By Jan Masila
United States
Echocardiography is a non invasive cardiac diagnostic test performed using sound waves to create pictures of the heart for further interpretation by a cardiologist. The technique involves using an ultrasound machine which is used to send high-pitched sound waves through a device called a transducer which in turn picks up echoes of the sound waves as they bounce off the different parts of the heart. The echoes are converted into moving pictures of the heart which are displayed on a screen. The test is painless and safe since it poses no danger of exposure to radioactive elements to both the healthcare worker and the patient.
Application of this technology has been a test of choice for most cardiac anomalies in many leading hospitals not only here in the United States but also in other developed and developing nations across the globe. Cardiology departments in hospitals hire Cardiac Sonographers who are highly skilled individuals exclusively trained to operate echocardiography machines for the purpose of taking pictures of the hearts of patients with heart ailments in order to help in the diagnostic process.
Helpful information such as the size and shape of the heart, its pumping capacity, the location and extent of any damage to its tissues and the size of its chambers can be obtained easily using echocardiography therefore assisting cardiologists in their quest to evaluate heart functions. This test is applicable to adults as well as pediatric patients although there is a difference as pertains to the penetration power of the transducer used. Other alternative ways of performing echocardiography include transesophageal and transthoracic echocardiography.
The origin of this technology can be traced back to 1953 when Inge Edler a cardiologist practicing at Lund University in Sweden. Edler was in charge of the cardiology department of the medical clinic at the University and had a friend called Hertz a physicist with a long standing interest in using ultrasound for the measurement of distance. At that particular time, Edler used the M-Mode technique for a preoperative study of mitral stenosis and mitral regurgitation which marked the beginning of the use of ultrasound. He named the technique ultrasound cardiography.
This new discovery gained popularity and cardiologists around the world adopted it as a diagnostic tool and further research was done culminating into the discovery of Doppler, 2-dimensional echo, contrast, and transesophageal echocardiography. Regardless of any further discovery; Edler who lived between the years of 1911 and 2001 maintains his recognition and distinction as the father of echocardiography.
The machine used by Edler and Hertz to measure M-Mode was a bulky piece of equipment compared with the models available in the market today. Just like any other electronic equipment; echocardiography machines have evolved from bulky stationary machines to sleek and even portable machines.
Current echocardiography examination is based on real-time two dimensional images. M-mode technique is now relegated to a supplemental examination although it is still being used to make routine measurements which are better obtained directly from two-dimensional pictures. M-Mode has the advantage of having an enhanced temporal resolution which makes taking these measurements clear and easy.
To back this technology up; some of the leading manufacturers of Ultrasound machines namely Philips, GE, HP, Sequoia and Acuson have been in the forefront making user friendly portable machines which make it possible to perform studies at the patient’s bedside. Philips specifically has been very successful with its iE33 which offers an interactive touch screen and a more user friendly operator panel. The machine has 3D technology capability but for the most part many institutions still continue to use its 2D package due to the fact that not very many sonographers are conversant with 3D and 4D which calls for further expenditure in training.
Lately, most of the medical imaging centers around the nation have adopted three dimensional displays and echocardiography is not to be left behind. Real time three dimension echo imaging is in its young stages and many sonographers and physicians are still learning its strengths and weaknesses. Interestingly though; the transthoracic three dimensions echo has shown value in accurately assessing the contractile function of the left ventricle and the transesophageal three dimensions approach has helped in improving the visualization of valve pathologies.
Echocardiography machines are now outfitted with the hardware and software to perform real time three dimensions echocardiography imaging. Beside 2D images; Color Doppler which is a component of the 2D technology is applied to shed light on further diagnostic facts. With color in place, a sonographer is able to show direction of blood flow as well as pinpoint with much accuracy the existence and position of cardiac shunts such as Ventricular Septal Defects (VSD’s), Atrial Septal Defects (ASD’s), or even muscular defects. Tricuspid and mitral regurgitations including pulmonic and aortic insufficiencies have been successfully diagnosed by the use of Color Doppler. This eliminates guess work and saves time that would have otherwise been used interrogating an area suspected to be having these shunts.
Storage of echocardiography data is one area that is as important as the diagnostic process itself. Cardiologists always make follow up on treatment of their patients so it is important for them to be able to retrieve data for comparison or even simple reference. With the old technology, storage was done on bulky tapes which occupied large space and whose quality deteriorated with time especially when they are played many times. This deterioration led to the stored images losing their quality thereby becoming unreliable stored data.
