What is ultrasound?
Ultrasound is like ordinary sound except it has a frequency (or pitch) higher than human beings can hear. When sent into the body from a transducer (scanner) resting on the patient's skin, the sound is reflected off internal structures. The returning echoes are received by the transducer and converted by an electronic instrument into an image of the internal structures on a viewing screen. Diagnostic ultrasound is commonly called sonography or ultrasonography.
Is ultrasound safe?
There are no known harmful effects associated with the medical use of sonography. Studies in humans have revealed no direct link between the use of diagnostic ultrasound and any adverse outcome. Although the possibility exists that biological effects may be identified in the future, current information indicates that the benefits to patients far outweigh the risks, if any.
What is Doppler?
Doppler ultrasound is a special form of ultrasound. With Doppler ultrasound, it is possible to see the structures inside the body and evaluate blood flow at the same time. One method of evaluation gives us information about the structures within the body and the other method tells us about blood flow.
Why should I have a Doppler ultrasound exam?
A Doppler ultrasound exam gives your physician a great deal of information about your blood vessels and about the way blood is passing through them. Doppler ultrasound is particularly well-suited to evaluating problems within the veins and arteries. Because we have blood vessels throughout the body, Doppler may be used almost anywhere. One of the most common uses of Doppler ultrasound, however, is in the neck to look at the carotid arteries. These vessels supply large amounts of blood to the brain and may become blocked.
In the heart, Doppler can tell us about the flow of blood and whether it is directed correctly. In the abdomen, Doppler can help evaluate blood flow to the liver and many other abdominal organs. Doppler also is used to evaluate blood flow in the legs and may be helpful in identifying blockages in the arteries and clots in the veins.
Who will perform the exam?
Doppler ultrasound may be performed by a vascular technologist, or a sonographer. The exam will be interpreted by a radiologist.
Will the exam hurt? Are there special preparations?
There is no pain involved in an ultrasound examination and for most Doppler exams, no preparation is necessary. Your doctor will ask you to refrain from eating and drinking in the morning of the exam, if the scan involves the upper abdomen.
What can I expect during the examination?
The pictures made by the returning echoes are displayed on one or more small TV screens which are studied by the specialist performing the scan. In addition, returning sound waves which have been reflected by moving blood can be heard by means of speakers in the instruments.
How long will it take?
The average Doppler ultrasound exam takes 30-60 minutes. The length of the exam is dependent upon a number of factors including the portion of the body to be examined. With hardening of the arteries, the vessels may be very difficult to evaluate and may require more scanning time.