Pelvic Ultrasound
Also Known As
Pelvic ultrasound (US) scanning, pelvic US imaging, pelvic ultrasonography or sonography.
Description
Ultrasound scans are high frequency sound waves too high for humans to
hear. After the Titanic hit an iceberg and sank in 1912, many people
researched ways to find underwater icebergs. During this time, SONAR
(sound navigation and ranging), which uses ultrasound, was developed.
Ultrasound waves sent to the part of the body being examined are
reflected, refracted, or absorbed at the interfaces inside the body.
Echoes that return in this way, carry information about the size, distance,
and uniformity of internal organs. This is displayed on a monitor to create
an ultrasound image.
Pelvic sonography is a useful way of examining pelvic organs, such as
the uterus, ovaries, fallopian tubes (uterine tubes), bladder in females;
and the prostate gland, seminal vesicles, and bladder in males. During
pregnancy, it is used to monitor the health and development of the
fetus/embryo (unborn baby in mother's womb).
During a pelvic sonography, a hand-held device called a "transducer",
is placed on the skin surface of the area being examined and is moved around.
This transducer generates ultrasound and sends it through the body. It also
detects the returning echoes and transmits them as electrical signals.
Because one transducer continuously generates many ultrasound waves while
detecting echoes, a real time image can be produced on a viewing monitor.
These images can be recorded on videotape or can be frozen and recorded on
to film.
Ultrasound is similar to audible sound in that it can pass through
water and human organs easily, but it can't pass through air or bone. So,
gel is applied to the skin to bridge the gap between the transducer and
the internal organs to more effectively send the ultrasound waves.
When taking a pelvic ultrasound, drink a lot of water to fill the bladder.
Normally the uterus and ovaries are behind the intestine and hard to see,
but a distended bladder pushes the intestine up and the uterus back,
spreading them out evenly and making the uterus and ovaries easy to see.
Advantages of this procedure
- Safe, painless, easy, fast, and widely available.
- No radiation.
- Real time imaging -- ultrasonography can be used to guide invasive
procedures such as biopsy, and to visualize bowel movement and blood flow.
- In case of an emergency, bedside sonography can be done without
special patient preparations.
Types of Pelvic Ultrasound
There are three types of pelvic ultrasound procedures:
1.Transabdominal (abdominal) ultrasound
While the patient is lying down, a transducer is placed on the lower
stomach allowing the uterus, ovaries, and pelvic organs to be seen through
a full bladder. The bladder must be full with urine, and resolution is low,
but a wide picture of the entire pelvis can be seen.
2.Transvaginal (endovaginal, vaginal) ultrasound
A protective cover and lubricating gel is placed on the end of a thin,
long transducer, which is inserted into the vagina to obtain US images.
As the transducer by-passes the intestine and is more closely positioned to
the pelvic organs, like the uterus and ovaries, better images can be
obtained. There is no need to fill the bladder for this exam.
3.Transrectal (rectal) ultrasound
A protective cover and lubricating gel is placed on the end of a thin,
long transducer, which is inserted into the rectum through the anus to
examine the prostate gland. Because the prostate gland is right in front
of the rectum, good images can be obtained through the transducer.
Doppler ultrasound can be done during each type of pelvic ultrasound
procedure, which provides additional information about blood flow, helps
diagnose blockages in pelvic blood vessels, and is used for examining ovarian
tumors. Transvaginal ultrasound with color doppler can be used for individuals
at high risk of developing ovarian cancer. Color doppler, duplex doppler and
power doppler are three different techniques of doppler ultrasound.
Conditions that benefit from this procedure
- Monitoring fetal development.
- Pelvic pain.
- Pelvic mass.
- Abnormal bleeding.
- Abnormal discharge.
- Menstrual problems.
- To guide invasive procedures such as a needle biopsy and withdrawal of fluid.
- To examine blood flow and reveal blockages, including atherosclerotic
plaque and blood clots, in the arteries and veins of the pelvis.
