Penile Doppler ultrasound scan

Ultrasound uses high frequency sound waves to create an image of an area of the body. 

This is a widely used diagnostic test to examine and measure the blood flow into your penis which could be causing erectile dysfunction (ED). Erectile dysfunction can have many causes, including not enough blood flowing into the penis (inflow ED), or blood becoming trapped in the penis (outflow ED). 

A penile Doppler scan can help to find the cause of a problem and can also be used to monitor an existing condition. 

The ultrasound is carried out by a sonographer or radiologist, both are trained professionals in this type of scan. 

How to prepare

You do not need a full bladder for your scan. 

You can continue to take any medicines prescribed by your doctor.

You should wear comfortable, loose-fitting clothing for your scan.

If you need a hoist (piece of medical equipment to help lift or move you safely), transport or a translator, please contact the radiology department.


A penile Doppler scan is a very safe procedure.

After the procedure you might still have an erection, but this should go down within 1 to 2 hours. There is a small risk (up to 2 in 100 patients) of a persistent painful erection (priapism), which could be serious. 

If you still have a rigid or painful erection 2 hours after the injection, please come back to the radiology or urology department where you will be seen.

Other treatment options

There are no other, less invasive, ways of getting this information.

The sonographer or radiologist will explain the procedure and ask you if you are happy for the scan to go ahead. If you decide to go ahead, you will be asked to sign a consent form. This states that you understand what it involves and agree to have the treatment. 

If you do not wish to have the scan or are undecided, please tell us. You can ask any questions before, during or after your scan. It is your decision and you can change your mind at any time. However not having the scan may delay your diagnosis as the doctors may not have all of the information that they need. 

A chaperone will be present for all intimate scans. You are welcome to bring a friend or family member to be present throughout the scan if you wish. 

Students or trainees may be present during the examination but only with your verbal consent. 

You can read more about our consent process.

During a penile Doppler scan

Your appointment is usually booked for 30 minutes. The scan itself usually takes a few minutes. This may vary depending on how clear the pictures are.

While we try to make sure that appointment times are kept, sometimes emergencies may need to take priority. We will inform you of any delays. Please be patient, but feel free to ask staff if you think you have been overlooked. 

You should allow 1 hour in total for your appointment.

  • You will be asked to undress from the waist down and lie down on a couch. 
  • We will cover you with a sheet. 
  • We will use paper tissue to cover your clothing to protect it from the gel.
  • A very small needle will be used to inject a ‘vasodilator’ medicine into the side of your penis. This drug widens the blood vessels and increases the blood flow to your penis, and you might get an erection (of varying degree) after the injection.
  • We use an ultrasound probe and apply a small amount of lubricating gel to the probe. 
  • The probe is then placed onto your penis. You might hear some swishing sounds coming from the ultrasound machine. This is the sound of blood flow in the penis.
  • Once the scan is completed, we will give you tissue to wipe away the gel and you can put your clothes back on.
  • The lights in the room will be dimmed so that the pictures on the screen can be seen more clearly. 
  • Selected images will be recorded so that they can be viewed later. 


Unless you are already in pain due to your symptoms, a penile Doppler ultrasound scan does not cause any pain. It might feel slightly uncomfortable but it should not hurt.


Your scan will be reviewed and most often reported on the same day. The results will be sent back to your doctor who will discuss the report with you.

If your referring doctor is your GP then you should make an appointment for 2 weeks after your scan to discuss the results.

If your referring doctor is a consultant at Guy’s and St Thomas’ then you should have an outpatient appointment arranged. If not, please contact them to arrange a time to talk about the results and any treatment you may need.

Resource number: 4659/VER3
Published date: March 2024
Review date: March 2027

Trusted Information Creator. Patient Information Forum

Contact us

If you have any questions or concerns about your ultrasound scan, please contact the Radiology Department

Phone: 020 7188 5490 Monday to Friday, 9am to 5pm

  • choose option 1 to cancel and not rebook an appointment
  • choose option 2 to reschedule or book a new appointment
  • choose option 3 for results
  • choose option 4 for patient transport
  • choose option 5 for general enquiries

Do you have any comments or concerns about your care?

Contact our Patient Advice and Liaison Service (PALS)

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