Prostate Ultrasound: What It Is & When It's Recommended

A prostate ultrasound is an imaging test used to check the health of the prostate, seminal vesicles, and bladder. It can help identify changes or lesions that may suggest prostatitis, benign prostatic hyperplasia, or prostate cancer.

This exam is mainly recommended when a doctor finds changes in the prostate during a digital rectal exam or when PSA test results are abnormal. It may also be ordered if symptoms of a prostate problem are present, such as difficulty urinating or a weak urine stream.

A prostate ultrasound can be done through the abdomen or rectum. The results should always be interpreted by a doctor.

What it checks for

A prostate ultrasound is used to evaluate the location, size, and shape of the prostate, as well as the seminal vesicles and bladder.

This exam can help identify signs of inflammation or infection in the prostate, known as prostatitis. It can also show calcifications, stones, cysts, nodules, or signs that may suggest prostate cancer.

In addition, this test can help investigate symptoms of prostate problems, such as difficulty urinating or a weak urine stream.

A prostate ultrasound is usually ordered after a clinical evaluation, which may include a digital rectal exam and PSA testing. It is typically performed by a radiologist or a trained sonographer and is a simple, well-tolerated test, although the transrectal approach may cause mild discomfort.

Indications for the exam

A prostate ultrasound may be indicated in the following situations:

• Prostate changes found during a digital rectal exam

• Elevated PSA

• To help diagnose male infertility

• To guide needle placement during a prostate biopsy

• To check the stage of prostate cancer

• To evaluate benign prostatic hyperplasia (enlarged prostate) or recovery after surgery

In addition, this exam may be recommended to help identify the cause of symptoms such as difficulty urinating, weak urine stream, increased urinary frequency, blood in the urine or semen, or testicle pain.

According to the American Cancer Society, if a PSA blood test, digital rectal exam, or other test results suggest prostate cancer, a prostate biopsy is usually needed to confirm the diagnosis.

Based on the results, the urologist can assess the risk of prostate issues or determine whether a current treatment is working.

How to prepare

Preparation for a prostate ultrasound depends on the type of ultrasound being performed.

For an abdominal prostate ultrasound, you may be asked to drink several glasses of water 1 to 2 hours before the exam and avoid urinating. This helps ensure the bladder is full during the test.

For a transrectal prostate ultrasound, your doctor may recommend bowel preparation, such as using a laxative or an enema before the exam. In some cases, an enema with water or a prepared solution is used a few hours before the test to improve image quality.

In addition, for a transrectal ultrasound, your doctor may ask you to temporarily stop taking anticoagulants and may prescribe antibiotics if a prostate biopsy is planned.

What to expect

The way a prostate ultrasound is done depends on the type of exam. The main types are:

1. Abdominal prostate ultrasound

An abdominal prostate ultrasound is done by applying gel to the lower abdomen, above the pubic area. The ultrasound probe is then placed on the skin to capture images of the prostate, which are sent to a computer.

This type of ultrasound can evaluate the shape and volume of the prostate. It can also measure the amount of urine left in the bladder after the person is asked to urinate, known as post-void residual urine.

2. Transrectal prostate ultrasound

A transrectal prostate ultrasound is done with the person lying on their left side with their legs bent. A lubricant is applied, and the ultrasound probe is inserted into the rectum, since the prostate is located between the rectum and bladder.

This allows images of the prostate gland to be obtained and helps the doctor check for any signs of changes.

This exam is simple, but it can be uncomfortable, especially if the person has hemorrhoids or anal fissures. In these cases, a local anesthetic may be applied to reduce discomfort.

If a prostate biopsy is planned, sedation is given and prostate samples are collected for laboratory analysis.

Interpreting results

The results of a prostate ultrasound should be interpreted by a doctor, along with any other requested tests.

If a transrectal prostate ultrasound with biopsy shows cell changes that may indicate cancer, the doctor will refer the patient to an oncologist. The oncologist can then recommend the most appropriate treatment.