Ultrasound is a noninvasive imaging test that shows structures inside
your body using high-intensity sound waves. Healthcare providers use
ultrasound exams for several purposes, including during pregnancy, for
diagnosing conditions and for image guidance during certain procedures.
What is an Ultrasound?
An ultrasound is an imaging test that uses sound waves to create
real-time pictures or video of soft tissues inside your body.
Ultrasound (also called sonography or ultrasonography) is a noninvasive
imaging test. An ultrasound picture is called a sonogram. Ultrasound
uses high-frequency sound waves to create real-time pictures or video of
internal organs or other soft tissues, such as blood vessels.
Ultrasound enables healthcare providers to “see” details of soft tissues
inside your body without making any incisions (cuts). And unlike X-rays,
ultrasound doesn’t use radiation.
Many people who hear the term "ultrasound" likely picture a
pregnant woman in their doctor's office getting a sneak peek
of the baby growing inside her womb — perhaps even a gender
reveal. But while fetal imaging is one of the most common
uses of ultrasounds, this diagnostic tool actually has many
applications.
Ultrasound vs. X-ray
Ultrasound and X-ray are both imaging tests. X-rays create pictures of
the inside of your body using a small amount of radiation. Most of us
are familiar with X-ray imaging of our bones or teeth, but X-ray images
can diagnose a range of conditions and injuries. They are used to
examine bones and soft tissue. An ultrasound uses high-frequency sound
waves to create these images.
Ultrasound vs. sonogram
Ultrasound is the test used for imaging. Sonogram is the image an
ultrasound produces.
How does an ultrasound work?
During an ultrasound, a healthcare provider passes a device called a
transducer or probe over an area of your body or inside a body opening.
The provider applies a thin layer of gel to your skin so that the
ultrasound waves are transmitted from the transducer through the gel and
into your body.
The probe converts electrical current into high-frequency sound waves
and sends the waves into your body’s tissue. You can’t hear the sound
waves.
Sound waves bounce off structures inside your body and back to the
probe, which converts the waves into electrical signals. A computer then
converts the pattern of electrical signals into real-time images or
videos, which are displayed on a computer screen nearby.
What are the different kinds of ultrasounds?
There are three main categories of ultrasound imaging, including:
Pregnancy ultrasound (prenatal ultrasound).
Diagnostic ultrasound.
Ultrasound guidance for procedures.
Pregnancy ultrasound
Healthcare providers often use ultrasound (often called prenatal or
obstetric ultrasound) to monitor you and the fetus during pregnancy.
Providers use prenatal ultrasound to:
Confirm that you’re pregnant.
Check to see if you’re pregnant with more than one fetus.
Estimate how long you’ve been pregnant and the gestational age of
the fetus.
Check the
fetal growth and position.
Determine the fetus's biological sex
See the fetal movement and
heart rate.
Check for congenital conditions (birth
defects) in the fetal brain, spinal cord,
heart or other parts of its body.
Check the amount of amniotic fluid.
Most healthcare providers recommend an ultrasound at 20 weeks pregnant.
This test tracks the fetus’s growth and development during pregnancy.
This ultrasound may also show the biological sex of the fetus. Tell your
technician if you do or do not want to know the sex.
Your provider may order extra scans to get answers to any questions or
concerns, such as the potential for congenital conditions.
Diagnostic ultrasound
Providers use diagnostic ultrasounds to view internal parts of your body
to see if something is wrong or not working properly. They can help your
provider learn more about what’s causing a wide range of symptoms, such
as unexplained pain, masses (lumps) or what may be causing an abnormal
blood test.
For most diagnostic ultrasound exams, the technician places the
transducer (probe) on your skin. In some cases, they may need to place
the probe inside your body, such as in your vagina or rectum.
The type of diagnostic ultrasound you have depends on the details of
your case.
Examples of diagnostic ultrasounds include:
Abdominal ultrasound: An ultrasound probe moves
across the skin of your midsection (belly) area. Abdominal
ultrasound can diagnose many causes of abdominal pain.
Kidney (renal) ultrasound: Providers use kidney
ultrasound to assess the size, location and shape of your
kidneys and related structures, such as your ureters and
bladder. Ultrasound can detect cysts, tumors, obstructions or
infections within or around your kidneys.
Breast ultrasound: A breast ultrasound is a
noninvasive test to identify
breast lumps and
cysts. Your provider may recommend an ultrasound after an
abnormal
mammogram.
