A Transrectal Ultrasound Scan (TRUS) is a type of diagnostic imaging test that uses high-frequency sound waves (ultrasound) to create real-time pictures of the prostate gland and nearby structures. The ultrasound probe is gently placed into the rectum (a rectal scan approach) because the rectum sits directly behind the prostate, allowing clearer, more detailed images than an ultrasound done over the lower abdomen.

TRUS helps a clinician evaluate the size and shape of the prostate, look for areas that appear abnormal (such as suspicious nodules or changes that may need tumor assessment), and guide procedures like a prostate biopsy. In many cases, TRUS is performed specifically to guide biopsy needles to the correct part of the prostate.

What the results mean (in plain language): TRUS results are usually described as “normal” or showing findings such as an enlarged prostate, inflammation, calcifications, cysts, or a suspicious area that may require further testing. Importantly, ultrasound images alone often cannot confirm prostate cancer. TRUS can identify areas that look unusual, but a biopsy (tissue sampling) is typically needed to confirm or rule out cancer. Your report may also include an estimated prostate volume (size), which can help explain urinary symptoms and guide treatment choices.

TRUS is commonly ordered in men’s health care when a clinician needs a closer look at the prostate or needs imaging to guide a procedure. It may be recommended based on symptoms, physical exam findings, or blood test results.

A doctor may order a TRUS if you have:

• Urinary symptoms such as a weak stream, difficulty starting urination, frequent urination (especially at night), urgency, or a feeling of incomplete bladder emptying—symptoms often linked to benign prostatic hyperplasia (BPH) or other prostate conditions.
• An abnormal digital rectal exam (DRE) (for example, a lump, firmness, or unevenness felt on the prostate).
• An elevated or rising PSA (prostate-specific antigen) blood test, especially when deciding whether a prostate biopsy is needed.
• Blood in the urine or semen, pelvic discomfort, or symptoms suggesting prostatitis (prostate inflammation/infection).
• Need for biopsy guidance to sample prostate tissue to evaluate for prostate cancer.
• Follow-up of known prostate issues, such as monitoring prostate size or evaluating prior abnormal findings.

TRUS may also be used to assist with certain treatments and procedures, such as drainage of a prostate abscess, planning for some prostate therapies, or evaluating the prostate when other imaging is not available.

• Benign prostatic hyperplasia (BPH) (enlarged prostate)
• Prostate cancer
• Prostatitis (inflammation or infection of the prostate)
• Prostate abscess (a pocket of infection, less common)
• Prostatic cysts and benign nodules
• Prostate calcifications (small calcium deposits)
• Elevated PSA requiring further evaluation
• Lower urinary tract obstruction related to prostate enlargement

• Prostate cancer evaluation: supporting decisions about biopsy and helping target suspicious areas during a TRUS-guided biopsy
• Managing urinary symptoms: assessing prostate size and anatomy to guide treatment for an enlarged prostate (BPH)
• Monitoring men’s health: follow-up imaging when PSA changes or prostate exam findings raise concern
• Clarifying the cause of pelvic or prostate-related pain: helping evaluate possible prostatitis or other prostate abnormalities
• Procedure guidance: improving accuracy and safety when prostate tissue sampling or other prostate procedures are needed