Transrectal ultrasound (TRUS)
A transrectal ultrasound (TRUS) may also be called prostate sonogram or endorectal ultrasound. It is used to look at the prostate and tissues around it. An ultrasound transducer (also called a probe) sends sound waves through the wall of the rectum and into the prostate and surrounding tissue. A computer analyzes the wave patterns (called echoes) as they bounce off the organs and converts them into an image that doctors view on a video screen.
Why a TRUS is done
A TRUS is often used to help diagnose prostate cancer if the prostate-specific antigen (PSA) level is high, the doctor feels an abnormal area during a digital rectal exam (DRE) or a man has certain symptoms, such as trouble urinating. TRUS is done to:
- look for abnormal areas in the prostate
- guide a needle during a biopsy to collect samples from the prostate
- look at the size and shape of the prostate
A TRUS can also be used to find out what is causing infertility, such as cysts in a man’s reproductive system.
A TRUS can also be used to deliver treatments for cancerous and non-cancerous conditions of the prostate or surrounding structures. For example, doctors can use a TRUS to place an implant for brachytherapy, deliver high-intensity focused ultrasound (HIFU) or do cryosurgery.
How a TRUS is done
A TRUS is usually done in a doctor’s office, clinic or hospital. The test usually takes 15–30 minutes and you can go home the same day.
Some special preparation is needed before you have a TRUS. If you take certain medicines that thin the blood, your doctor will tell you to stop taking them 7–10 days before the test. You will be given an enema 1–4 hours before the procedure to help clean out the colon and rectum. Just before the procedure, the healthcare team may ask you to urinate to empty your bladder.
During the test, you’ll likely be asked to lie on your side with your knees bent toward your chest. The doctor puts a protective cover and lubricant on the ultrasound probe. The doctor then passes the probe, which is about the width of a finger, into the rectum. You may feel pressure or have a sensation of fullness in the rectum when the transducer is in place.
Sometimes doctors will use a TRUS to help them do a core biopsy to collect samples from the prostate.