Prostate Ultrasound (TRUS): What Men Should Know About This Diagnostic Tool

At Independent Physicians Medical Center (IPMC) in Northeast Philadelphia, we offer prostate ultrasound imaging with professionalism and privacy in our comfortable outpatient facility.

What Is a Prostate Ultrasound?

A transrectal ultrasound (TRUS) uses a small, specially designed transducer that is gently inserted into the rectum. Because the prostate gland sits directly in front of the rectum, this approach provides much clearer and more detailed images than scanning through the abdomen.

The ultrasound shows the size and volume of the prostate (important for treatment planning), the internal structure (zonal anatomy, including the peripheral zone where most cancers develop), any nodules, masses, or areas of abnormal echogenicity, the seminal vesicles, and the surrounding tissues.

TRUS is also the standard technique used to guide prostate biopsies — the real-time ultrasound image shows the needle’s exact position as tissue samples are collected from specific areas of the prostate.

Why Would Your Doctor Order a Prostate Ultrasound?

Your doctor may recommend a prostate ultrasound if you have:

• Elevated PSA (prostate-specific antigen) levels that need further investigation
• An abnormal digital rectal exam (DRE) with a suspicious area of firmness or nodularity
• A need for prostate biopsy — TRUS guides the biopsy needles to specific areas of the prostate for tissue sampling. Newer approaches may use MRI/ultrasound fusion, where MRI images are overlaid on the real-time TRUS to target suspicious areas identified on MRI
• Urinary symptoms such as difficulty urinating, weak stream, frequent urination, nocturia (waking at night to urinate), or urinary retention — which may suggest benign prostatic hyperplasia (BPH, or enlarged prostate)
• Pelvic pain or discomfort that may be related to the prostate
• Suspected prostatitis (infection or inflammation of the prostate)
• Prostate volume measurement — needed for treatment planning in BPH (to determine candidacy for certain medications or surgical procedures) and for calculating PSA density (PSA level relative to prostate size)
• Infertility evaluation — assessing the prostate and seminal vesicles as part of a male fertility workup
• Post-treatment monitoring — following prostate cancer treatment to check for local recurrence

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How to Prepare and What to Expect

Your doctor may recommend a small enema (Fleet enema) 1-2 hours before the exam to empty the rectum, which improves image quality and comfort. You should also inform your doctor if you take blood thinners, as these may need to be adjusted if a biopsy is planned.

You’ll lie on your left side with your knees drawn toward your chest. The sonographer or doctor gently inserts the lubricated, sheath-covered transducer into the rectum. The transducer is about the width of a finger. While you may feel pressure and mild discomfort, the exam should not be painful. The transducer is moved gently to capture images from different angles.

The imaging portion typically takes 15 to 30 minutes. If a biopsy is being performed simultaneously, the procedure will take longer. You may feel brief sharp sensations during biopsy needle sampling, and local anesthesia is usually provided.

After the exam, you can resume normal activities. You may notice a small amount of rectal spotting, which is normal. A board-certified radiologist will review the images and send a report to your urologist or referring doctor.