Ultrasound imaging, also called ultrasound scanning or sonography, involves exposing part of the body to high-frequency sound waves to produce pictures of the inside of the body. Ultrasound exams do not use ionizing radiation (as used in x-rays).
Because ultrasound images are captured in real-time, they can show the structure and movement of the body's internal organs as well as blood flowing through blood vessels.
Ultrasound imaging is a noninvasive medical test that helps physicians diagnose and treat medical conditions.
Conventional ultrasound displays the images in thin, flat sections of the body. Advancements in ultrasound technology include three-dimensional (3-D) ultrasound that formats the sound wave data into 3-D images. Four-dimensional (4-D) ultrasound is 3-D ultrasound in motion.
Common Uses of Conventional Ultrasound
Ultrasound examinations can help diagnose a variety of conditions and assess organ damage following illness.
Ultrasound is used to help doctors evaluate symptoms such as:
Ultrasound is a useful way of examining many of the body's internal organs, including, but not limited to, the:
- Heart and blood vessels, including the abdominal aorta and its major branches
- Scrotum (testicles)
- Thyroid and parathyroid glands
- Uterus, ovaries, and unborn child (fetus) in pregnant patients
Ultrasound is also used to:
- Guide procedures such as needle biopsies, in which needles are used to extract sample cells from an abnormal area for laboratory testing.
- Diagnose a variety of heart conditions and to assess damage after a heart attack or diagnose for valvular heart disease.
A Doppler ultrasound study may be part of an ultrasound examination.
Doppler ultrasound is a special ultrasound technique that evaluates blood velocity as it flows through a blood vessel, including the body's major arteries and veins in the abdomen, arms, legs and neck.
Types of Doppler Ultrasound
- Color Doppler uses a computer to convert Doppler measurements into an array of colors to visualize the speed and direction of blood flow through a blood vessel.
- Power Doppler is a newer technique that is more sensitive than color Doppler and capable of providing greater detail of blood flow, especially when blood flow is little or minimal. Power Doppler, however, does not help the radiologist determine the direction of blood flow, which may be important in some situations.
- Spectral Doppler: Instead of displaying Doppler measurements visually, Spectral Doppler displays blood flow measurements graphically, in terms of the distance traveled per unit of time.
Doppler Ultrasound Uses
Doppler ultrasound helps your doctor see and evaluate:
- Blockages to blood flow (such as clots).
- Narrowing of vessels (which may be caused by plaque).
- Tumors and congenital malformation.
With knowledge about the speed and volume of blood flow gained from a Doppler ultrasound image, the physician can often determine whether a patient is a good candidate for a procedure like angioplasty.