Common conditions revealed by this procedure
- Fibroids (myoma) of the uterus
- Cysts of the ovaries, uterus
- Ectopic pregnancy
- Infection
- Pelvic inflammatory diseases
- Abscess -- tubo-ovarian abscess, pelvic abscess
- Tumors, cancers of the ovaries, uterus
- Congenital anomaly
- Injury
- Stones in the bladder, urethra, lower ureters
- Lost IUD (intrauterine contraceptive device)
- Congenital anomalies, intrauterine growth retardation, death of the
fetus/embryo
- Complications of pregnancy -- spontaneous abortion, missed
abortion, threatened abortion, incomplete abortion
- Placental abnormality
- Hydatidiform mole
- Hyperplasia, cancer of prostate gland (in males)
- Tumor, inflammation of bladder
How this procedure is performed
You will need to remove your upper garments and put on a hospital gown.
You will then be positioned on an examination table on your back with your
hands above your head, and a lubricating gel will be applied to your pelvic
area. An apparatus, known as a transducer, will be placed on your pelvic
area and moved around to get real-time images.
If needed, a transvaginal ultrasound or transrectal ultrasound examination
may be added. If so, you will be asked to urinate completely and remove all
your lower garments. While lying down, a transducer will be inserted into
your vagina or rectum.
After the examination, the gel will be cleaned off and you can change
back into your clothes. The entire examinations usually take 10-30 minutes.
Preparation for this procedure
- Drink six glasses of water one to two hours prior to your exam, and
avoid urinating. A full bladder helps with visualization of the uterus,
ovaries, and bladder wall.
- Wear comfortable, loose-fitting clothing.
- Remove your upper garments before examination and put on a hospital gown.
- For transvaginal ultrasound or transrectal ultrasound examinations,
you need to remove lower garments and urinate before your exam and.
- In an emergency, bedside exams can be done without special preparations.
- Tell the sonographer, sonologist, or physician sonologist conducting the
examination about pain, bleeding, discharge, fever, or any other symptoms you
have. Telling the examiner about past ultrasounds and surgeries is also
helpful, and is sometimes crucial information.
Result of this procedure
The image recorded on film or videotape is interpreted and analyzed by a
radiologist (a physician specialist experienced in ultrasound and other
radiology exams). The official report is sent to the practitioner who requested
the examination, who will inform you of the results and will use them as a
reference in your evaluation and treatment.
Risk of this procedure
There is no known risk to humans from diagnostic ultrasound. Unlike
X-ray examinations, ultrasound does not use radiation.
Limitations of this procedure
- Ultrasound does not penetrate air or bone. So if an abnormality is
behind bowel gas, ribs, or calcified rib cartilage, it may not be discovered
via this procedure.
- There is a limitation to ultrasound's ability to reach deep into
the body. Because ultrasound is absorbed and reflected inside the body, only
some of the waves reach deep places farthest from the transducer. For example,
given two tumors of equal size, the tumor closest to the transducer will be
discovered more readily than the more distant one. Consequently, examinations
are not as productive for obese, tall patients as they are for thin or petite
ones.
- Ultrasonography is an operator-dependent, subjective test. The more
experienced the operator and the more closely the patient follows the operator's
instructions (e.g. 'hold your breath', 'do not eat', 'repress the urge to
urinate'), the better the results. Further, the more the operator knows about
the patient's past medical history, current medical history, and the results of
other radiological and laboratory tests, the better the examination. For best
results, before taking ultrasonography, ask if the practice where the scan is
being performed is accredited either by the American Institute of Ultrasound in
Medicine or the American College of Radiology.
- Not all abnormalities can be discovered with a pelvic
ultrasonography. For example, a PAP smear is a more sensitive test than
ultrasound in detecting cervical cancer. And when diagnosed with cervical
cancer, CT scans and MRI are more accurate than ultrasound in making plans for
treatment.
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