Medical Ultrasound History and Echocardiography Application

Introduction

There are many names that are used to describe an ultrasound including sonogram, diagnostic sonography or an ultrasonography (Leonard 89). Medical sonography (ultrasonography) is an ultrasound-based imaging technique used in diagnostic medicals that are utilized in visualizing small and delicate body organs such as muscles, tendons and many internal organs to capture their size, structure and any pathological lesions using the real time tomographic images (Chaudhuri 317). A sonogram utilizes high frequency sound waves to form the image of certain parts of the inside of a human body including the stomach, liver, heart, tendons, muscles among other things (Vaezy 379). This technique uses sound waves as opposed to radiation, hence is considered safer because it does not harm the body (Hoskins 8). Ultrasounds can be used to detect any problems within the parts of the body that are examined. The technology in this case is usually less expensive and mobile, particularly when compared with other modalities such as the MRI and the CT (magnetic resonance imaging and computed tomography) (Alter 56). Hence it is the most popular diagnostic tool currently in the world of modern medicine.

History of Ultrasound

The history of ultrasound dates back to the 19^th and 20^th century, especially in Europe. Specifically, the during the First World War, the French government had assigned a physician,  Paul Langevin, the duty of inventing a device that was capable of detecting the underwater submarines belonging to its enemy using the high frequency sonar.

Over the decades that followed, many experiments were carried out within the military to assess the potential of scientific and industrial ultrasound technology. Despite all these developments being put forward, it was not until the 1940s that the use of an ultrasound as a diagnostic medical tool emerged. This happened when the neurologist and psychiatrist Karl Dussik from the University of Vienna developed the concept of the ultrasound. During this period, while working with his brother, the scientist used an ultrasound beam to look for brain tumors and also locate cerebral ventricles as well as cavities in the brain that contained cerebro-spinal fluid.

Other pioneers from America and Europe also emerged with time and broadened the scope of the diagnostic medical ultrasound during the following five decades (Mamou 19-24). Besides using it to detect a wide array of medical conditions, they also made great advances in hardware and imaging quality. In the 1950s, Ian Donald, while working in Glasgow, became the first person to use the ultrasound to monitor fetal development (Rantanen 1) During the same period, he also published a seminal diagnostic study in 1958 having worked with a group of researchers to invent a prototype ultrasound machine which was specifically designed and dedicated to the task of medical diagnosis. With time, manufacturers were able to use technology advancement to design smaller and portable ultrasound machines.

A development that resulted in future machines taking sharper, clearer and high quality pictures. Further developments and innovation eventually resulted in the invention of the two, three and four dimensional ultrasounds, in addition to the dropper imaging. This latter invention assisted medical professionals and even patients to better fathom the indications and revelations of ultrasound tests. By the 1970s, medical profession had already embraced sonography as a special and distinct occupation and in 1973, the United States department of education even recognized the field as a profession with its own rights. Since this period, sonography as a field and profession has grown immensely and attained its present status in the medical field.

Uses and Applications of a Medical Sonogram

Medical sonography is utilized in various medical studies which include anesthesiology whereby the ultrasound technology guides anesthetists when injecting needles to administer local anesthetic solutions near the nerve of patients. At the same time, this technology is utilized in echocardiography to detect any dilations on the paths of the heart and also check whether the heart and the valves are functioning properly. It is further used in the emergency medicine and emergency departments to expedite the care of the patients who might be experiencing gallstones or feeling intense pain in the upper abdomen. The ultrasound technology is also commonly used in managing pregnancy by determining important things such as the fetal heart of a baby, expected delivery time and the location of the fetus. In fact, this technology can be used to indicate the sex of a baby during pregnancy (Bruno 325). The sonogram has been used and applied in many medical care areas including Neonatology, Neurology, Otolaryngology and gastroenterology fields.

Working Principle of an Ultrasound

An ultrasound works by transmitting high frequency sound pulses (echoes) into a patient’s body and the sound waves in turn travel through the body into different tissues at an average speed of 1540 m / s, even though this speed is different depending on the type of the tissue. Science shows that the speed of the ultrasounds through fat is 1459m/s while through the bones it is approximated at 4080m/s. As sound passes through the tissues with different acoustic properties, there is a reflection of the proportionate of the sound (Hoskins 8). The boundaries between two different tissues are known as acoustic interfaces and the amount of sound reflected through the acoustic interface is determined by the type or properties of materials on the sides of the interface.

Echocardiography

Echocardiogram commonly abbreviated (ECG) is an ultrasound that is carried out at the heart that utilizes the process of echocardiography. In today’s society, it has been used in many instances in diagnosing, managing and also following up of patients who may be experiencing heart problems. In cardiology, echocardiography is one of the most common diagnostic tests because it can yield a lot of vital information which may include the size and the shape of the heart, pumping capacity of the heart, location and the extent to which a heart tissue may be damaged. In addition this test can also reveal other features such as the estimates of heart functions which may encompass the calculation of the cardiac output as well as the ejection fraction. Echocardiography can help to detect cardiomyopathies such as the hypertrophic cardiomyopathy and dilated cardiomyopathy among other problems. The echocardiography is also an important diagnostic tool that can be used to test chest pains and other symptoms that are connected to heart ailments. One of the most essential merits of the echocardiography is the fact that it is noninvasive hence it does not involve the breaking of the skin and, as such carries neither risks nor side effects.

