Ultrasound imaging - also known as sonography - uses sound waves to produce
images of organs, vessels and tissues in the body. During an ultrasound examination, a small, hand-held transducer is placed
in contact with the patient's body. It emits inaudible, high-frequency sound
waves that pass through the body, sending back "echoes" as they bounce off
organs, vessel walls and tissues. Special computer equipment then converts these
echoes into an image.
Ultrasound imaging has many applications. It is ideal for imaging the heart
and the blood vessels. It can evaluate heart wall, chamber and valve motion, as
well as blood flow within the heart and blood vessels. It may be used to detect
breast cysts or gallstones and to examine the prostate and to examine the liver,
kidneys, pancreas, spleen, colon and urinary bladder for tumors, inflammation,
stones or cysts. The use of ultrasound is expanding into the field of sports
medicine as an effective way to detect ligament, tendon and nerve injuries.
Ultrasound also can be used to guide needle placement for biopsies, and to guide
the drainage of cysts or fluid collections in the abdomen or chest that occur
with some illnesses.
Because ultrasound uses sound waves instead of radiation to create images, it
is a safe form of fetal imaging. It is used in obstetrics to assess fetal
well-being, determine fetal position, diagnose multiple gestations (twins,
triplets, etc.), determine a delivery date and rule out ectopic pregnancy. If
the fetus is old enough and positioned correctly, a baby's sex also can be
determined. Ultrasound also plays a significant role in the evaluation and
treatment of infertility.
In addition to its diagnostic imaging capabilities, ultrasound also is
sometimes used in therapeutic applications to help treat soft tissue injuries.
The discussion contained here, however, is confined to medical imaging.
Depending upon the body part being examined, you may be advised to drink
water before your ultrasound examination, because sound waves travel more easily
through fluid. You also may be advised to avoid drinking carbonated beverages
before the examination because the air bubbles may interfere with the image.
You should wear comfortable clothing on the day of your examination. You may
or may not be asked to put on a hospital gown, depending upon the procedure.
Before the exam begins, a sonographer will explain the procedure to you, ask
questions about your health, ask why your physician requested the exam, and
answer any questions you might have. A sonographer is a skilled medical
professional who has received specialized education in the areas of anatomy,
patient care, imaging techniques and ultrasound procedures.
During the Examination
Total examination time can range from less than 30 minutes to more than an
hour, depending upon the part of the body being examined.
The sonographer will position you on the examination table and apply a
special lotion to your skin directly above the area being studied. The lotion is
odorless, harmless and water-soluble. It acts as a conductor, making it easier
for sound waves to travel into the underlying anatomy. After the lotion is
applied, the sonographer will move a device called a transducer over the
lotion-covered skin. The transducer sends out sound waves and receives echoes.
These echoes are relayed to a computer for processing and displayed on a monitor
as a picture for the sonographer to view. Selected pictures will be saved on
paper, film, videotape or in a computerized format to be reviewed by the
During the procedure, you will feel light pressure from the transducer being
moved over your skin. The sonographer may ask you to change the position of your
body or to hold your breath for a few seconds so that certain images can be
When the exam is complete, your ultrasound scans will be given to a
radiologist - a physician who specializes in the diagnostic interpretation of
medical images. Other physicians who may obtain additional training and read
ultrasound exams include obstetricians, gynecologists, cardiologists, vascular
surgeons, oncologists and urologists.
Other Types of Ultrasound Procedures
Echocardiography uses ultrasound to take "moving pictures" of the heart.
During an echocardiography examination, you will be hooked up to an
electrocardiogram unit (ECG) that monitors the timing of events in the heart.
The ECG leads will be attached to your chest with small adhesive patches and
wires. The sonographer will spread gel on your chest and then move the
ultrasound transducer over your chest wall or upper abdomen to obtain images of
your heart. To evaluate the heart's response to stress, you might also be asked
to perform a series of exercises that elevate your heart rate. Another
echocardiography examination will be performed while your heart rate is
Doppler ultrasound is a special application of ultrasound that detects moving
objects, such as blood flow. With Doppler ultrasound, physicians can examine the
amount, direction and speed of blood flowing to the brain or coursing through
the heart, vessels or other organs.
Although the ultrasound transducer usually is placed on the outside of the
body, on the surface of the skin, a few examinations require that the transducer
be placed inside the body to obtain the highest quality images. Some types of
gynecological and obstetric examinations, for example, require that the
transducer be placed inside the vagina. These examinations, called endovaginal
or transvaginal procedures, use a special type of transducer designed for
maximum image quality and minimum patient discomfort.
During a transesophageal echocardiogram, the transducer is threaded down a
patient's throat into his or her esophagus. Placement of the transducer in the
esophagus permits the sonographer to obtain clear images of specific areas of
A rectal transducer is used for ultrasound examinations of the prostate. This
procedure may be used to acquire a tissue sample (biopsy) from areas of the
After your ultrasound images have been reviewed by a radiologist, your
personal physician will receive a report of the findings. Your physician then
will advise you of the results and discuss what further procedures, if any, are
There are no known side effects or after effects from ultrasound imaging, and
it is not necessary to take any special precautions following your examination.
The above patient information provided by the American Society of Radiologic
Technologist (ASRT) with permission. www.asrt.org