Transrectal Ultrasound (TRUS)

What is a TRUS?

In this procedure, the doctor or technician inserts a probe slightly larger than a pen into your rectum. The probe directs high-frequency sound waves and the echo patterns form an image of the organs on a monitor. The image shows irregularities, but cannot definitively identify tumors. TRUS may also be used to obtain a biopsy where the doctor guides a needle to the correct spot to collect a tissue sample.

Before the Procedure

There is no preparation for this test, although some doctors will ask that you use an enema before the test to empty your rectum of stool. Tell your doctor if you have any allergies, especially to antibiotics.

During the Procedure

The procedure usually takes about 15-25 minutes

  • You will be asked to lie on your left side to allow for easier insertion of the rectal probe.
  • The probe will be coated with a clear lubricating jelly to allow for easier insertion into the rectum
  • The technician will adjust the console on the ultrasound machine to get a baseline for normal tissue.
  • When the sensor is put into the rectum, you will feel some pressure that resembles the feeling you have before a bowel movement.


If any suspicious areas are seen, several small biopsies will be taken through the wall of your rectum. The doctors will generally need to take up to six biopsies, depending on your condition. After the biopsy, you will be given two days worth of antibiotics. Your first dose will be given at the time of the procedure. There is a minimal amount of discomfort associated with the biopsy.

After the Procedure

There is usually some ongoing bleeding from both your rectum and in your urine, though this is usually very small and stops within a few days. It is important that you take your antibiotics as directed until they are completed.