Modern technology has ushered in digital storage called Digital Archiving which is more efficient and maintains pictures quality as they are stored in DVD’s which have a better resolution and can hold many files therefore making it possible to preserve filing space. They are easy to carry and can be used in different work stations hence providing convenience and easy retrieval of data whenever needed. Digital recordings can also be placed on a computer network and made available at numerous stations including satellite clinics. Examinations stored in this form are retrieved in less than 30 seconds and are available 24 hours a day 7 days a week.
Most clinical facilities operate in a networked system whereby a physician can view the pictures being taken as they stream in. This is a big milestone because it avoids the possibility of repeating a test because the physician is able to view and request for more pictures as he or she deems necessary. Another advantage of networked technology is that it saves time that would have otherwise been used entering information in the machine manually.
Post processing of imaged data is possible with 2D imaging technology. This ensures correction and maintenance of correct data for archiving. The flexibility that this maneuver comes with makes it possible for adjustments to be done without interfering with the quality of the data to be archived.
The companies involved in manufacturing of ultrasound machines have pumped a lot of money in research to outdo each other with innovative technologies and this has provided sonographers with variety of choices. GE and Philips have dominated the market although the competition is stiff from other competitors. As evidence of this unending competition, it is worth noting that the trend with which we continue to get a wide variety of transducers, frequencies, and many different and unique applications potentially available means that the ultimate echocardiography instrument and examination is not with us here yet. There has been a lot of jostling and fancy advertisements fronted by these leading manufacturers with each one of them trying to cut an edge for itself and stake a claim of the trophy of innovation in the ultrasound industry.
Information available on Philips website regarding their signature product iE33 suggests that it is the right machine to use to evaluate Cardiac Motion Quantification (CMQ) because it increases the accuracy of LV function and wall motion measurement. Further, Philips states that the new CMQ speckle tracking algorithm available in the machine makes strain analysis a useful tool in assessing presence and extent of LV disease including multiple strain and strain rate parameters and longitudinal strain.
On the other hand, GE without wanting to be left behind in this has staked a claim as the company holding the key to the future of ultrasound fronting its Vivid E9 as the ultrasound machine specifically made for 4D technology. Other advantages the company associates with this machine are that it is ergonomically easy, highly mobile, easy key board storage and convenient data management among others. It is also worth noting that GE has an array of other versions of ultrasound machines all of which it claims offer consumers the best bargain and quality.
It is not too early to predict but it is almost certain that the transducer technologies currently under development may change echocardiography drastically. Two-dimensional arrays of transducers provide the potential for real-time, three dimensional and four dimensional imaging. Made by the use of silicon chip technology; the new transducers will play an integral role in the development of the personal echocardiograph device.
Research and development in this sector has not been a preserve for the leading companies associated with the manufacture of ultrasound machines only as other players albeit small are emerging with even more sophisticated products some of which are hand held devices. In fact, we continue to me mesmerized by the frequency by which new devices are being made adding up to whatever the market has to offer at the moment. It was only last week that Apple Inc launched an application for echo testing which converts the iPhone to a mobile ultrasound machine. This is definitely technology of the cutting age which serves to make us see how advanced this technology has come to be.
Echocardiography has emerged as one of the most respected careers in the healthcare industry. Its popularity has grown due to its reputation as a painless yet very effective diagnostic test. The fact that this test does not expose a patient to radiation is a plus as many ailments are worsened by continued exposure to radiation while carrying out diagnostic tests.
Regulation through a professional body called American Society of Echocardiography (ASE) has helped streamline echocardiography profession by setting standards and guidelines to be followed in performance of cardiograph tests. In addition to that, the American Registry for Diagnostic Medical Sonography (ARDMS) has taken up the task of ensuring regulation in terms of training for one to qualify as a registered cardiographer. Passage of a board examination set by ARDMS before being registered ensures that patients are placed in the safe hands of qualified professionals in the field. This comes with its own drawbacks though as going to school for sonography can be expensive and time consuming. Lack of many accredited colleges and inadequate facilities in the available colleges makes it hard for many people interested in pursuing a career in ultrasound to secure admission.
Overall; echo technology is here to stay and the future of this diagnostic technique is obviously very bright. The amount of money put in place by research companies and the continued supply of reference materials available in the market plus the continued demand for these services is a clear indication that this is definitely a growing field which has evolved over the years to claim a leading spot in terms of reliance and effectiveness in detecting and diagnosing heart diseases.
