Sonography is a diagnostic medical test that uses high-frequency sound waves. Also called ultrasound waves that bounce off of structures in the body and create an image. The test is often referred to simply as ultrasound or as a sonogram.
Sonography uses a device called a transducer to send out ultrasound waves and listen for the echo. A computer translates the ultrasound waves into an image. A trained technician can see, measure, and identify structures in the image. A specially trained healthcare provider then reads the images to help diagnose medical conditions.
A sonogram image can show the sizes and shapes of structures, good and bad, inside the body. The harder and denser the tissue, the more it bounces sound waves back to the transducer and the brighter the resulting image becomes.
Sonography is useful for evaluating the size, shape, and density of tissues. This helps diagnose certain medical conditions. Traditionally, ultrasound imaging is great for looking into the abdomen without having to cut it open.
Abdominal ultrasound, in particular, is often used to diagnose;
gallbladder disease or gallstones
kidney stones or kidney disease
uterine growths or fibroid
and other conditions
A sonogram is most commonly used is to monitor the development of the uterus and fetus during pregnancy. It can also be used to evaluate glands, breast lumps, joint conditions, bone disease, testicular lumps, or to guide needles during biopsies.
Sonography can also recognize blood or fluid flow. The computer can especially recognize fluid that is flowing toward or away from the transducer. It uses color overlays on the image to show the direction of flow. Very hard and dense tissues or empty spaces, such as organs filled with gas, do not conduct ultrasound waves and therefore cannot be viewed on a sonogram.
Sonography is often used before moving to image technologies that have more potential for complications.
Computerized tomography (CT) scanning exposes you to significant levels of radiation.
Magnetic resonance imaging (MRI) uses an extremely strong magnet to capture the image. The strength of an MRI magnet can limit its use in patients with metal in their bodies (braces, for example).
Risks and Contraindications
A sonogram is a noninvasive imaging test and has no known complications. Ultrasound waves are thought to be harmless and the test is usually performed externally on the surface of the skin. Sonography has no known risks or complications when used externally on the surface of the skin.2
While the energy of the ultrasound waves could potentially irritate or disrupt tissues with prolonged exposure, the computer modulates the power of the sound and a trained technician uses techniques to minimize exposure times and angles. So, sonography is the safest of the imaging tests.
Before the Test
Healthcare providers order sonography often as a first-line test, usually together with blood tests. We will often ask you to fast (not eat or drink) for six hours before an abdominal ultrasound to look at the gallbladder. Or tell you to drink several glasses of water and not urinate before a sonogram of the bladder.
A sonogram usually doesn’t normally take longer than 30 minutes.
Once the technician acquires all of the pictures, he or she will check to make sure no other views are required.
Most of the time, the technician will not give you any results straight away. Once we interpret the images from the sonogram, the report will be made available to you and your healthcare provider.
What to Wear
You should wear something easy to remove. In most cases, you will only have to expose the skin that the technician is going to need access to. An abdominal ultrasound, for example, can be done wearing pants and a shirt. You will just have to pull the shirt up to expose the abdomen.
In the case of a transvaginal sonogram, you will have to undress below the waist, including removing the underwear.
Food and Drink
As noted above, the reason for the sonography will determine whether you need to fast, drink fluids, or neither.
Cost and Health Insurance
Sonography is a relatively inexpensive imaging test. It is covered by most insurances and might require pre-authorisation depending on the reason the healthcare provider ordered the sonogram.
During the Test
Here’s what you can expect before, during, and after a sonogram.
Plan to arrive slightly earlier than your appointment so that you can check-in and fill out any necessary paperwork. If you were asked to follow specific food and drink instructions, you will be asked to confirm that you did.
Throughout the Test
A sonogram is conducted by a single technician. The entire sonogram will likely take less than 30 minutes.
The technician will ask you to undress enough to expose the area where the test will be performed and to lie down on the bed.
The technician will coat the transducer with conductive gel, which feels like lubricant jelly. If possible, depending on the tools and supplies available, the gel will be warm. Then the technician will slide the transducer over the skin, sometimes with firm pressure. Occasionally the pressure could cause some mild discomfort.
Using the transducer to point to areas of interest, the technician will use the computer to capture images and might use a mouse to drag lines across the screen. The lines help measure size, like a virtual yardstick.
When the sonogram is over, the technician will usually provide a towel to wipe off the conductive gel. Once the technician confirms that all the necessary images have been captured, you will be free to get dressed. There are no special instructions or side effects to manage.
Interpreting the Results
It only takes a few minutes to interpret most sonography results. The results will describe what is on the images and what those findings might suggest. This can mean various things depending on the area of the body tested.