Scientists have been fascinated by the mechanisms of acoustics, echoes and sound waves for many centuries. Numerous famous individuals, including Aristotle, Leonardo da Vinci, Galileo Galilei, Sir Isaac Newton and Leonard Euler studied these phenomena. However, it was not until 1877 that Lord Rayleigh published a description of sound as a mathematical equation in “The Theory of Sound”. A few years later Jacques and Pierre Curie discovered the piezo-electric effect, that is, an electric potential is generated when mechanical pressure is applied to a quartz crystal. Interestingly, these findings date several years before the discovery of X-rays by Conrad Roentgen 1895.

Around 1900, with the invention of the Diode and Triode, powerful electronic amplification became possible, leading to the development of a high frequency ultrasonic device by scientists Langévin and Chilowsky. This machine, called ‘hydrophone’, sent and received ultrasonic signals underwater. The Titanic disaster in 1912 and World War I accelerated investigations of underwater and airborne echo- ranging systems and antisubmarine warfare research, which lead to the beginning of SONAR (Sound Navigation and Ranging) and RADAR (Radio Detection and Ranging, using electromagnetic waves). The main industrial application of ultrasonic waves in the 1930’s and 1940’s became the detection of metal flaws.

The first application of ultrasound as a medical diagnostic tool was published in 1942 by Karl and Friederich Dussik in Vienna. The Austrian brothers attempted to locate brain tumors and the cerebral ventricles by measuring ultrasound transmission through the skull. They concluded that if imaging of the ventricles was possible, the interior of the human body could also be visualized using ultrasound. This marked the beginning of diagnostic ultrasonography in the medical field    

Over the next five decades, researchers improved and perfected ultrasound into a sophisticated diagnostic technology. Advances in computer science and electronics made the development of real-time ultrasound imaging possible. Diagnostic ultrasound is now used in two-, three- and even four-dimensional applications. It can be combined with color and power Doppler flow or other ultrasound modes and the exam can be performed with a portable machine.

The portability of real-time bedside diagnosis has made ultrasound an attractive tool for emergency medicine.  More and more emergency physicians have made bedside sonography part of their clinical practice and research activities.





Implementing this diagnostic test into our daily practice can reduce morbidity and mortality for many medical and surgical emergencies while improving patient throughput and satisfaction. In addition, emergency ultrasound education has become part of our specialty training. Residents are required to practice and implement this tool early in their careers and strict credentialing guidelines exist for emergency physicians.

The purpose of this web-based ultrasound guide is to expose more emergency physicians to this great diagnostic tool.  It was initially developed for the beginner (the medical student) with little ultrasound experience. However, it also includes advanced concepts and skills for those with more ultrasound skill. We hope this guide will encourage more physicians to implement ultrasound in their everyday clinical practice. Ultrasound is an extremely valuable diagnostic tool and with the appropriate knowledge, physicians might be able to improve its utilization compared to other diagnostic tests such as CT or MRI.