Basic Principles of Ultrasound

Doppler ultrasound capabilities have increased enormously in the past few years. Technology is ever changing and the ultrasound is no different and it continues to grow in versatility as more demands are placed on the technology. Today the Doppler ultrasound is an important piece of equipment in dealing with heart disease. It's time you had understood the basic principles of ultrasound.

The Doppler ultrasound reflects sound waves which evaluate the blood as it flows through the vessels. This helps your doctor evaluate the blood flow through your major arteries and veins in the neck, legs, and arms. It can show reduce blood flow caused by narrowing in the arteries as well as blockages.

These narrowing in the arteries of the neck can lead to stroke while blood clots in the legs called deep vein thrombosis can break loose and block the flow of blood in the lungs.

A handheld transducer is passed lightly over the skin and blood vessels. Sound waves are sent which are then bounced off the solids which include the blood cells. The movement of the blood cells changes the pitch of the sound waves. This is called the Doppler Effect. When there is no blood flow there is not change in the sound pitch produced.

There are four types of Doppler ultrasounds used:

1. Power Doppler - uses the newest technology and its 5 times more sensitive at detecting blood flow than the color Doppler is and it is able to obtain images other Doppler equipment can't produce. It is generally used to evaluate the flow of blood through the vessels in organs.2. Bedside Doppler - uses the change in the pitch of the sound waves to produce the information on the flow of the blood through the vessels. The doctor listens to these sounds to evaluate whether there is a narrowed or blocked blood flow. This method is used in the hospital right at the patient's bed to quickly determine blood flow.3. Color Doppler - produces a picture of the blood vessel using the traditional ultrasound methods. The Doppler sounds are converted into color which is then overlain on the blood vessel image showing the speed and flow of the blood in the vessels.4. Duplex Doppler - also uses traditional ultrasound methods to produce pictures of both the organs and the blood vessels. The computer converts these Doppler sounds into graph form that shows the speed and direction of the flow of the blood in the vessels.

The Doppler is used to:1. Detect blood clots, narrowed blood vessels, and blocked vessels throughout the entire body but especially in the legs, arms, and neck. When arteries become narrowed or blocked they can cause dizziness, paralysis, vision loss, numbness, weakness, and other symptoms of stroke.2. Look for blood clots in the deep veins of the legs that can cause swelling and pain and if left untreated lead to pulmonary embolism.3. After a stroke or similar condition evaluate the flow of blood.4. Map veins that may be candidates for blood vessel grafts.5. Determine the amount of blood reaching a kidney transplant.6. Monitor blood flow following blood vessel surgery.7. Locate arterial plaque specifically in the carotid artery which can reduce blood flow to the brain and increase the risk of stroke.

Now that you understand the basic principles of ultrasound you can see why the Doppler ultrasound is such a powerful and important tool in the treatment and diagnosis of heart disease.

Yong has been working for a leading ultrasound manufacturer for last 8 years. At At www.ultrasoundlive.com he has provide information about different types of utlrassound equipments. Visit the website to get more information about ultrasound equipment and accessories.