The patient should wear comfortable, loose-fitting clothing for the ultrasound exam. Your doctor may instruct the patient not to eat or drink for as many as 12 hours before your appointment. Clothing and jewellery in the area to be examined will have to be removed.
The equipment consists of a transducer and a monitoring system. The transducer is a small, hand-held device that resembles a microphone. The Radiologist or Sonographer spreads a lubricating gel on the area being examined and then presses this device gently but firmly against the skin.
The ultrasound image is immediately visible on a nearby screen that looks much like a computer or television monitor. The radiologist or Sonographer watches this screen during an examination and captures representative images for storage. Often the patient is able to see it as well.
The ultrasound transducer generates sound waves that pass through the skin and also serves as a microphone to record the returning sounds—the echoes. When pressed against the skin, the transducer directs high-frequency sound waves toward the structures being studied and records any changes in the pitch and direction of the returning echoes. The bounce-back echoes, or the signature, are automatically measured by the computer and converted electronically to a picture that shows what is happening at that instant—creating a so-called “real-time” image on the monitor screen. These images can be videotaped, or they may be frozen in time to obtain still pictures. If a Doppler study is done, blood flow can be displayed in color on the screen and actually heard.
The patient is positioned on an examination table that can tilt and move. A clear gel is applied to the area that will be examined. The gel helps the transducer make a secure contact and eliminates air pockets between the transducer and the skin, since the sound waves cannot penetrate air. The Sonographer then presses the transducer firmly against the skin and sweeps it back and forth to image the area of interest, reviewing the images on the monitor and capturing “snapshots” as required. The entire area of interest will be scanned, obtaining images from different perspectives. Sometimes the examiner may want to obtain images while you are sitting or standing upright. The examination usually takes less than 45 minutes.
When the examination is complete, the patient may be asked to dress and wait while the ultrasound images are reviewed, either on film or on a monitor. Often, though, the Sonographer or Radiologist is able to review the ultrasound images in real time as they are acquired, and the patient can be released immediately.
A radiologist, who is a physician experienced in ultrasound and other radiology examinations, will analyze the images and send a signed report with his or her interpretation to the patient’s personal physician. The patient receives ultrasound results from the referring physician who ordered the test results. New technology also allows for distribution of diagnostic reports and referral images over the Internet at some facilities.