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A Digital Echocardiographic Laboratory
EDITORIAL
A Digital Echocardiographic Laboratory Harvey Feigenbaum, MD, Indianapolis) Indiana
In this issue of the JOURNAL OF THE AMERICAN SoCIETY OF ECHOCARDIOGRAPHY, Drs. Thomas and Khandheria review some of the basics and ter minology used with digital formatting of medical images. This information is important as we enter an era of digital recording and storage of echocardio graphic images, or digital echocardiography. We at Indiana University have been using digital recordings of echocardiograms for nearly 10 years. Over the course of this experience we have learned to appreciate the many advantages that this technol ogy can have in the everyday use of echocardiogra phy. Having the images in a digital format provides the ability to manipulate the images. One can alter the gray scale or any other parameter. Quantitation is obviously easier with a digital recording. The screen can be divided so that one can display multiple images simultaneously. In our experience the most important use ofdigital echocardiography is the ability to provide a concise summary of the echocardiographic study. Our cur rent dependence on videotape has been a major lia bility in our ability to utilize and disseminate echo cardiographic information. There is so much infor mation on the videotape that it takes 10 to 15 minutes, or sometimes longer, to review one study. It takes time to find a specific patient on a 2-hour videotape. Each sequence is displayed for a finite pe riod oftime. One does not have the option ofviewing it at one's leisure. These limitations are particularly troublesome when trying to show echocardiographic information to our colleagues, to the patient, or to the patient's family. Videotape is satisfactory for the routine interpretation of echocardiograms, but one cannot show unedited video recordings at confer ences or conveniently demonstrate them to referring From the Indiana University Hospital. Reprint requests: Harvey Feigenbaum, MD, Indiana University Hospital, 926 West Michigan St., Room 5420, Indianapolis, IN 46202-5250. JAM Soc ECHOCARDIOGR 1994;7:105-6. Copyright 1994 © by the American Society ofEchocardiography. 0894-7317/94$1.00 + .10 27/l/52185
physicians or surgeons. It is almost impossible to show an echocardiogram to a layperson, such as a patient, with videotape. Last and most important, videotape makes the assessment of serial studies te dious and impractical. Because echocardiography is a noninvasive, painless, harmless, and relatively low cost procedure, it is an ideal examination for detect ing any cardiac changes due either to natural history or to therapy. Unfortunately it is very cumbersome to make such an assessment with videotape. With our digital echocardiography program at In diana, evaluating serial studies and showing echo cardiograms have become very convenient. It takes from 5 to 20 seconds to retrieve a complete study for viewing depending on the size of the examination and the medium from which it is being recalled. Dig ital recordings can be placed in a computer network and be available 24 hours a day, 7 days a week, at multiple stations throughout the hospital. Images can be transmitted via modems to referring hospitals or to outpatient facilities. With the corning of the digital age it is important to have some basic understanding of this technology. The article by Drs. Thomas and Khandheria provides important background information. The practical ex perience gained from our own laboratory suggests that it is also important to recognize the purpose of the digital examinations. All too often we in echo cardiography are primarily concerned about "pretty pictures," and we sometimes forget the real purpose of our examination, which is to provide clinical in formation. A fundamental principle in ultrasonic im aging is the fact that compromise is necessary with every aspect of echocardiography. For example, we frequently make a trade-off between the depth of a two-dimensional examination and the frame rate. We make numerous compromises when we use color flow imaging. We mut also make compromises when recording digitally. There is a natural tendency to have digital record ings replace videotape. We want to record a complete echocardiographic study digitally, as we currently do with videotape. Unfortunately this approach requires a tremendous amount of digital memory. Although 105
106 Feigenbaum
memory is becoming less costly and more readily available, we still have not reached a point where we can totally disregard how much memory we are us ing. For example, if we were to record complete car diac cycles with 512 X 512 pixel resolution, 256 shades of gray, full color and full images, this ap proach would require 256 times more digital mem ory than what we have been using in our laboratory. This means that it would take 256 times longer to retrieve images and to transmit them via modem compared with our current studies. We obtain this 256:1 ratio with a combination of both digital and clinical compression. Admittedly we started with a minimum number of frames or cells because initially that was all that we had. However, when digital memory became more readily available, we found that the added cost in time and memory did not provide sufficient benefit to warrant changing our approach. Computer tech nology is changing so rapidly that the availability of even greater amounts of digital memory and increas ing speed is a certainty. It is highly probable that we will ultimately change our current routine and record more information. The message, however, is not whether or not we can record more digital infor mation. I feel that it is increasingly important to remember that our goal is to record useful clinical information and not necesssarily do everything that is technically feasible for aesthetic value. Whatever
Journal of rhe American Society of Echocardiography January·February 1994
we do, it must be very quick and convenient, and above all it must be inexpensive. Digital recording is a nonreimbursable feature added to an echocardio graphic laboratory. Ifthis approach does not enhance a laboratory's efficiency and credibility by providing a better means ofcommunicating with our customers (i.e., referring physicians and patients), then we can not justify the added cost. I am convinced that digital echocardiography can be an important factor in the new era of cost con tainment. This recording approach should enhance the operating versatility and efficiency of an echo cardiographic laboratory and will mi.doubtedly im prove our ability to communicate with our col leagues. When third-party carriers make decisions as to whether or not echocardiograms should be per formed, they will consult our customers, not us. We must elicit an increasing amount ofsupport from our referring physicians. This support will come more easily if they fully understand what we are doing. The old adage, "a picture is worth a thousand words" has never been more true than with an echocardio graphic examination. If our colleagues have only a verbal or written report, the implication to the phy sician is "trust me." Demonstrating an abnormality to a referring physician increases one's credibility a thousandfold. This type ofcommunication is increas ingly necessary at this critical time in the practice of medicine.
