"...Accepted into the Smithsonian Permanent Research Collection of Information Technology."
Long Summary The clinical concept was to have a facility which offered full cardiac care twenty-four hours a day with all aspects of the care computerized to the fullest extent possible. Consistent with this concept, it was necessary to identify the mechanisms required to move the massive amounts of digital information acquired in digital cardiac imaging procedures. The rapidly evolving digital imaging technology was the area where the most dramatic and beneficial advancement could be incorporated into the new cardiac cath laboratories. It was necessary to first establish what performance digital imaging technology was capable of as well as how the information could be stored/archived to meet the legal requirements of medical information. The second step was to identify the technical solutions to the clinical needs and provide this performance in a more cost effective manner. The six (6) digital Toshiba cardiac imaging systems selected and installed in the catheterization laboratories provided improved filmless digital imaging and archiving for peripheral vascular and intracranial imaging. These digital imaging systems used a Charge Coupled Device (CCD) to acquire 1024 x 1024 digital images, which were displayed on high resolution (nominally 1024 x 1024) progressive image monitors. Each cardiac digital image is comprised of nominally 1 Mbyte of 14 bit data, and for adults is typically acquired at 30 images per second with neonatal and pediatric studies often at 60 images per second. A clinical diagnostic study is typically about 2000 images and an interventional study ranges from 3500 images to as many as 7500 images. The rate of data acquisition is daunting in terms of data handling and the amount of digital data is massive. The combination of the rate and volume of digital data presented major technological challenges, since the data had to be stored/archived essentially simultaneously with the acquisition. An inability to archive the data in a manner transparent to the clinical staff would render the digital imaging systems unworkable. (Anecdotally, it was found that a delay of even one minute was unacceptable to the cardiologists.) The modality selected for archiving the digital image data had to be fast, simple to use and relatively inexpensive since it had to be possible to archive a study individually as well as maintain a master archive of all studies. The diagnostic studies have at least 2 Gbytes of data and interventional studies have as much as 7.5 Gbytes of data. The data archive modality selected was compatible with Toshiba cardiac digital imaging systems and utilized a video broadcast quality digital tape cassette system which was modified and interfaced by Toshiba to the Sony D-2 digital tape recorder system. In addition to the digital imaging systems in the catheterization laboratory, it was necessary to have digital image review stations as the traditional cardiac cine 35 mm film was no longer available to be viewed post procedure. The digital image review stations were developed by Toshiba based on the Sony D-2 digital tape recorder and allowed the images to be displayed with essentially the same image quality as that displayed on the digital cardiac imaging system in the cardiac catheterization laboratories. The Toshiba digital cardiac imaging systems were at the leading edge of technology and many national core research centers did not have this digital imaging technology. Thus, it was necessary to develop a unique device to make cine film images of the digital cardiac images. This task was accomplished under the direction of Dr. Morgan thus allowing the new Methodist Heart Center clinicians to participate in core research centers providing the clinical digital imaging studies on cine film until such time as the centers were capable of receiving and viewing digital cardiac images from different types of systems. As an example of the technical performance of these systems, Dr. Robert Wey, Cardiologists of Lubbock, is the Principal Investigator on an Investigational Device Trial for carotid stenting using these digital imaging systems. The protocol requires quantifying the stenosis pre and post stent deployment which can only be satisfied using the high resolution and precision of these digital cardiac imaging systems. The computer controlled digital imaging and archive systems dramatically accelerated the diagnosis of patient cardiac disease and the related care including non-interventional as well as interventional care delivery with the associated improvement in quality of care provided. Another significant feature of the digital imaging system was that a single study or set of digital images could be conveniently recorded on standard VHS tape retrospectively as desired. This made it convenient and inexpensive to provide a copy of the study immediately available to the referring physician and to the patient to take with him for his own personal record. The high performance of the Toshiba digital cardiac imaging systems makes them extremely susceptible to their facility environment. In fact, it was determined that the ceiling mount for the digital imaging assembly had to have additional dampening installed to nullify the new facility motion in the low frequency range (building vibrations).
