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Lazzaro Spallanzani (1729-1799) exemplified echo reflection by demonstrating how bats use inaudible sound reflection to navigate. Bats send sound waves outward and determine the distance of objects based on the waves they receive (bounced back) from objects. Today, we commonly know this process as SONAR (Sound Navigation and Ranging). -
According to the US Bureau of Labor Statistics, an estimated 68,750 diagnostic medical sonographers are employed in the United States. Entry to the field may require an associate's or bachelor's degree depending on the hiring region. Beginning in the 1700s, scientists contributed much research and experimentation, leading to modern-day ultrasound technology. Echocardiography is based on the concept of processing inaudible sounds to create an image of the heart.
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Jean-Daniel Colladon proved the speed of sound is faster underwater than through the air. Water is used as a similar medium to the human body. The sound speed through the water is 1,435 meters/second, close to today's standard in applying ultrasound physics. Pictured is his famed experiment measuring the speed of sound by gonging a church bell underwater 10 miles away from the receiver. -
During the 1880s, brothers Pierre and Jacques Curie discover the Piezo-Electric Effect, which converts kinetic or mechanical energy, through crystal deformation, into electrical energy. The same piezoelectric technology is used in building ultrasound probes. -
SONAR technology (Sound Navigation and Ranging) uses echolocation to determine the distance and direction of objects. Water-borne diagnostic ultrasound appears in 1918 by Paul Langevin and Constantin Chilowski. The same technology was used in an earlier, non-electric design by Reginald Fessenden. After the 1912 sinking of the Titanic, SONAR was used to detect icebergs as well as enemy submarines during World War I. -
Between the 1940s and 1960s, ultrasound machines took on varying forms. One of the earliest forms used a horse bath in which a person would be fully submerged. Ultimately the first handheld ultrasound transducers attached to large machines are developed during this period.
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Pictured is C.R. Cushman in 1950, submerged in a horse trough. Scientists were interested in mapping the human body using ultrasound. Remember, sound waves move faster through water than through air. Today we use a water-based gel on the tip hand-held ultrasound probe. Pictured is one of the earliest experiments of producing an ultrasonic image of the human body. -
October 29, 1953, the Seimens Ultrasound Reflectoscope records the first moving pictures of the heart. Ultrasound Cardiography UGC is born. Pictured are Inge Elder and Carl Hertz with the Seimens Ultrasonic Reflectoscope. -
In 1956, the first clinical application using diagnostic cardiac ultrasound was Inge Edler's diagnosis and follow-up of patients with pericardial effusion. Both Edler and Carl Hertz, are credited with inaugurating the field of diagnostic cardiac ultrasound. -
An experiment by John Wild, testing to see if women could be screened for breast cancer via ultrasound. Wild is pictured submerging his chest in water as the machine takes pictures. Ultrasound has been proven to reveal abnormalities in human tissue. -
Cardiac ultrasound and the machines used to conduct the exams looked primitive compared to today's modern designs. Pictured on the left is the ACUSON SC2000 by Seimens. -
The first successful attempt was in 1976 by Dr. Leon J. Frazin. A Transesophageal Echocardiogram requires a special probe (TEE Probe) inserted by mouth down into the esophagus where the transducer sits behind the heart. Pictured are early model TEE probes and the apparatus associated with them. The diagram illustrates the probe's placement into the mouth, down the esophagus, and behind the heart. -
Ultrasound machines in the 1980s were comparatively small compared to their mechanical giant predecessors. Ultrasound once required all of the equipment you see pictured. In the following slide, we will see a side-by-side comparison of a more modern mobile unit and a room full of early ultrasound equipment next to an exam bed. -
It used to take all of the equipment you see in the image on the right to conduct a bedside echocardiogram. Slowly but surely, manufacturers began to build more mobilized units to visit patients in their hospital rooms. -
Echocardiograms have become specialized to investigate particular heart problems. Standard echoes evaluate the general structure and functions of the heart. Stress echoes evaluate the heart's performance when under stress. Echo-guided pericardiocentesis help physicians place a large needle into the pericardium to drain fluid. ICE echoes actually enter the heart via a catheter. Pictured is a treadmill stress echocardiogram. -
Seen in this photograph is a heart administered with a microbubble enhancement agent. These types of enhancements allow the technologist to evaluate the heart for wall motion abnormalities or blood clot formation. -
This slide features Philip's Truvue ultrasound technology utilized in this picture of a semilunar valve opening and closing. The image seen here was likely produced by a TEE procedure. -
TEEs require placing the probe into the mouth to access the esophagus. The esophagus is located directly behind the heart's left atrium, where the ultrasound probe can closely evaluate important structures within the heart. TEE's are used in many implantable cardiac device procedures. -
Cardiovascular ultrasound as an allied health profession has become packed with many diagnostic applications and technologists who are specialized in performing the exams. Medical spaces that feature cardiac ultrasound range from emergency medicine, bedside inpatient exams, outpatient procedures, and even major cardiac repair procedures. Career outlooks according to the bureau of labor predict a 12% growth in the field adding 15,600 cardiovascular and general sonographers between 2019 and 2029.