Ultrasound imaging, also called ultrasound scanning or sonography, involves exposing part of the body to high-frequency sound waves to produce images inside of the body. Unlike X-Ray exams, ultrasound exams do not use ionizing radiation. Because ultrasound images are captured in real-time, they can show the structure and movement of the body's internal organs. By using a special ultrasound technique (Doppler), velocity of flow in a blood vessel can be evaluated. Ultrasound imaging is a noninvasive medical test that helps physicians diagnose and treat numerous medical conditions.
Areas of Application
- Abdomen - screening for non-specific symptoms such as pain
- Liver - tumors, cysts, or hepatitis (inflammation)
- Gall Bladder and Biliary Tract - stones and inflammation
- Pancreas - tumors, cysts, and pancreatitis (inflammation)
- Kidneys and urinary bladder - stones, tumors, and infection
- Aorta - aneurysm (abnormal size)
- Veins - blood clots
- Uterus - fibroids and endometrium (lining of the uterus) for bleeding
- Ovaries - tumors and cysts
- Prostate Gland - tumors, infection, and BPH (benign prostatic hypertrophy or enlargement with age)
- Scrotum - tumors and infection
- Thyroid Gland - benign and malignant nodules, thyroiditis (inflammation)
What Are The Benefits vs. Risks?
- Most ultrasound scanning is noninvasive and is usually painless.
- Ultrasound is easy-to-use and less expensive than other imaging methods.
- Ultrasound imaging uses no ionizing radiation. It causes no health problems and may be repeated as often as is necessary.
- For standard diagnostic ultrasound there are no known harmful effects on humans.
Learn More About Ultrasounds
About Ultrasound Examinations
How does the procedure work?
Ultrasound imaging is based on the same principles involved in the sonar used by bats, ships and fishermen. When a sound wave strikes an object, it bounces back, or echoes. By measuring these echo waves it is possible to determine how far away the object is and its size, shape, and consistency (whether the object is solid, filled with fluid, or both).
In an ultrasound examination, a transducer both sends the sound waves and records the echoing waves. When the transducer is pressed against the skin, it directs small pulses of inaudible, high-frequency sound waves into the body. As the sound waves bounce off of internal organs, fluids and tissues, the sensitive microphone in the transducer records tiny changes in the sound's pitch and direction. These signature waves are instantly measured and displayed by a computer, which in turn creates a real-time picture on the monitor. One or more frames of the moving pictures are typically captured as still images.
Doppler ultrasound, a special application of ultrasound, measures the direction and speed of blood cells as they move through vessels. The movement of blood cells causes a change in pitch of the reflected sound waves (called the Doppler effect). A computer collects and processes the sounds and creates graphs or color pictures that represent the flow of blood through the blood vessels.
How is the procedure performed?
For most ultrasound exams, the patient is positioned lying face-up on an examination table. A clear water-based gel is applied to the area of the body being studied to help the transducer make secure contact with the body and eliminate air pockets between the transducer and the skin. The sonographer (ultrasound technologist) then presses the transducer firmly against the skin and sweeps it over the area of interest. Doppler sonography is performed using the same transducer. For ultrasound of the female pelvis, a special transducer is comfortably placed into the vagina with the patient in a position similar to a routine gynecologal exam. For ultrasound of the prostate gland, a special transducer is comfortably placed into the rectum while the patient lies on his left side.
Have an upcoming ultrasound examination?
How do I prepare for my examination?
You should wear comfortable, loose-fitting clothing for your ultrasound exam. You may need to remove all clothing and jewelry in the area to be examined. You may be asked to wear a gown during the procedure. Other preparation depends on the type of examination you will have. For example, you will be asked not to eat or drink for as long as 12 hours before your exam to evaluate abdominal organs, so that swallowed air does not interfere with the sound waves. You may be asked to drink up to six glasses of water two hours prior to your exam and avoid urinating to evaluate the urinary bladder or pelvis.
Who will interpret the ultrasound?
A physician specifically trained to supervise and interpret radiology examinations will analyze the images and send a signed report to your primary care or referring physician, who will discuss the results with you.