Transrectal Ultrasound

A transrectal ultrasound (TRUS) is a type of ultrasound that examines organs around your pelvis. Ultrasounds use sound waves to show your organs and tissues. A transrectal ultrasound is minimally invasive. In men, healthcare providers often use it to examine the prostate gland. In women, providers sometimes use it to look at pelvic and reproductive organs.

During a TRUS, your provider inserts a probe (transducer) into your anus. They gently guide it up to your rectum. The probe uses sound waves to create images that your provider can see.

Other common names for transrectal ultrasound (pronounced “tranz-REK-tl” “UHL-truh-sound”) include:

• Endorectal ultrasound (ERUS)
• Prostate sonogram
• Prostate ultrasound

When is it performed?

Healthcare providers may recommend a transrectal ultrasound if:

• You have problems peeing.
• You have difficulty getting pregnant.
• They notice something during a digital rectal exam.
• A blood test shows high PSA levels.
• You’re a woman with pelvic organ issues, but a transvaginal ultrasound isn’t an option.

What does it show?

A TRUS can show things like:

• An enlarged prostate
• Inflammation
• Cysts
• Tumors and other signs of cancer

How does a transrectal ultrasound work?

A transrectal ultrasound uses sound waves to create images. An ultrasound technician, a physician or another healthcare provider inserts the probe into your rectum. The probe releases sound waves that bounce off the surrounding areas. The sound waves travel back to the probe, which converts them to signals. The signals project images onto a video screen that your provider can look at.

What to expect before the test

Before a transrectal ultrasound, your provider will ask about your health history. Let them know if you have any:

• Allergies to medications
• Heart conditions
• Lung conditions
• History of surgery on your colon or rectum
• Conditions that affect your immune system

You should also let them know if you usually take antibiotics before a procedure.

What is the prep for a transrectal ultrasound?

Your healthcare provider will give you specific instructions. For example, they may ask you to:

• Avoid aspirin and nonsteroidal anti-inflammatory drugs (NSAIDs), like ibuprofen and naproxen.
• Stop taking blood thinners.

They may also ask you to have an enema one to four hours before TRUS. An enema helps clear poop and gas out of your colon and rectum. This makes it easier to guide the probe and get the best images. The pressure of the probe may cause you to feel like you need to pee. So, your provider may also ask you to pee before the test.

What to expect during the test

On the day of your transrectal ultrasound, you should wear comfortable clothing. You’ll need to remove some of your clothing or wear a hospital gown during the procedure.

During the TRUS:

1. You’ll lie on your side and bend your knees toward your chest.
2. Your healthcare provider will insert a lubricated probe into your anus. The probe is about the size of a finger. You’ll feel some pressure, which may feel like you’re pooping.
3. After your provider positions the probe, they’ll see the images of your organs and tissues on a video screen.

A TRUS usually takes less than 30 minutes.

In some cases, providers take a tissue sample (needle biopsy) during a TRUS. Tissue samples can help them diagnose conditions like an enlarged prostate, inflammation and different cancers. Providers most commonly take prostate tissue samples. But they may take samples from other organs, like the cervix.

What to expect after

You can go home after a transrectal ultrasound. Most people can drive themselves home. But check with your healthcare provider to make sure.

Your provider will give you follow-up instructions. You may need to:

• Avoid taking any aspirin or NSAIDs for at least three days after the TRUS.
• Take antibiotics as prescribed.
• Drink extra water to keep your urinary system clear.

Your provider will send the images to a radiologist, who will carefully review the images and make a diagnosis.

If you have a biopsy during the TRUS, your provider will send the sample to a lab. After the analysis, your provider will talk to you about your results.

What are the advantages and risks?

A transrectal ultrasound is minimally invasive and safe. This test:

• Doesn’t use radiation like other types of imaging tests do
• Gives clear images of soft tissues
• Produces images in real time

There aren’t any known TRUS risks or complications. You may have some discomfort.

But if you have a biopsy along with TRUS, some risks include:

• Blood in your semen (hematospermia)
• Blood in your pee (hematuria)
• Erectile dysfunction
• Infections
• Pain and soreness
• Pain or burning when you pee (dysuria)
• Rectal bleeding
• Difficulty peeing

How painful is it?

Unless you have symptoms in the area that cause pain, a TRUS typically doesn’t hurt. You can usually return to your normal activities right away. If you have an enlarged prostate, you may feel some mild pain or pressure. Your provider will check in with you during the procedure to make sure you’re OK.

If you have a biopsy during your TRUS, you may need to wait a few days to go back to your normal activities.

What type of results do you get and what do the results mean?

It depends on why you need a transrectal ultrasound. Sometimes, healthcare providers can easily diagnose a condition. Other times, they may need to order more tests, like an MRI, to help them make an official diagnosis.

Your provider will review your results with you and explain what they mean for your care.

When should I know the results?

A full report usually takes anywhere from a few hours to a few business days. It depends on how quickly a healthcare provider can examine your images. During your appointment, your provider will give you a better idea of when to expect the results.

If the results are abnormal, what are the next steps?

If your healthcare provider notices something unexpected, they may recommend more tests. They may also recommend treatment.

When should I call my doctor?

Talk to your healthcare provider if you have any of these symptoms after your transrectal ultrasound:

• A gel-like blob in your pee
• Bloody pee that doesn’t go away
• Bloody poop that doesn’t go away
• Fever
• Trouble peeing that doesn’t go away
• Pain that doesn’t go away with medication

Can transrectal ultrasound detect PCOS?

Yes. A transvaginal ultrasound is a more common way to detect polyendocrine metabolic ovarian syndrome (PMOS), formerly called polycystic ovarian syndrome (PCOS). But a transrectal ultrasound is just as effective at detecting this condition.