What Is Ultrasound?

Ultrasound describes sound frequencies beyond (ultra-) the range of normal human hearing

1. What is the range of sound frequencies audible to humans?

20 hertz to 20,000 hertz

1. Diagnostic ultrasound uses frequencies between:

1 megahertz to 18-20 megahertz 

1. Convert 20 kHz to hertz

20 kHz x 1000_ = 20,000 Hertz

                                  1 

 Ultrasound Applications

• automatic door openers and to detect flaws in metals

• Common use of ultrasound is sonar, which can locate objects under water as well as determine the distance.

• Has medical uses in both diagnostic and therapeutic applications

• Used in physical and occupational therapy to increase blood flow to help speed up the healing process and to create a warming in the tissues.

• Lithotripsy: ultrasound is used at high power levels to break up gallstones, kidney stones, and even heel spurs.

• Most common use of ultrasound in medicine is diagnostic ultrasound

• The term ultrasound is very broad

  • it includes both medical and nonmedical uses of sound waves

  • and therapeutic and diagnostic applications in medical applications.

• Sonography is the term used to specify the diagnostic imaging application of ultrasound.

• Ultrasonography is a synonym for sonography.

A Brief History of Sonography

Sonography is the third-oldest imaging modality 

1. Who discovered the oldest modality?

Wilhelm Rontgen

Research began on medical applications for sonar after what world event?

World War II

Jacque and Pierre Curie (1880)

• Piezoelectric effect: allowed the construction of transducers to generate and receive sound waves in water

Paul Langevin (1915)

• Invented a sonar-type device that used echolocation to detect submarines 

Ludwig (1940s)

• Detected gallstones 

Wild

• First to ultrasound to detect tissue thickness 

• Pioneer in the development of early internal scanners

• Constructed an early prototype breast scanner with engineer John Reid

• Wild and Reid’s B-mode (brightness modulation) techniques used 2D presentations of echo-producing interfaces.

Edler and Hertz (1953)

• Explored the use of ultrasound in the heart using a technique that added a continuous moving display of the returning echoes (M-mode) to evaluate the motion of the heart valves 

Ian Donald

• Credited with discovering the first diagnostic applications of ultrasound 

• Refined techniques for obstetric procedures 

• Discovered the importance of a full bladder to visualize pelvic structures 

Holmes, Wright, and Meyerdirk (1962)

• Developed the first compound contact B-mode scanner 

A Brief History of Sonography

Kossoff

• developed a new type of scan converter that could process the returning echoes and display them as different shades of gray, depending on their intensity, and grayscale imaging was born 

Wilcox

• founded Advanced Diagnostic Research (ADR) Corporation

1. In 1980, 64 shades of gray were displayed in the static B-scanner

A Brief History of Sonography

By the mid-1980s, new and improved real-time equipment became available and started to replace the static B-scanners

The ultrasound field continued to grow as new transducer technologies continued to develop

 A Brief History of Doppler

Doppler’s Theory: changes in frequency of transmitted waves when relative motion exists between the source of the wave and an observer; the frequency increasing when the source is closer and decreasing when moved apart.

1. Who tried to disprove Christian Doppler’s theory using a musician on a train?

Christoph Hendrik Diederik; The note played was half a note higher when the train was closer, and it was half a note lower when it moved away. Ultimately, it ended uo confirming Doppler’s theory.

Baker

• designed several sophisticated, implantable flowmeters 

Baker, Rushmer, and Franklin

• developed a small, hand-held, portable, continuous-wave Doppler device for transcutaneous use

Strandess

• developed noninvasive measuring of the peripheral vascular system; his 1967 publication assigned particular waveforms to specific disease conditions.

Baker and Watkins (1970)

• developed the first pulsed Doppler unit

Baker

• developed technique for determining blood flow volume from Doppler velocimetry measurements 

The Seattle group (1974)

• first pulsed-Doppler scanner capable of combining with 2D gray-scale imaging

Now possible to use gray-scale imaging to guide the placement of the ultrasound beam for Doppler signal acquisition

Japanese researchers

• color-flow mapping techniques

Demonstrate that tissue vascularity increases in the presence of malignant conditions

1. What year did Color flow imaging become standard/popular in the US?

1987

Ultrasound: Then and Now 

• Sonography has benefited from computer and technical improvements

• New technologies allow ultrasound to diagnose pathology that had traditionally required invasive procedures or the use of potentially nephrotoxic imaging contrast agents as well as exposing the patient to radiation 

• Compact and handheld units allow ultrasound to be available in remote places in the world and even in outer space 

The Sonographer 

Early sonographers were called ultrasound technical specialists

• A technician is someone with 6 weeks to 6 months of education beyond high school 

• A technologist, by definition, is someone who specializes in a technology 

• Sonographer is specific to a person who performs medical sonography

American Registry for Diagnostic Medical Sonography (ARDMS)

In 1975, ARDMS was tasked with providing valid high-quality certification procedures for medical professionals who performed diagnostic medical sonography 

Starting in 1983, the practical and moral aspects of the examination were integrated and administered as written questions

In 1991, the ARDMS began offering computer-based examinations 

In 2016, the ARDMS restructured as a council under Inteleos, which is a new healthcare organization

1. From the chapter, list the various credentials offered by ARDMS and the year they were originally offered.

Registered Vascular Technologist credential - 1983

Registered Diagnostic Cardiac Sonographer credential - 1990

1. The first practical, oral, and written ultrasound examinations were administered in what year?

October 1974 in Winston-Salem, NC

1. The first annual sonographer awareness week occurred in

October 1991

Sonologist 

Ultrasounds may be performed and interpreted by a variety of physicians 

The term sonologist refers to any physician who interprets the ultrasound 

study 

1. Create a timeline to outline the important developments in sonography and a list of those with the contributions they are known for. 

• 1880 - Jaques and Pierre Curie: discovery of  piezoelectric effect which allowed construction of transducers to generate & receive sound waves in water

• 1915 - Paul Langevin: invented a sonar device to detect submarines using echolocation

• 1940s - Ludwig: developed first medical application of ultrasound →  detect gallstones

• 1952 - Wild & Reid: built first linear B-mode instrument; early prototype breast scanner

• 1953 - Edler & Hertz: use of ultrasound in the heart using m-mode; continuous moving display of returning echoes

• 1956/1958 - Ian Donald: credited with discovering first diagnostic applications of ultrasound; Donald & Willocks refined techniques for obstetric procedures & discovered importance of a full bladder to visualize pelvic structure

• 1962 - Holmes, Wright, Meyerdirk: developed the first compound contact B-mode scanner; close to present scanners

  • 1963 - they launched the first commercial handheld compound contact b-mode scanner

•     1972 - Wilcox: founded Advanced Diagnostic Research Corporation

• 1973 - Kossoff: developed grayscale imaging

• 1977 - ultrasound machines used scan converters that produced a grayscale image and were the main form of image production, with real-time units used to complement the static imaging

Doppler 

• 1842 - Doppler’s theory

• 1950s - Satomura developed first Doppler ultrasound device for medical diagnostic purposes

  • cardiac valve movements

• 1959 - Rushmer & Franklin - developed continuous wave Doppler to assess blood flow 

• 1960s - Strandess: developed a noninvasive way to measure vascular system 

• 1966 - Baker & Watkins developed first pulsed doppler & technique for determining blood flow volume from velocimetry measurements

• 1974 - Seattle Group - 1st pulsed doppler scan capable with grayscale imaging 

• 1980s - Japanese researches developed color Doppler; demonstrate that tissue vascularity increases in the presence of malignant conditions

• 1987 - color flow imaging became standard/popular in the US