What is Pelvic Ultrasound Imaging?
Ultrasound imaging, also called ultrasound scanning or sonography, involves exposing part of the body to high-frequency sound waves to produce pictures of the inside of the body. Ultrasound exams do not use ionizing radiation (as used in X-rays. Because ultrasound images are captured in real-time, they can show the structure and movement of the body’s internal organs, as well as blood flowing through blood vessels.
Ultrasound imaging is a noninvasive medical test that helps physicians diagnose and treat medical conditions.
A pelvic ultrasound provides pictures of the structures and organs in the lower abdomen or pelvis.
Ultrasound Imaging of the Pelvis
There are three types of Pelvic Ultrasound:
- Vaginal (transvaginal) for women
- Rectal (transrectal) for men
- A Doppler ultrasound exam may be part of a pelvic ultrasound examination.
Common used of the procedure for Women
Pelvic ultrasound exams are used to monitor the health and development of an embryo or fetus during pregnancy.
Ultrasound examinations can also help diagnose symptoms experienced by women such as pelvic pain, abnormal bleeding, other menstrual problems and help to identify:
- palpable masses such as ovarian cysts and uterine fibroids.
- ovarian or uterine cancers.
A transvaginal ultrasound is usually performed to view the endometrium or the lining of the uterus, including its thickness, and the ovaries. Transvaginal ultrasound also affords a good way to evaluate the muscular walls of the uterus, called the myeometrium.
Sonohysterography allows for a more in-depth investigation of the uterine cavity. These exams are typically performed to detect:
- uterine anomalies
- uterine scars
- endometrial polyps
- cancer, especially in patients with abnormal uterine bleeding
Some physicians also use sonohysterography for patients with infertility.
Common uses of the procedure for Men
A pelvic or abdominal ultrasound is used to evaluate the:
- seminal vesicles
Transrectal ultrasound, a special study usually done to view the prostate gland, involves inserting a specialized ultrasound transducer into a man’s rectum.
In men and women, a pelvic ultrasound exam can help identify:
- kidney stones.
- bladder tumours.
- other disorders of the urinary bladder.
In children, pelvic or abdominal ultrasound can help evaluate:
- early or delayed puberty in girls
- pelvic pain
- ambiguous genitalia and anomalies of the pelvic organs
- pelvic masses in children
Doppler ultrasound images can help the physician to see and evaluate:
- blockages to blood flow (such as clots).
- narrowing of vessels (which may be caused by plaque).
- tumors and congenital malformation.
How should I prepare?
You should wear comfortable, loose-fitting clothing for your ultrasound exam. You may need to remove all clothing and jewelry in the area to be examined.
You may be asked to wear a gown during the procedure.
Transabdominal scans usually require you to drink 6 glasses of fluid an hour before your examination to ensure your bladder is full.
What does the equipment look like?
Ultrasound scanners consist of a console containing a computer and electronics, a video display screen and a transducer that is used to scan the body and blood vessels. The transducer is a small hand-held device that resembles a microphone, attached to the scanner by a cord. The transducer sends out high frequency sound waves into the body and then listens for the returning echoes from the tissues in the body.
The ultrasound image is immediately visible on a screen that looks much like a computer or television monitor. The image is created based on the amplitude (strength), frequency and time it takes for the sound signal to return from the patient to the transducer and the type of body structure the sound travels through.
For ultrasound procedures requiring insertion of the transducer, such as transvaginal or transrectal exams, the device is covered and lubricated.
How is the procedure performed?
For most ultrasound exams, the patient is positioned lying face-up on an examination table that can be tilted or moved.
A clear water-based gel is applied to the area of the body being studied to help the transducer make secure contact with the body and eliminate air pockets between the transducer and the skin. The sonographer (ultrasound technologist) or radiologist then presses the transducer firmly against the skin in various locations, sweeping over the area of interest or angling the sound beam from a farther location to better see an area of concern.
Transvaginal ultrasound is performed very much like a gynecologic exam and involves the insertion of the transducer into the vagina after the patient empties her bladder. The tip of the transducer is smaller than the standard speculum used when performing a Pap test. A protective cover is placed over the transducer, lubricated with a small amount of gel, and then inserted into the vagina.
Only two to three inches of the transducer end are inserted into the vagina. The images are obtained from different orientations to get the best views of the uterus and ovaries.
Transvaginal ultrasound is usually performed with the patient lying on her back, possibly with her feet in stirrups similar to a gynecologic exam.
What will I experience during and after the procedure?
Most ultrasound examinations are painless, fast and easy.
For a transabdominal exam:
After you are positioned on the examination table, the Radiologist or sonographer will apply some water-based gel on your skin and then place the transducer firmly against your body, moving it back and forth over the area of interest until the desired images are captured. There is usually no discomfort from pressure as the transducer is pressed against the area being examined.
If scanning is performed over an area of tenderness, you may feel pressure or minor pain from the transducer.
For a transvaginal exam:
With transvaginal ultrasound, although the examination is often performed to look for a cause of pelvic pain, the sonogram itself should not be painful or significantly increase your discomfort. A vaginal sonogram is usually more comfortable than a manual gynecologic examination.
For a transrectal exam:
If no biopsy is required, transrectal ultrasound of the prostate is similar or may have less discomfort than a rectal exam performed by your doctor.
- Most ultrasound scanning is noninvasive (no needles or injections) and is usually painless.
- Ultrasound is widely available, easy-to-use and less expensive than other imaging methods.
- Ultrasound imaging does not use any ionizing radiation.
- Ultrasound scanning gives a clear picture of soft tissues that do not show up well on x-ray images.
- Ultrasound is the preferred imaging modality for the diagnosis and monitoring of pregnant women and their unborn babies.
- Ultrasound provides real-time imaging, making it a good tool for guiding minimally invasive procedures such as needle biopsies and needle aspirations.
- Pelvic ultrasound can help to identify and evaluate a variety of urinary and reproductive system disorders in both sexes without even the minimal risks associated with x-ray exposure.
- For standard diagnostic ultrasounds there are no known harmful effects on humans.
What are the limitations of Pelvic Ultrasound Imaging?
- Ultrasound waves are disrupted by air or gas; therefore ultrasound is not an ideal imaging technique for the bowel or organs obscured by the bowel. In most cases, barium exams, CT scanning, and MRI are the methods of choice in this setting.
- Large patients are more difficult to image by ultrasound because tissue attenuates (weakens) the sound waves as they pass deeper into the body.