Applications of Echocardiography

As explained, the echocardiogram is a noninvasive sonograph analysis of the heart and big vessels which mostly differs from the ordinary ultrasound because of its capacity to provide pertinent information on the human anatomy, haemodynamics, functions, both dynamic systolic and diastolic of the heart as well as regarding the big vessels. It is of high importance to note that echocardiogram can either be performed under a resting condition as a baseline comprehensive assessment or even under controlled stress conditions with the aim of carrying out functional assessment of the significance of the vascular lesion. There are different kinds of echocardiograms that can be utilized in the creation of pictures of the heart and these include the transthoracic echocardiography, which is said to be the most common type of echocardiogram test (St 203).

It entails the sinologist placing a special device on the chest, which then transmits special sound waves through the wall of the chest to the heart whereby the waves are resounded back to a computer and automatically converted into pictures. Stress echocardiography is usually carried out as the part of the stress test where one is instructed to run or take some medicine to make the heart beat faster, after which the technician takes the echo from the heart just before the exercise or taking the medicine and immediately after the exercise of medicine has been taken. This type of echocardiography can be helpful in diagnosing some problems such as the coronary heart disease.

Transesophageal echocardiography is the technique where a transducer attached to the end of a flexible tube is guided down the throat into the esophagus allowing a sonologist to obtain a better detailed picture of the heart. Fetal echocardiography on the other hand is used to test the movement of the heart of an unborn baby and is recommended on 18th to 22nd weeks of pregnancy. Finally, a three dimension echocardiography assists in the creation of 3D images of the heart as it takes the echo and is popularly used to diagnose various heart problems in children as well as in planning and monitoring the heart valve surgery.

Chest pains can result from various issues which may vary from coronary artery disease, aortic dissection, pulmonary embolism and peptic ulcer disease, reflux esophagus among other factors that involve muskeletal pain, neuritis, pleurities, gallstones, psychosomatic and pericarditis. In such cases, many of the clinicians need to rule out the coronary heart disease and the aortic dissections because they are treatable and exhibit most of the presenting symptoms. A thorough echocardiogram is usually carried out to give clues and diagnosis of acute syndrome or any other possible infection that may be found in the patient. If the ECG reveals that there is any abnormality and thinning around the regional wall motions, then it is assumed that the old myocardial infarction is at rest.

Recently, numerous manufacturers have began the production of the harmonic imaging within echocardiography machines. The reason for introduction of such imaging is the fact that reflected sound waves may contain  second degree harmonics which are in the form of wavelengths but have a half life or half of the wavelength magnitude, hence the harmonic imaging aids the system by emitting sonography energy at a frequency that is generally of a lower rate. Harmonic imaging also helps to retain the normal frequencies and this does not affect the quality of the image. Nevertheless, care must be taken during its application as continuous usage can cause unusual textures on the image.

Contrast echocardiography is yet another emerging application that is utilized in the demonstration of shunts through the intravenous injection of agitated saline (Walsh 198). The contrast agents are produced commercially and are made up of free and encapsulated gases bubbles. The tiny air bubble enhance the backscatter thus assisting in highlighting the tissue that has the contrast agent. This technique is used in diverse applications including filling of cavity in case blood is visualized in the left ventricle because the borders between the blood and the myocardium are visibly highlighted. Contrast is also used in myocardial perfusion where it is introduced through the intracoronary injection and helps to regulate the changes that are linked with the increased workloads as well as delineating the myocardium that is supplied by each coronary artery.

Contrast is further used in enhancing the flow in the heart whereby it is injected to enhance the number of reflectors and thereby increases the intensity of the resultant spectral trace. It is also essential in the studies regarding the dropper. The three dimensional echocardiography is mostly used together with both the transoephagueal and intravascular ultrasounds and it assists in providing real time imaging of the cardiac structure as well as its functioning. Since it is noninvasive, it is more effective in describing and communicating the abnormalities to specialists and can also help to better identify the location of the structural defects of the heart in connection to each other and other heart structures. Therefore, this technique gives accurate descriptions that can even be utilized when undertaking surgical repair.

Echocardiography is recommended for purposes of initial diagnosis where there is a noticeable change in the clinical status of the patient and as such it is not wise to overuse this test, unless there is a noticeable deteriorating change in the condition of the patient based on the results of the testing. Echocardiogram is essential because it helps the doctor to easily conduct diagnosis, monitoring and analysis of the heart conditions for any abnormal heart rates, heart murmurs, infection in the heart, sources of blood clots and pulmonary hypertension among other problems.

Works Cited

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Chaudhuri, Zia, and Murugesan Vanathi. Postgraduate Ophthalmology. New Delhi, India: Jaypee Brothers Medical Publishers, 2012. Print.

Hoskins, P R, Kevin Martin, and Abigail Thrush. Diagnostic Ultrasound: Physics and Equipment. Cambridge, UK: Cambridge University Press, 2010. Print.

Leonard, Peggy C. Quick & Easy Medical Terminology. St. Louis, Mo: Elsevier, 2014. Print.

Mamou, Jonathan, and Michael L. Oelze. Quantitative Ultrasound in Soft Tissues. , 2013. Print.

St, John S. M, and Susan E. Wiegers. Echocardiography in Heart Failure. Philadelphia, PA: Elsevier/Saunders, 2012. Internet resource.

Vaezy, Shahram, and Vesna Zderic. Image-guided Therapy Systems. Boston, MA: Artech House, 2009. Internet resource.

Walsh, Catherine A, and Peter Wilde. Practical Echocardiography. London: Greenwich Medical Media, 1999. Print. 198.