What Is a Doppler Ultrasound Used For?
In the medical field, the need for information is great. Doctors and nurses gather information on patients and diseases on a daily basis. They store the information and access it when needed to diagnose and treat patients with a variety of ailments. An ultrasound is one of the most effective, noninvasive diagnostic tools available to medical professionals. It is used to treat patients and diagnose illnesses from broken bones to cancer and heart disease. It’s truly a marvel of technology and a life-saving device. Before the invention of the ultrasound, the only way to view the internal structures of the body was with an incision and some pain for the patient. Doppler ultrasound is a continuation and advancement of the ultrasound technology that was developed from sonar. We will delve into the history behind the science and answer the question, “What is a doppler ultrasound used for?”
The History of the Doppler Effect
The basis for Doppler ultrasound is the doppler effect, which most of us are familiar with from watching the news and getting the weather forecast. The weatherman uses the doppler radar to show us the impending storms that are bearing down on the community. But what is the doppler effect? Surprisingly enough, we all know what it is and unknowingly encounter it often, as in several times a week or day, depending on where you live. In 1842 Austrian mathematician Christian Doppler developed the theory to explain the colors of binary stars. He said that the observed frequency of an electromagnetic wave or sound wave depends on the relative speed of the source and the observer. The change in the frequency is known as the Doppler effect or the Doppler shift. Any sound that is approaching you will sound higher than it really is, and if the sound is going away from you, it will sound lower than it actually is. Here’s what that means in a practical sense. If you are standing on a street corner and a police car is approaching with the lights on and the sirens blaring, the sound is far away. As the car approaches you the sound gets louder and louder. The sirens will be at their loudest and sound higher when the car is directly in front of you. As the car passes, the sirens get softer and sound lower as the car gets farther away from you. The pitch and intensity of the sirens never actually changes, but relative to where you are standing, they appear to. The reason that this happens is that as the car approaches, the distance that the sound waves must travel to reach your ears gets shorter and shorter. Each successive sound wave is emitted closer to you, making the sound louder and louder as it draws near. The opposite then happens as the car moves away; the waves must travel farther to reach your ears.
A Brief Lesson on Ultrasound
Ultrasound exams are ubiquitous today, and many people have had a least one in their lifetime. But ultrasound as a technology is less than a century old and didn’t become common until the 1960s. The first clinical use for it was in 1956, in Glasgow, Scotland. Dr. Ian McDonald and an engineer named Tom Brown were the first to develop ultrasound technology and use it to examine pregnant women. They made the first machine, and improvements have been made on the technology ever since. It is largely associated with OBGYN and monitoring the development of fetuses during pregnancy. Over the years, new uses for the technology have been implemented.
Discovering Doppler Ultrasound
The history of Doppler ultrasound in peripheral vascular diagnosis is measured in terms of basic developments. Many early developments occurred at Osaka University in Japan and the University of Washington in the United States. The first medical applications of Doppler sonography were in the late 1950s. Shigeo Satomura, a Japanese researcher, developed the first Doppler ultrasound device for medical diagnostic purposes. He was the first to report the construction of an ultrasonic flowmeter. A team in Seattle took that device and made significant strides to further the technology. A three-man team pioneered the creation of a duplex Doppler machine based on a mechanical sector-scanning head in which a single transducer crystal performed both imaging and Doppler functions withing the probe on a time-sharing basis.
Practical Uses for Doppler Ultrasound
In a broad sense, a doppler ultrasound can be used for all practical aspects of medicine to view any part of the human body. Doppler has come to be used in almost every medical discipline for the study of blood flow, tissue motion, and disease processes. Doppler ultrasound is predominantly used to safely study the circulation of the human body, including the reproductive system and the developing fetus. The study of the blood flow is important for monitoring heart health and studying heart disease. An echocardiogram can, within certain limits, produce an accurate assessment of the direction of blood flow and the velocity of blood and cardiac tissue at any point within the body using the Doppler effect. The Doppler effect is used, in this instance, to estimate how fast the blood flows by measuring the rate of change in its frequency. One of the limitations is that the ultrasound beam should be as parallel to the blood flow as possible. Velocity measurements allow assessment of cardiac valve areas and function, abnormal communications between the left and right side of the heart, leaking of blood through the valves, and calculation of the cardiac output. Contrast-enhanced ultrasound using gas-filled microbubble contrast media can be used to improve velocity or other flow-related medical measurements. Velocity measurements of blood flow are also used in other fields of medical ultrasonography, such as obstetric ultrasonography and neurology. Velocity measurement of blood flow in arteries and veins based on the Doppler effect is an effective tool for diagnosing vascular problems like stenosis. Additionally, a doppler ultrasound can be used to diagnose blood clots, poorly functioning valves in leg veins, and blocked arteries.
Conquest Imaging has a full lineup of high-quality ultrasound machines, including the Philips Epiq 7. Contact a member of the sales team today to meet your medical imaging needs.