice for you. For more information, see:

Erection Problems: Should I Take Medicine?

Erection Problems: Should I Try Injection Treatments?

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Why It Is Done

Tests for erection problems are done to help find whether the cause of an erection problem is physical, psychological, or a combination of both.

Physical conditions that may cause erection problems include:

• Problems with the nerves of the penis. Conditions such as multiple sclerosis or diabetes may cause nerve damage that affects a man's ability to have an erection. Also, surgery, injury, or radiation treatment to the pelvic area may cause damage to the nerves of the penis.
• Problems with the blood vessels that supply blood to the penis. Conditions such as hardening of the arteries (atherosclerosis) may make it difficult for a man to have an erection. Activities such as long-distance bicycle riding on a hard, narrow saddle may increase a man's risk for having an erection problem. See a picture of blood supply to the penis .
• Low levels of hormones, such as testosterone or thyroid hormones.
• Side effects of medicines, such as medicines taken for high blood pressure (hypertension) or depression.
• The use of tobacco, alcohol, or illegal drugs.

Psychological tests may be needed if no physical cause is found for an erection problem. Psychological causes of erection problems may include:

• Anxiety about sexual performance.
• Relationship problems.
• Stress.
• Depression or grief.

How To Prepare

Nocturnal penile tumescence (NPT) test

Do not take any medicines that cause an erection, such as sildenafil (Viagra), tadalafil (Cialis), and vardenafil (Levitra), before the test.

Do not drink alcohol or take sleeping pills for 2 days before you have a nocturnal penile tumescence (NPT) test. The alcohol and the pills can change your deep (REM) sleep time, which can affect nocturnal erections.

Intracavernosal injection test

If you are having an intracavernosal injection test, tell your doctor if you:

• Are allergic to any medicine.
• Have any bleeding problems or are taking blood-thinning medicine, such as aspirin or other nonsteroidal anti-inflammatory drugs (NSAIDs), warfarin (Coumadin), clopidogrel (Plavix), or ticlopidine (Ticlid).
• Have ever had an erection lasting more than 3 hours (priapism).

Doppler ultrasound

You may be asked to avoid products that contain nicotine (cigarettes, chewing tobacco) for 30 minutes to 2 hours before the test.