What is a prostate/rectal ultrasound?

A prostate or rectal ultrasound is an imaging test that uses sound waves to look at your prostate or your rectum.

The healthcare provider uses a small probe called a transducer to make the images of your prostate or rectum. The transducer is about the size of a finger. It is gently placed into your rectum, where it sends out sound waves that bounce off your organs and other structures. The sound waves are too high-pitched for you to hear. The transducer then picks up the bounced sound waves. These are made into pictures of your organs.

Your provider can add another device called a Doppler probe to the transducer. This probe lets your provider hear the sound waves the transducer sends out. He or she can hear how fast blood is flowing through a blood vessel and in which direction it is flowing. No sound or a faint sound may mean that you have a blockage in the flow.

Why might I need a prostate/rectal ultrasound?

A prostate/rectal ultrasound may be used to check the size, location, and shape of the prostate gland and nearby structures. It may be used to look at the prostate gland for signs of cancer or other conditions. It’s often the next step after a finding of raised (elevated) prostate-specific antigen (PSA) during a blood test. Prostate/rectal ultrasound may be used to stage and watch treatment of rectal cancer. It is also used to look at the rectum for other problems.

Your healthcare provider may also use a prostate/rectal ultrasound to help place a needle to take a tissue sample (biopsy) . Or he or she may use it to help place radiation seeds used to treat prostate cancer.

Your provider may also use the test to see how well blood is flowing to the prostate or find masses.

Your provider may have other reasons to recommend a prostate/rectal ultrasound.

What are the risks of a prostate/rectal ultrasound?

An ultrasound has no risk from radiation. Most people have mild discomfort from the transducer being placed in the rectum.

Tell your healthcare provider if you are allergic to latex. The probe is placed in a latex covering before it is put into the rectum.

You may have risks depending on your specific health condition. Be certain your healthcare provider knows about all of your health conditions before the procedure.

Too much stool in the rectum may make the test less accurate.

How do I get ready for a prostate/rectal ultrasound?

• Your healthcare provider will explain the procedure and you can ask questions. Make a list of questions and any concerns with your healthcare provider before the procedure. Consider bringing a family member or trusted friend to the medical appointment to help you remember your questions and concerns.

• You may be asked to sign a consent form that gives your permission to do the procedure. Read the form carefully and ask questions if something is not clear.

• You may be asked to stop taking blood-thinning medicines, such as aspirin, for a week or so before the test if it is being done as part of a biopsy.

• You usually do not need to stop eating or drinking before the test. You also usually will not need medicine to help you relax (sedation).

• You may be given a small enema before the test.

• Follow any other instructions your provider gives you to get ready.

What happens during a prostate/rectal ultrasound?

You may have a prostate/rectal ultrasound done as an outpatient or during a hospital stay. The way the test is done may vary depending on your condition and your healthcare provider's practices.

Generally, a prostate/rectal ultrasound follows this process:

1. You will need to remove any clothing, jewelry, or other objects that may get in the way of the procedure.

2. If asked to remove clothing, you will be given a gown to wear.

3. You will lie on an exam table on your left side with your knees bent up to your chest.

4. The healthcare provider may do a digital rectal exam before the ultrasound.

5. The provider puts a clear gel on the transducer and puts the probe into the rectum. You may feel a fullness of the rectum at this time.

6. The provider will turn the transducer slightly several times to see different parts of the prostate gland and other structures.

7. If blood flow is being looked at, you may hear a whoosh, whoosh sound when the Doppler probe is used.

8. Once the test is done, the provider will wipe off the gel.

A prostate/rectal ultrasound may be uncomfortable and you will need to remain still during the test. The gel will also feel cool and wet. The technologist will use all possible comfort measures and do the scan as quickly as possible to minimize any discomfort.

What happens after a prostate/rectal ultrasound?

You don't need any special care after a prostate/rectal ultrasound. You may go back to your usual diet and activities unless your healthcare provider tells you otherwise.