Doppler ultrasound machines are probably the most popular type today, since it offers little or no risk and side effects. These involve technologically advanced mechanisms, specifically sending out sound waves to get clear images of virtually any part of the body. Those that are filled with air or covered with bone are an exception and are much harder to view. Understanding the approach and procedure will help you determine if it is the best for you.
Doppler ultrasound machines make use of the Doppler effect wherein reflected sound waves are used to evaluate blood as it moves through blood vessels. Doctors will know whether blood flow is normal along the major veins and arteries of the legs, arms and neck. Doctors will also find the presence of blockage or minimal blood flow through narrowed major arteries. For example, if blockage or narrowing is detected in the neck, the patient could be at risk for stroke. If blood clots are present in the veins of the legs, the patient could be at risk for deep vein thrombosis.
During the procedure, a transducer, which is a handheld instrument, will be passed lightly over the skin over the blood vessel. The transducer sends and gets amplified sound waves via a microphone. The sound waves will bounce off solid materials inside the body, including blood cells.
A change in pitch of the reflected sound waves or the Doppler effect will take place via the movement of blood cells. The pitch will not change if there is zero or insufficient blood flow. A computer processes the reflected sound waves to make pictures and graphs that will show blood flow through the vessels. The results will be saved for future comparison and evaluation.
4 Kinds of Doppler Ultrasound
There are 4 types of Doppler ultrasound – duplex Doppler, bedside Doppler, color Doppler and power Doppler. Duplex Doppler ultrasound machines use basic ultrasound approaches to create an image of the blood vessel, plus surrounding organs. The Doppler sounds will be transformed into a graph with the use of a computer. Bedside Doppler is also known as continuous wave Doppler. This kind involves the changes in sound wave pitches to get information about blood flow through blood vessels. Physicians will evaluate blood flow using the transducer to know if there is narrowing or blockage. This type is usually done in hospitals using a portable ultrasound machine.
Color Doppler makes use of basic ultrasound approaches to create an image of a blood vessel. The computer transforms the sounds received into colors that will entail the speed and direction of blood moving through the veins and arteries. Power Doppler is a new form which is about 5 times more sensitive compared to Color Doppler when examining blood flow.
This type can get images that are hard or impossible to get using standard types. It is very common when evaluating blood flow via vessels in solid organs. Traditionally, color and duplex dopplers were used in conjunction to know the speed and direction of blood flow accurately.
More Doppler Points
Doppler ultrasound machine results can be interfered by a number of factors such as the presence of bones over the area being examined or presence of gas in the intestines, presence of an open wound in the area to be examined, extreme obesity, irregular heart rhythms or heart disease which can alter blood flow patterns and a cold extremity which slows down blood flow.