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What is a prostate/rectal sonogram?
A prostate/rectal sonogram is a noninvasive (the skin is not pierced) procedure used to assess the size, shape, and location of the prostate gland and to assess the rectum. A sonogram uses ultrasound technology to allow quick visualization of the prostate and related structures from outside the body.
A prostate/rectal sonogram uses a handheld probe called a transducer that sends out ultrasonic sound waves at a frequency too high to be heard. When the transducer is placed on the skin at certain locations and angles, the ultrasonic sound waves move through the skin and other body tissues to organs and structures within the body. The sound waves bounce off the organs like an echo and return to the transducer. The transducer picks up the reflected waves, which are then converted into an electronic picture of the organs.
Different types of body tissues affect the speed at which sound waves travel. Sound travels the fastest through bone tissue and moves most slowly through air. The speed at which the sound waves are returned to the transducer, as well as how much of the sound wave returns, is translated by the transducer as different types of tissue.
Prior to the procedure, clear, water-based gel is applied to the skin to allow for smooth movement of the transducer over the skin and to eliminate air between the skin and the transducer.
By using an additional mode of ultrasound technology during an ultrasound procedure, blood flow to the prostate gland can be assessed. An ultrasound transducer capable of assessing blood flow contains a Doppler probe. The Doppler probe within the transducer evaluates the velocity and direction of blood flow in a blood vessel by making the sound waves audible. The degree of loudness of the audible sound waves indicates the rate of blood flow within a blood vessel. Absence or faintness of these sounds may indicate an obstruction of blood flow.
Related procedures that may be performed to evaluate the prostate gland and rectum include prostate biopsy and sigmoidoscopy. Please see these procedures for more information.
What is the prostate gland?
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The prostate gland is about the size of a walnut and surrounds the neck of a man’s bladder and urethra—the tube that carries urine from the bladder. It is partly muscular and partly glandular, with ducts opening into the prostatic portion of the urethra. It is made up of three lobes: a center lobe with one lobe on each side.
As part of the male reproductive system, the prostate gland’s primary function is to secrete a slightly alkaline fluid that forms part of the seminal fluid (semen), a fluid that carries sperm. During male climax (orgasm), the muscular glands of the prostate help to propel the prostate fluid, in addition to sperm that was produced in the testicles, into the urethra. The semen then travels through the tip of the penis during ejaculation.
A prostate/rectal sonogram may be used to assess the size, location, and shape of the prostate gland and nearby structures. A sonogram may be used to examine the prostate gland for evidence of cancer. This procedure may be performed after a finding of elevated prostate-specific antigen (PSA) during a blood test. Prostate/rectal sonography may be used to stage rectal cancer, monitor the treatment of rectal cancer, and to assess the rectum for other problems.
A prostate/rectal sonogram may be performed to assist in placement of needles used to biopsy (obtain a tissue sample) the prostate, or to aid in the placement of radiation “seeds” used to treat prostate cancer.
This procedure may also be used to assess blood flow to the prostate or other masses that may be located during the procedure.
There may be other reasons for your physician to recommend a prostate/rectal sonogram.
There is no radiation used and generally no discomfort from the application of the ultrasound transducer to the skin. There will be some discomfort associated with inserting the transducer into the rectum.
The sonogram transducer will be covered in a latex condom-like covering prior to insertion into the rectum. Therefore, the test is contraindicated for patients with a latex allergy.
There may be other risks depending upon your specific medical condition. Be sure to discuss any concerns with your physician prior to the procedure.
Excess stool in the rectum may interfere with the results of the test.
- Your physician will explain the procedure to you and offer you the opportunity to ask any questions that you might have about the procedure.
- You may be asked to sign a consent form that gives your permission to do the procedure. Read the form carefully and ask questions if something is not clear.
- Generally, no prior fasting or sedation is required.
- You may be given a small enema prior to the procedure.
- Based upon your medical condition, your physician may request other specific preparation.
A prostate/rectal sonogram may be performed on an outpatient basis or as part of your stay in a hospital. Procedures may vary depending on your condition and your physician's practices.
Generally, a prostate/rectal sonogram follows this process:
- You will be asked to remove any clothing, jewelry, or other objects that may interfere with the procedure.
- If asked to remove clothing, you will be given a gown to wear.
- You will lie on an examination table on your left side with your knees bent up to your chest.
- The physician may perform a digital rectal examination before the sonogram procedure.
- The transducer will be lubricated with a clear gel and inserted into the rectum. You may experience a feeling of fullness of the rectum at this time.
- The transducer will be rotated slightly several times during the procedure in order to obtain adequate visualization of the prostate gland and other structures.
- If blood flow is being assessed, you may hear a "whoosh, whoosh" sound when the Doppler probe is used.
- Once the procedure has been completed, the gel will be wiped off.
While the prostate/rectal sonogram procedure itself causes no pain, having to lie still for the length of the procedure may cause slight discomfort, and the clear gel will feel cool and wet. The technologist will use all possible comfort measures and complete the procedure as quickly as possible to minimize any discomfort.
There is no special type of care required after a prostate/rectal sonogram. You may resume your usual diet and activities unless your physician advises you differently.