Transesophageal echocardiogram, which probes the
esophagus so that the sonographer can obtain clearer
images of the heart.
Doppler ultrasound: This is a special ultrasound
technique that assesses the movement of materials, like blood, in
your body. It allows your provider to see and evaluate blood flow
through arteries and veins in your body. Doppler ultrasound is often
used as part of a diagnostic ultrasound study or as part of a
vascular ultrasound.
Pelvic ultrasound: A pelvic ultrasound looks at
the organs in your pelvic area between your lower abdomen (belly)
and legs. Some of the pelvic organs include your bladder, prostate,
rectum, ovaries, uterus and vagina.
Transvaginal ultrasound: Your provider inserts
a probe into your vaginal canal. It shows reproductive tissues such
as your uterus or ovaries. A transvaginal ultrasound is sometimes
called a pelvic ultrasound because it evaluates structures inside
your pelvis (hip bones).
Thyroid ultrasound: Providers use ultrasound to
assess your thyroid, a butterfly-shaped
endocrine gland in your neck. Providers can measure the size of
your thyroid and see if there are
nodules or lesions within the gland.
Transrectal ultrasound: Your provider inserts an
ultrasound probe transducer into your rectum. It evaluates your
rectum or other nearby tissues, such as the prostate in
males.
Ultrasound guidance for procedures
Providers sometimes use ultrasound to perform certain procedures
precisely.
A common use of ultrasound is to guide needle placement to
sample fluid or tissue from:
Tendons.
Joints.
Muscles.
Cysts or fluid collections.
Soft-tissue masses.
Organs (liver, kidney or prostate).
Transplant organs (liver, kidney or pancreas).
Examples of other procedures that may require ultrasound guidance
include:
Embryo transfer for in vitro fertilization.
Nerve blocks.
Confirming the placement of an IUD (intrauterine device) after
insertion.
Lesion localization procedures.
Therapeutic ultrasound
A low-frequency ultrasound has been used to treat various
conditions since the 1950s. Among the FDA-approved uses of a
therapeutic ultrasound are:
Cancer
Uterine fibroids
Glaucoma
Kidney stones
Plantar fasciitis
Liposuction
Bone fractures
There can be some significant side effects of using an
ultrasound for treatment, so your health care professional
will carefully weigh the benefits and drawbacks before using
this manner of treatment.
Other uses of an ultrasound
Additionally, ultrasound technology has advanced to allow
for other types of imaging:
Doppler is a special type of ultrasound that creates
images of blood flow through vessels.
Bone sonography helps doctors diagnose osteoporosis.
Echocardiograms are used to view the heart.
Three-dimensional imaging adds another dimension to
the ultrasound image, creating three-dimensional
interpretations rather than the flat two-dimensional
images that are made with the traditional ultrasound.
Four-dimensional ultrasounds show three-dimensional
images in motion.
2D vs 3D vs 4D ultrasound?
For ultrasounds during pregnancy, the traditional ultrasound is a
two-dimensional (2D) image of the fetus. 2D ultrasound produces outlines
and flat-looking images, which allows your healthcare provider to see
the fetus's internal organs and structures.
Three-dimensional (3D) ultrasound allows the visualization of some
facial features of the fetus and possibly other body parts such as
fingers and toes. Four-dimensional (4D) ultrasound is 3D ultrasound in
motion. Providers rarely use 3D or 4D fetal ultrasound imaging for
medical purposes, though it can be useful in diagnosing a facial or
skeletal issue. They do, however, use 3D ultrasound for other medical
purposes, such as evaluating uterine polyps and fibroids.
While ultrasound is generally considered to be safe with very low risks,
the risks may increase with unnecessary prolonged exposure to ultrasound
energy or when untrained users operate an ultrasound machine. Because of
this, the U.S. Food and Drug Administration (FDA) advises against
getting a 3D ultrasound for non-medical reasons such as for “keepsake”
moments or entertainment.
Benefits of an Ultrasound
Ultrasounds offer many advantages:
They are generally painless and do not require needles,
injections, or incisions.
Patients aren't exposed to ionizing
radiation, making the procedure safer than diagnostic techniques
such as X-rays and CT scans. In fact, there are no known harmful
effects when used as directed by your health care professional.
Ultrasounds capture images of soft tissues that don't show up
well on X-rays.
Ultrasounds are widely accessible and less expensive than other
methods.
