Diagnostic Ultrasound

Diagnostic Ultrasound also called sonography or diagnostic medical sonography, is an imaging method that uses high-frequency sound waves to produce relatively precise images of structures within your body. The images produced during an ultrasound examination often provide valuable information for diagnosing and treating a variety of diseases and conditions.

Most ultrasound examinations are done using a sonar device outside of your body, though some ultrasound examinations involve placing a device inside your body.

Why it’s done

You may need to undergo an ultrasound for a variety of reasons. Ultrasound may be used, for example, to:

Assess a fetus
Diagnose gallbladder disease
Evaluate flow in blood vessels
Guide a needle for biopsy or tumor treatment
Evaluate a breast lump
Check your thyroid gland
Study your heart
Diagnose some forms of infection
Diagnose some forms of cancer
Reveal abnormalities in the genitalia and prostate
Evaluate abnormalities of the muscles and tendons

Risks

Diagnostic ultrasound is a safe procedure that uses low-power sound waves. There are no direct risks from a diagnostic ultrasound exam.

Although ultrasound is a valuable tool, it does have its limitations. Sound doesn’t travel well through air or bone, so ultrasound isn’t effective at imaging parts of your body that have gas in them or that are obscured by bone. Rather than using ultrasound to view these areas, your doctor may instead order other imaging tests, such as CT or MRI scans, or X-rays.

How you prepare

How you prepare for an ultrasound depends on which area of your body needs evaluation:

Most ultrasound exams require no preparation.
Some exams require that you forgo food and liquids for up to eight hours before the exam. This includes no chewing gum or tobacco use (smoking or chewing).
Other exams may require that you drink 32 oz. of water 1 hour prior to exam and not urinate before the exam to ensure that your bladder will be full, allowing better visualization of the uterus, ovaries or prostate.

When scheduling your ultrasound, ask us for specific instructions for your particular exam.

What you can expect

During an ultrasound exam, you usually lie on an examination table. A small amount of gel is applied to your skin. The gel helps eliminate the formation of air pockets between the ultrasound and your body. During the exam, a technician trained in ultrasound imaging (sonographer) presses a small hand-held device (transducer), about the size of a bar of soap, against your skin over the area of your body being examined, moving from one area to another as necessary. Based on the same principles as sonar, a technology used to detect underwater objects, the transducer generates and receives high-frequency sound waves that can’t be heard by the human ear.

As the sonographer places the transducer on your skin, crystals inside the transducer emit pulses of sound waves that travel into your body. Your tissues, bones and body fluids reflect the sound waves and bounce them back to the transducer. The transducer then sends this information to a computer, which composes detailed images based on the patterns created by the sound waves.

Ultrasound is usually a painless procedure. However, you may experience some mild discomfort as the sonographer guides the transducer over your body, especially if you’re required to have a full bladder. A typical ultrasound exam takes from 30 minutes to an hour.

Results

When your exam is complete, the sonographer and a radiologist generally view the ultrasound images on film or on a computer monitor. The radiologist analyzes the images and sends a report of the findings to your doctor usually within 48 hours.