Most of us are familiar with at least one use of ultrasound – those black and white first “pictures” of a baby. Ultrasound, which uses high frequency sound waves to produce images, has many more medical applications.
Ultrasound is similar to the sonar that ships and submarines use to show what’s in the water around them. With medical ultrasound, a wand-like instrument called a transducer sends out waves of high frequency sound. As these sound waves pass through the body, certain structures like organs, tissues and tumors reflect the wave back. That reflection or echo is then used to create a picture of what’s ahead.
Medical Uses of Ultrasound
In addition to taking those early pictures of a developing baby, ultrasound has many uses including helping doctors determine the causes of pain, swelling and infection. Doctors also can use ultrasound to view organs including:
- Heart and blood vessels including the flow of blood and potential narrowing of vessels
- Uterus and ovaries
- Thyroid and parathyroid glands
Ultrasound can help doctors with a number of medical procedures such as a biopsy of a suspicious mass. A breast ultrasound may be one of the tools used to check areas found during a screening mammogram.
Advances in Ultrasound
Today there are many types of ultrasound used in the medical field.
- Color Doppler helps doctors see the speed and direction of blood flow through a vessel.
- Power Doppler has more sensitivity than a color Doppler and provides even more detailed pictures of the blood flow but doesn’t indicate the direction of the flow.
- Spectral Doppler develops graphs that show the distance blood flows over a period of time.
- 3-D and 4-D Ultrasound Imaging give doctors nearly real-time views of the body thanks to computer advances.
These new ultrasounds not only show detailed pictures of babies in the womb, but also provide faster and more accurate views of the body and on a wider array of patients.
Preparing for an Ultrasound
The preparation you’ll need for an ultrasound exam depends on the type of exam you’ll be having. In general, you should wear loose, comfortable clothing that is easy to remove. You may need to undress and wear a patient gown for the exam. Please leave any jewelry and valuables at home.
Please ask your doctor for specific instructions about whether you should eat or drink before the exam. For some exams, you will need to have a full bladder so that we can get a better look at your abdominal organs. For others, you may need to refrain from eating and drinking for up to 12 hours before the exam.
What’s an Ultrasound exam like?
Ultrasound exams are generally painless and don’t take a lot of time. If you are having a standard, diagnostic ultrasound, there are no known harmful effects.
You’ll lie down on a table next to the ultrasound machine. The technologist will rub some gel on your skin around the area to be examined. Then he or she will press the transducer firmly against your body and begin moving it back and forth to produce the images needed.
You may feel some minor discomfort from the pressure of the transducer.
Some ultrasounds require a probe into your body in order to get a better view. A transesophageal echocardiogram is a type of ultrasound where the transducer is inserted into the esophagus in order to view the heart. Men with prostate problems may need a transrectal ultrasound that inserts a transducer into the rectum in order to view the prostate. A transvaginal ultrasound uses a transducer that is placed into a woman’s vagina in order to look at the uterus and ovaries.
Most ultrasound exams take between 30 minutes and one hour, and you usually can return to your normal activities after the exam.