Who performs an ultrasound?
A doctor or a healthcare provider called an ultrasound technician or
sonographer performs ultrasounds. They’re specially trained to operate
an ultrasound machine properly and safely.
It’s important to always have your ultrasound performed by a medical
professional and in a medical facility.
How do I prepare for an ultrasound?
The preparations will depend on the type of ultrasound you’re having.
Some types of ultrasounds require no preparation at all.
For ultrasounds of the pelvis, including ultrasounds during pregnancy,
of the
female reproductive system and of the
urinary system, you may need to fill up your bladder by drinking
water before the test.
For ultrasounds of the abdomen, you may need to adjust your diet or fast
(not eat or drink anything except water) for several hours before your
test.
In any case, your healthcare provider will let you know if you need to
do anything special to prepare for your ultrasound. They may give you
instructions during an appointment or when scheduling your ultrasound.
Instructions may also be available in your electronic medical records if
you use such a system.
What happens during an ultrasound?
Preparation for an ultrasound varies depending on what body part you’ll
have scanned. Your provider may ask you to remove certain pieces of
clothes or change into a hospital gown.
Ultrasounds that involve applying the transducer (probe) over your skin
(not in your body), follow these general steps:
You’ll lie on your side or back on a comfortable table.
The ultrasound technician will apply a small amount of water-soluble
gel on your skin over the area to be examined. This gel doesn’t harm
your skin or stain your clothes.
The technician will move a handheld transducer or probe over the gel
to get images inside your body.
The technician may ask you to be very still or to hold your breath
for a few seconds to create clearer pictures.
Once the technician has gotten enough images, they’ll wipe off any
remaining gel on your skin and you’ll be done.
An ultrasound test usually takes 30 minutes to an hour. If you have any
questions about your specific type of ultrasound, ask your healthcare
provider.
Is an ultrasound painful?
Ultrasounds that are performed externally (over your skin) are generally
not painful. You won’t feel the sound waves that ultrasound uses. If you
have to have a full bladder for the procedure, it may be uncomfortable.
It may also be uncomfortable to lay on the exam table if you’re
pregnant.
Ultrasounds that go inside body cavities, such as your vagina or rectum,
may be uncomfortable, but they shouldn’t hurt.
Are ultrasounds safe?
Yes, research to date has largely shown ultrasound technology to be safe
with no harmful side effects. Ultrasound doesn’t use radiation, unlike
some other medical imaging tests, such as X-rays and
CT scans.
Still, all ultrasounds should be done by a professional who has training
in using this specialized technology safely.
Results
When should I know the results of my ultrasound?
The time it takes to get your results depends on the type of ultrasound
you get. In some cases, such as prenatal ultrasound, your provider may
analyze the images and provide results during the test.
In other cases, a radiologist, a healthcare provider trained to
supervise and interpret radiology exams, will analyze the images and
then send the report to the provider who requested the exam. Your
provider will then share the results with you or they may be available
in your electronic medical record (if you have an account set up) before
your provider reviews the results.
What conditions can be detected by ultrasound?
Ultrasound can help providers diagnose a wide range of medical issues,
including:
Abnormal growths, such as
tumors or
cancer.
Blood clots.
Enlarged spleen.
Ectopic pregnancy (when a fertilized egg implants outside of
your uterus).
What questions should I ask my healthcare provider?
If you need an ultrasound, you may want to ask your provider the
following questions:
What type of ultrasound do I need?
What should I do to prepare for my ultrasound?
Do I need any other tests?
When should I expect to get test results?
How Much Does an Ultrasound Cost?
The cost of your ultrasound depends on where you live and
the type of scan you get. Generally, a pregnancy ultrasound
can cost as little as $200 up to $1,000 or more. Most
insurance companies cover the cost of prenatal ultrasounds,
and you should check with your insurer for out-of-pocket
costs for other types of ultrasounds.
One Final Note..
An ultrasound is a test that takes images inside your body.
The test uses high-frequency sound waves to create pictures
in real time of organs and soft tissue. Not just a tool
during pregnancy, an ultrasound can be used to examine your
kidneys, breasts, vascular system, thyroid gland, and pelvic
organs.
Ultrasounds are common, safe and effective imaging tests. Make sure you
get an ultrasound from a well-trained professional (sonographer) who
understands how to use this technology properly. If you have any
questions about your specific ultrasound test, talk to your healthcare
provider. They’re available to help.