What is an ultrasound examination (sonogram)?

Ultrasonography, sometimes called sonography, uses high-frequency sound waves and a computer to create images of blood vessels, tissues, and organs. Sonograms are used to view internal organs as they function, and to assess blood blow through various vessels. Ultrasound procedures are used to examine many parts of the body such as the abdomen, breasts, female pelvis, prostate, scrotum, thyroid and parathyroid, and the vascular system. During pregnancy, ultrasounds are performed to evaluate the development of the fetus.

How are ultrasounds performed?

Ultrasounds may be done on an outpatient basis, or as part of inpatient care. Although each hospital may have specific protocols in place, generally, an ultrasound procedure follows this process:

1. A gel-like substance is smeared on the skin in the area of the body being examined.
   
   
2. Using a hand-held transducer, a tool that sends ultrasound waves, the sound beam is sent through the patient's body.
   
   
3. The sound from the transducer is reflected off structures inside the body, and the information from the reflected sound is analyzed by a computer.
   
   
4. The computer creates a picture of the body structures on a television screen. The moving pictures can be recorded on film videotape.
   
   
5. There are no confirmed adverse biological effects on patients or instrument operators caused by exposures to ultrasound energy at the levels used for diagnostic purposes.

What are the different types of ultrasound?

Different ultrasound techniques exist for different conditions. Examples of some of the more common types of ultrasound examinations include the following:

• Doppler ultrasound - used to examine blood flow within veins and arteries and to detect blood clots.

• echocardiogram - used to see the heart and heart valves, and to evaluate the effectiveness of the heart's pumping ability.

• abdominal ultrasound - used to detect any abnormalities of the abdominal organs (i.e., kidneys, liver, pancreas, gallbladder), such as gallstones or tumors.

• renal ultrasound - used to examine the kidneys, urinary tract and to search for stones.

• obstetrical ultrasound - used to monitor the health of pregnancy and the growing fetus.

• pelvic ultrasound - used to find the cause of pelvic pain, such as an ectopic pregnancy, tumors or cysts.

• breast ultrasound - used to examine a mass or cyst in the breast tissue.

• thyroid ultrasound - used to see the thyroid and to detect any abnormalities.

• scrotal ultrasound - used to further investigate pain in the testicles, fluid in the scrotal sac, and testicular tumors.

• prostate ultrasound - used to examine any nodules felt during a physical examination and to guide prostatic biopsy.

• musculoskeletal ultrasound - used to examine joint or muscle pain for conditions, such as a torn ligament or tendon.

• Intraoperative ultrasound - used to help surgeons during operations or biopsy procedures.