What Is an Ultrasound?

Types of Ultrasound

Most ultrasounds are done using a transducer on the surface of the skin. Sometimes, however, doctors and technicians can get a better diagnostic image by inserting a special transducer into one of the body's natural openings:

• In a transvaginal ultrasound, a transducer wand is placed in a woman’s vagina to get images of her uterus and ovaries.
• A transrectal ultrasound is sometimes used in the diagnosis of prostate conditions.
• A transesophageal echocardiogram uses the transducer probe in the esophagus so that the sonographer can obtain clearer images of the heart.

Additionally, ultrasound technology has advanced to allow for different 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.
• 3D imaging adds another dimension to the ultrasound image, creating three-dimensional interpretations rather than the flat two-dimensional images that are made with traditional ultrasound.
• 4D ultrasounds show 3D images in motion.

Benefits of 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.
• Ultrasound captures images of soft tissues that don't show up well on X-rays.
• Ultrasounds are widely accessible and less expensive than other methods.

What to Expect During an Ultrasound

Depending on the type of ultrasound test you are having, your doctor may offer special instructions, such as not eating or drinking anything for a number of hours before the test. Or you may be advised to drink several glasses of water in the time leading up to the test and refrain from using the bathroom to ensure that your bladder is full.

You should wear comfortable clothing that is easy to remove or partially remove. In some cases, you may need to disrobe or wear a gown, but often an ultrasound technician can easily access the area of the body that is being screened without your having to take off your clothes.

The technician will apply a water-based gel to the area. This is so the transducer can easily glide across your skin without any air in between. He or she may be looking for specific markers and may make measurements or notes while the test is in progress.

A typical ultrasound takes between 30 minutes and an hour. Ultrasounds usually are not uncomfortable, and you are awake and alert during the procedure. Often a technician will discuss what he or she is seeing during the test, but in some instances, you may need to wait to discuss the findings with your doctor.