Doctors use a number of different imaging procedures to look at the structures within our feet and ankles. One of the most commonly used of these procedures is foot and ankle ultrasound (also known as a sonogram), which uses high-frequency sound waves to form an image of the bones and other parts of the foot and ankle. This technique has been around for over fifty years, and it is useful for diagnosing a variety of injuries and diseases.
How Does Foot and Ankle Ultrasound Work?
The term ultrasound refers to sounds whose frequencies are so high that they are out of the range of human hearing. In all other respects, ultrasound waves are no different from ordinary sound.
Ultrasound works by focusing these high-frequency sound waves on the area the doctor wishes to examine. The sound waves bounce off the bones and soft tissues and are picked up by the same device that emitted them; this device is called a transducer. The transducer sends this information to a computer, which uses it to form an image.
Why Are Foot and Ankle Ultrasound Examinations Done?
Although it can be used to diagnose fractures and other conditions related to bones, ultrasound is more commonly used to look at problems with soft tissue.. Foot and ankle ultrasound examination can be useful for diagnosing and treating the following conditions, among others (click on links for more information):
- Morton’s Neuroma
- Heel spurs
- Tarsal tunnel syndrome
- Ankle injuries involving ligaments or tendons
- Plantar fasciitis
How Does Ultrasound Differ from MRI or X-Ray?
Ultrasound is considerably less expensive than other imaging techniques such as x-ray, MRI, or CT scanning, and it takes less time than many of these kinds of tests. This is especially true of ultrasound compared to MRI, which can take up to half an hour and is problematic for patients who are claustrophobic. The equipment necessary to conduct ultrasound examinations also takes up much less space than MRI or CT scan equipment, or even an x-ray machine.
Another advantage of ultrasound is that it does not use ionizing radiation, unlike x-rays or CT scans. This makes ultrasound safer than other imaging methods (not that x-rays, MRIs, or CT scans are dangerous, mind you).
What to Expect During a Foot or Ankle Ultrasound Examination
No changes to your normal routine will be necessary prior to your foot or ankle ultrasound examination; you can eat whatever you would normally eat. After you arrive at the doctor’s office and enter the examination room, you will lie down on a table. The doctor (or a technician or nurse) will apply a clear gel to your skin, covering the entire area surrounding the part of your foot or ankle that is being examined. This gel helps to conduct the sound waves.
Your doctor will begin with a handheld device—the transducer—which he or she will move slowly and carefully over and around the affected area. Depending on what part of your foot or ankle is being examined, you may be asked to move to a different position so that images can be taken from a different angle.
The procedure is entirely painless. In fact, you are unlikely to feel anything at all, although the gel is cold and wet, which some people may find uncomfortable.
Risks of Foot or Ankle Ultrasound
Because ultrasound examinations do not rely on radiation, there is absolutely no known risk of injury or any other complication.
Other Uses for Foot and Ankle Ultrasound
Ultrasound can also be used to guide injections so that they can be delivered to the precise location where they are needed, although some doctors question whether this is a sufficient improvement over traditional methods to justify the expense.
Ultrasound waves are also used for a procedure known as EPAT, which is done in order to break up scar tissue that may have formed inside the body following an injury or surgery. (To learn more about foot and ankle EPAT, click here.)
Talking to Your Doctor
Here are some questions you may want to ask your doctor before your foot or ankle ultrasound examination:
- How long will it take?
- Is this test expensive? Will my insurance cover it?
- What do you expect this procedure to tell us about my injury or condition?