Covers imaging test to check the thyroid gland and parathyroid glands. Includes info on problems test checks for, such as lumps in the thyroid gland or enlarged thyroid and parathyroid glands. Covers how it is done. Discusses possible results.
The thyroid gland makes a
hormone called thyroxine that controls how fast the body converts food into
energy (metabolism). Parathyroid hormone (PTH) is made by the
parathyroid glands and controls the amount of calcium and phosphorus in the
During a thyroid and parathyroid ultrasound, a small
handheld instrument called a transducer is passed back and forth over the neck
to form a picture of the thyroid gland and parathyroid glands.
Why It Is Done
A thyroid and parathyroid ultrasound is
Check lumps (thyroid nodule) in the
thyroid gland. A thyroid ultrasound can usually show the difference between a
solid thyroid gland nodule and a simple fluid-filled sac (cyst).
Find out whether the thyroid gland is enlarged. A
thyroid ultrasound may also be used to keep track of the size of the thyroid
gland during treatment for a thyroid problem.
Look for enlarged
parathyroid glands caused by disease. Normal parathyroid glands are often
difficult to see on ultrasound and cannot be felt during physical examination.
But abnormal parathyroid glands may be enlarged and easily seen by
Guide the placement of the needle during a thyroid
How To Prepare
No special preparation is required
before having this test. You will need to remove jewelry from your head or neck
before the test.
Talk to your doctor about any
concerns you have regarding the need for the test, its risks, how it will be
done, or what the results may mean. To help you understand the importance of
this test, fill out the
medical test information form(What is a PDF document?).
How It Is Done
A thyroid and parathyroid ultrasound is
usually done by a
radiologist or by an ultrasound technologist. It is
done in an ultrasound room in a doctor's office or hospital.
may be asked to undress above the waist and drape a paper or cloth covering
around your shoulders. Remove all jewelry from your head or around your
You will lie on your back on a high table with your neck
stretched out and a pillow under your shoulders. Gel will be spread on your
neck to improve the passage of the sound waves (they do not pass easily through
air). Sometimes a small water-filled bag or gelatin sponge is placed over your
throat to help conduct the sound waves. The transducer will be pressed against
your neck (or against the water-filled bag or gelatin sponge, if used), then
moved back and forth over your neck. A picture of your thyroid gland and the
tissue around it can be seen on a video monitor. You may be asked to turn your
head away from the side being scanned so the jawbone is out of the way.
The test takes about 30 minutes. You may be asked to wait until the
radiologist has reviewed the information. The radiologist may want to do
additional ultrasound views of your neck.
How It Feels
The gel may feel cold when it is applied
to your neck. Keeping your neck extended during the test may be uncomfortable,
but you should not feel discomfort from the transducer or sound waves. You will
be able to breathe and swallow normally during the test, and you will not hear
the sound waves.
There is very little chance of a problem from a
thyroid or parathyroid ultrasound test.
A thyroid ultrasound
test does not use radiation, so it is safe to use during pregnancy and will not
harm your growing baby.
The thyroid gland and parathyroid glands are
the right shape and are in the right place.
The glands are not too big or too
No growths or other abnormalities are
The thyroid gland is too big (goiter) or a growth (thyroid nodule) or
cyst is seen in the thyroid gland.
The parathyroid glands are too
What Affects the Test
Reasons you may not be able to
have the test or why the results may not be helpful include:
Not being able to hold still during the
procedure. Movement can interfere with the quality of the ultrasound
Having an open wound in the area that needs to be
What To Think About
A radioactive thyroid scan and radioactive
iodine uptake (RAIU) test are nuclear medicine tests that use a radioactive
substance to see how well the thyroid is working and identify thyroid problems.
For more information, see the topic
A thyroid ultrasound does
not use a radioactive substance; it is easier to perform and is less expensive
than a radioactive thyroid scan or RAIU test. But a thyroid ultrasound does not
provide information about how well the thyroid gland is working.
A thyroid ultrasound may be done at the same time as an RAIU
test. RAIU testing is used more often than a thyroid ultrasound to identify
problems such as
hyperthyroidism. A thyroid ultrasound can be used to
identify different types of thyroid problems, especially problems such as
Thyroid nodules are common, especially in women and older
Thyroid ultrasound can usually show the difference between
a cyst, a solid nodule, or another type of mass that needs further testing. A
fluid-filled sac that is smooth and round and that does not have any particles
floating in it is likely to be a simple cyst. A lump that does not have any
fluid or that has fluid with floating particles needs to be checked more
closely. If a solid nodule is found, a thyroid
biopsy may be needed.
Other Works Consulted
Pagana KD, Pagana TJ (2010). Mosby’s Manual of Diagnostic and Laboratory Tests, 4th ed. St. Louis: Mosby.
How this information was developed to help you make better health decisions.