A Digital Echocardiographic Laboratory Harvey Feigenbaum, MD, Indianapolis) Indiana
In this issue of the JOURNAL OF THE AMERICAN SoCIETY OF ECHOCARDIOGRAPHY, Drs. Thomas and Khandheria review some of the basics and ter minology used with digital formatting of medical images. This information is important as we enter an era of digital recording and storage of echocardio graphic images, or digital echocardiography. We at Indiana University have been using digital recordings of echocardiograms for nearly 10 years. Over the course of this experience we have learned to appreciate the many advantages that this technol ogy can have in the everyday use of echocardiogra phy. Having the images in a digital format provides the ability to manipulate the images. One can alter the gray scale or any other parameter. Quantitation is obviously easier with a digital recording. The screen can be divided so that one can display multiple images simultaneously. In our experience the most important use ofdigital echocardiography is the ability to provide a concise summary of the echocardiographic study. Our cur rent dependence on videotape has been a major lia bility in our ability to utilize and disseminate echo cardiographic information. There is so much infor mation on the videotape that it takes 10 to 15 minutes, or sometimes longer, to review one study. It takes time to find a specific patient on a 2-hour videotape. Each sequence is displayed for a finite pe riod oftime. One does not have the option ofviewing it at one's leisure. These limitations are particularly troublesome when trying to show echocardiographic information to our colleagues, to the patient, or to the patient's family. Videotape is satisfactory for the routine interpretation of echocardiograms, but one cannot show unedited video recordings at confer ences or conveniently demonstrate them to referring From the Indiana University Hospital. Reprint requests: Harvey Feigenbaum, MD, Indiana University Hospital, 926 West Michigan St., Room 5420, Indianapolis, IN 46202-5250. JAM Soc ECHOCARDIOGR 1994;7:105-6. Copyright 1994 © by the American Society ofEchocardiography. 0894-7317/94$1.00 + .10 27/l/52185
physicians or surgeons. It is almost impossible to show an echocardiogram to a layperson, such as a patient, with videotape. Last and most important, videotape makes the assessment of serial studies te dious and impractical. Because echocardiography is a noninvasive, painless, harmless, and relatively low cost procedure, it is an ideal examination for detect ing any cardiac changes due either to natural history or to therapy. Unfortunately it is very cumbersome to make such an assessment with videotape. With our digital echocardiography program at In diana, evaluating serial studies and showing echo cardiograms have become very convenient. It takes from 5 to 20 seconds to retrieve a complete study for viewing depending on the size of the examination and the medium from which it is being recalled. Dig ital recordings can be placed in a computer network and be available 24 hours a day, 7 days a week, at multiple stations throughout the hospital. Images can be transmitted via modems to referring hospitals or to outpatient facilities. With the corning of the digital age it is important to have some basic understanding of this technology. The article by Drs. Thomas and Khandheria provides important background information. The practical ex perience gained from our own laboratory suggests that it is also important to recognize the purpose of the digital examinations. All too often we in echo cardiography are primarily concerned about "pretty pictures," and we sometimes forget the real purpose of our examination, which is to provide clinical in formation. A fundamental principle in ultrasonic im aging is the fact that compromise is necessary with every aspect of echocardiography. For example, we frequently make a trade-off between the depth of a two-dimensional examination and the frame rate. We make numerous compromises when we use color flow imaging. We mut also make compromises when recording digitally. There is a natural tendency to have digital record ings replace videotape. We want to record a complete echocardiographic study digitally, as we currently do with videotape. Unfortunately this approach requires a tremendous amount of digital memory. Although 105
106 Feigenbaum
memory is becoming less costly and more readily available, we still have not reached a point where we can totally disregard how much memory we are us ing. For example, if we were to record complete car diac cycles with 512 X 512 pixel resolution, 256 shades of gray, full color and full images, this ap proach would require 256 times more digital mem ory than what we have been using in our laboratory. This means that it would take 256 times longer to retrieve images and to transmit them via modem compared with our current studies. We obtain this 256:1 ratio with a combination of both digital and clinical compression. Admittedly we started with a minimum number of frames or cells because initially that was all that we had. However, when digital memory became more readily available, we found that the added cost in time and memory did not provide sufficient benefit to warrant changing our approach. Computer tech nology is changing so rapidly that the availability of even greater amounts of digital memory and increas ing speed is a certainty. It is highly probable that we will ultimately change our current routine and record more information. The message, however, is not whether or not we can record more digital infor mation. I feel that it is increasingly important to remember that our goal is to record useful clinical information and not necesssarily do everything that is technically feasible for aesthetic value. Whatever
Journal of rhe American Society of Echocardiography January·February 1994
we do, it must be very quick and convenient, and above all it must be inexpensive. Digital recording is a nonreimbursable feature added to an echocardio graphic laboratory. Ifthis approach does not enhance a laboratory's efficiency and credibility by providing a better means ofcommunicating with our customers (i.e., referring physicians and patients), then we can not justify the added cost. I am convinced that digital echocardiography can be an important factor in the new era of cost con tainment. This recording approach should enhance the operating versatility and efficiency of an echo cardiographic laboratory and will mi.doubtedly im prove our ability to communicate with our col leagues. When third-party carriers make decisions as to whether or not echocardiograms should be per formed, they will consult our customers, not us. We must elicit an increasing amount ofsupport from our referring physicians. This support will come more easily if they fully understand what we are doing. The old adage, "a picture is worth a thousand words" has never been more true than with an echocardio graphic examination. If our colleagues have only a verbal or written report, the implication to the phy sician is "trust me." Demonstrating an abnormality to a referring physician increases one's credibility a thousandfold. This type ofcommunication is increas ingly necessary at this critical time in the practice of medicine.