Ultrasound Exams Create Real-Time Images
Ultrasound is used to assess soft tissue structures such as muscles, blood vessels and organs. Nearly every organ in the body can be examined by ultrasound. Ultrasound uses high-frequency sound waves to create real-time images within the body. (Radiation is not used.) Ultrasound images show the structure and movement of the body’s internal organs as well as blood flow.
For an ultrasound test, gel is applied to the skin to help transmit the sound waves. A small, handheld instrument (a transducer) is passed back and forth over the area of the body being examined. The transducer sends high-pitched sound waves into the body. The sound waves reflect off body structures and are reflected back to the transducer. A computer analyzes the sound waves and converts them into a picture (sonogram) that is displayed on a monitor. Ultrasound may be used along with other forms of imaging, such as MRI.
Ultrasound Techniques for Different Conditions
There are different ultrasound techniques for different conditions. Some of the more common types of ultrasound exams include:
- Obstetrics — because ultrasound does not use radiation, it’s a very useful tool to use with pregnant women. An ultrasound scan provides a safe, non-invasive and accurate view of a fetus. In the Radiology Department, ultrasound is often used to quickly diagnose problems in pregnant women who come to the Emergency Department. The Maternal Fetal Care Center at Froedtert & the Medical College also uses ultrasound, including 3-D ultrasound and 4-D ultrasound, which allows viewing a moving fetus in real time.
- Gynecologic disorders — ultrasound is useful for diagnosing a variety of gynecologic disorders of the uterus, ovaries, Fallopian tubes and pelvis. It can detect tumors, cysts, fibroids and other disorders, often well before symptoms arise.
- Abdomen — initial evaluation of abdominal pain often begins with an ultrasound exam. Ultrasound is effective in investigating the gallbladder (e.g., for gall stones), obstructions of the bile ducts, and liver and kidney disease. It can detect the difference between a cyst and a tumor.
- Transplants — organ transplants involve many vein and artery connections. Doppler ultrasound is used to check blood flow in people who have received a transplant.
- Guidance for procedures — ultrasound is used to guide many procedures to diagnose and treat disease. For example, it can show the precise location to inject a drug into a joint, show where to inject Botox® to control significant drooling, locate abnormal growths to perform a biopsy, and guide the drainage of a pseudocyst (an abnormal, fluid-filled sac) in the pancreas. Ultrasound can also detect difficult-to-locate tumors to help in planning treatment. Ultrasound is also used for guiding many interventional radiology procedures.
- Musculoskeletal — ultrasound provides images of muscles, tendons, ligaments, joints and soft tissue throughout the body. It can detect problems such as a tear in the rotator cuff, the tendons that stabilize the shoulder joint, muscle tears and many other disorders.
- Emergency Department — ultrasound is used to diagnose a wide range of problems in the Emergency Department, from abdominal and pelvic pain to blockages in blood vessels.
- Surgery — ultrasound has many uses in surgery, such as finding tumors and locating stones in the kidneys, pancreas or bile ducts, and evaluating the spread of cancer.
Specialized Types of Ultrasound
- Doppler ultrasound uses a handheld device to view blood flow in arteries and veins throughout the body. It can show problems such as blocked or reduced blood flow in the major arteries of the neck that could cause a stroke, or blood clots in leg veins that could break loose and block blood flow to the lungs. For people who have received an organ transplant, Doppler ultrasound is used to check blood flow to the transplanted organ.
- Endoscopic ultrasound (EUS) involves the use of an endoscope, a thin, flexible tube that is passed through the mouth or anus to the area being examined. A small transducer in the endoscope produces sound waves to create images of the area. EUS is used to examine the lining and walls of the upper and lower gastrointestinal tract and nearby organs such as the pancreas, liver and gallbladder. It is also used to locate tissue for biopsy.