What to Expect From a Transrectal Ultrasound

Reasons, preparation, expectations, risks, and side effects

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A transrectal ultrasound (TRUS) is used as a diagnostic or screening tool as a way to take images and assess organs and tissues inside the body. The procedure may also be referred to as a prostate sonogram (when used on men) or an endorectal ultrasound.

Doctor talking to patient in hospital room
Thomas Barwick / Getty Images

What Is It?

When it comes to imaging equipment, you may be most familiar with X-rays, which utilize radiation technology to produce pictures of internal structures in your body. But transrectal ultrasounds are unique in that they use high-energy sounds waves emitted from a probe that’s inserted into the rectum, as opposed to radiation.

The sound waves from the probe rebound off the surrounding organs and tissues, creating what’s known as an echo. The echoes then form computerized images of certain parts of the body, like the rectum, prostate (in men), ovaries (in women), and pelvic lymph glands. Your healthcare provider can view the images on a screen.

Ultrasound technology is considered safe and non-invasive, according to the Radiological Society of North America (RSNA). Depending on your situation, the ultrasound may be performed by a radiologist, urologist, or a radiology technician.

When It's Needed

There are a variety of signs, symptoms, and lab tests which may compel your healthcare provider to order this particular test to gather additional information about your situation. They include:

  • Having a rectal exam that may indicate prostate cancer
  • Receiving blood work that might point to prostate cancer
  • Assessing the condition of the prostate gland
  • Checking the female pelvic region when transvaginal ultrasounds aren’t viable options
  • Diagnosing certain cancers
  • Pinpointing the location of a tumor in the anus or rectum
  • Examining the size of a tumor
  • Assessing whether or not a tumor has spread to the lymph nodes or other tissues in the body
  • Determining if there’s a cause for fertility issues, such as cysts on the reproductive organs, of both men and women.

Additionally, TRUS may also be used by your healthcare provider to administer medical procedures such as:

  • Assisting in obtaining tissue samples of the prostate for a biopsy in men and may be fused with MRI prostate images done previously to permit a more accurate prostate biopsy.
  • Administering treatments for cancerous and noncancerous conditions like brachytherapy, high-intensity focused ultrasound (HIFU), or cryosurgery
  • Aspirating or draining abscesses


In the days leading up to the ultrasound, make sure your healthcare provider is aware of any allergies you have to medication.  It’s especially important to notify them of allergies you have to antibiotics.

Depending on the reason for your test, you may be asked to follow certain instructions to prepare for the exam. For example, if you’re taking certain medications, like blood thinners, you might be asked to discontinue them for a designated amount of time before your appointment.

Also, your healthcare provider might want you to have an enema prior to the test to clean out the rectum and colon.

What to Expect

On the day of the ultrasound, wear loose-fitting, comfortable clothing. You’ll likely be asked to remove all or part of your clothing, and you may be asked to wear a gown. Additionally, your healthcare provider might ask you to urinate so that you have an empty bladder before the test. A TRUS may include the following steps:

  • You may be asked to lie on your side and bend your knees towards your chest
  • The ultrasound probe, or sensor, is covered with a condom and lubricated with jelly
  • Generally, the probe is about the size of a finger
  • After it’s been covered with jelly, it’s inserted into the rectum where you may experience a pressure sensation similar to when you have a bowel movement
  • Once the healthcare provider or technician has positioned the probe in place, images of your internal tissues and organs will begin to appear on the screen
  • During the TRUS, the healthcare provider may collect a tissue sample for a biopsy

A typical TRUS takes between 15-30 minutes to complete. Your healthcare provider will provide you with any follow-up instructions you may need.

Risks and Side Effects

Transrectal ultrasounds provide a safe testing method to get images of what’s going on inside of your body while avoiding exposure to radiation. If the healthcare provider doesn’t do a biopsy during the test, most people won’t experience any side effects.

If the healthcare provider performs a biopsy, there may be some side effects like:

  • Rectal bleeding
  • Soreness and pain
  • Difficulty urinating or pain with urination
  • Blood in the urine
  • Blood in the semen
  • An infection

These side effects should subside within a few weeks following the procedure. If you experience lingering problems, be sure to talk with your healthcare provider.

A Word From Verywell

Transrectal ultrasounds may cause a minimal amount of discomfort similar to when your healthcare provider performs a rectal exam. If your practitioner does a biopsy during the ultrasound, you may experience a more intense sensation in the rectum each time they retrieve a sample. However, a numbing agent is used to put you more at ease when you have a biopsy. If you find that the TRUS is too painful, let your technician orhealthcare provider know so that they can try to make you more comfortable.

Generally, you should be able to engage in your usual activities following the TRUS, but you’ll want to follow any individualized recommendations your healthcare provider gives you. If you had a biopsy during the ultrasound, your practitioner would likely prescribe a course of antibiotics to reduce the risk of infection.  

2 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. Harvard Health Publishing. Biopsy of the Prostate and Transrectal Ultrasound.

  2. Canadian Cancer Society. Transrectal ultrasound (TRUS).

Additional Reading
  • Radiological Society of North America. Ultrasound — Prostate.

  • Vyas JB, Ganpule SA, Ganpule AP, Sabnis RB, Desai MR. Transrectal ultrasound-guided aspiration in the management of prostatic abscess: A single-center experience. The Indian Journal of Radiology and Imaging. 2013 Jul; 23(3):253-7. doi: 10.4103/0971-3026.120262.

By Jenny Lelwica Buttaccio, OTR/L
Jenny Lelwica Buttaccio, OTR/L, is a licensed occupational therapist and advocate for patients with Lyme disease.