Benefits The digital cardiac imaging systems allows instantaneous viewing of each diagnostic image sequence with high image quality. This is dramatic when compared to the time necessary for a study using cine film imaging to be available for review by the cardiologist. Because the images are available instantaneously, there is no delay encountered in analyzing the study and immediately beginning the necessary clinical therapy. This is in sharp contrast to cine film based procedures, where it is not uncommon to wait 15 to 20 minutes after the study has been completed to be able to see the chemically processed cine film images. The radiation exposure to patients and staff has been significantly reduced. This is especially important in interventional procedures and electrophysiology and pacemaker procedures which can be lengthy. The Toshiba digital system allowed the imaging sequence and techniques to be customized to provide as nearly optimal images as possible. This was accomplished by using variable width x-ray pulses, different image acquisition rates and different exposure per image techniques which resulted in reduced radiation exposures for different clinical procedures such as electrophysiology and pacemaker procedures. The staff also benefited since the image techniques were customized to the situation and thus reduced accumulative radiation exposure to the professional and support staff. In addition, the need to repeat part or all of a procedure has essentially been eliminated due to the ability to instantaneously verify the location of the interventional device and patient anatomy at any time during the procedure. The computer can process the digital data after acquisition to clarify or enhance a particular area of an image. Digital analysis lends accuracy to selection of angioplasty balloon or stent size. One of the six cardiac catheterization labs is a bi-plane system used primarily when the reduction of contrast media (x-ray dye) is important. Bi- plane cardiac catheterization systems with the ability to obtain images at more complex angles are very important in the treatment of children and infants. They provide bidirectional simultaneous images of the heart, minimizing the amount of contrast media needed. Bi-plane (bidirectional) simultaneous image acquisition is also beneficial for diagnosis and treatment of cardiac arrhythmia where placement of the catheters is difficult as well as critical. All of the single plane cardiac imaging systems use the Toshiba Model CAS-210 image system which allows peripheral vascular and intracranial studies to be performed without repositioning the patient (reversing the position of the patients head and feet on the table) which reduces the procedure time, as well as stress and discomfort to the patient. Using the Toshiba computer controlled digital cardiac imaging systems in the catheterization laboratories has eliminated darkroom support staff, film and chemistry supply costs, film processing costs and film quality control staff costs. This resulted in a savings of over $225,000 in the first year. The utilization of technical support staff has been significantly improved since they are no longer required to be involved in handling cine film and dealing with all of the routine problems associated with cine film imaging. This has allowed the staff to enhance their focus on patient care utilizing the computer controlled digital cardiac imaging systems and archived digital image studies. It is critical to recognize that when the Methodist Heart Center was conceived and developed, there were no digital image related standards and thus it was necessary to establish functional standards as a part of this project. In fact, there remains a lack of adequate comprehensive digital image performance standards for the acquisition, archive and transfer of clinical images in the industry.
Importance At the time of the selection of the system, the Toshiba medical imaging system was the only company capable of delivering a clinical imaging system incorporating the Charged Coupled Device (CCD) camera technology with the 1024 x 1024 matrix. This technology afforded high spatial resolution images which results in improved clinical image quality. The clinical images viewed both in the cath lab and on review stations are typically acquired at 30 images per second with 1024 x 1024 digital image matrix. From the beginning of the Methodist Heart Center project, it was believed that it would be necessary to have a filmless cath lab in the near future if Methodist Heart Center was to be in the forefront of clinical care and to remain there in the future. It was also believed that digital cardiac imaging capabilities would be required to meet the needs of the evolving health care environment. An educational program was developed to prepare the staff for the new technology when it was introduced and completed its objectives simultaneously with the opening of the Methodist Heart Center. After the Toshiba cardiac digital imaging systems were installed, Toshiba s applications specialists were very instrumental in the conversion to cine filmless operation. They provided on-site hands on clinical staff training and worked with the radiologic technologists to develop the appropriate protocols for digital cardiac image acquisition and storage which enabled the cardiologists to complete the procedure and leave the room with the archived digital image study in hand. The staff and physicians were immediately impressed with the user friendliness and ease of operation of the new Toshiba computer controlled digital cardiac imaging systems. It is essential for the medical community to transition to digital film imaging in order to be part of the more global efforts to improve clinical care while reducing the time and costs associated with the delivery of health care providing the highest possible quality patient outcomes.
Originality From the onset of the project, one of the primary objectives for the Heart Center was a commitment to provide the best patient care by acquiring the latest advances in cardiovascular imaging technology. The administration committed to support the Heart Center concept including digital imaging and other advanced and aggressive cardiac care concepts. The primary project team was interdisciplinary; with input from physicians, administration, radiologic technologists (including Ms. Jennie Wright, Technical Supervisor), and industry experienced consultants. This team worked for several months to assemble the necessary design definition and performance criteria for the different aspects of the project, ranging from architectural, structural and product needs. Ultimately, these needs were consolidated into a comprehensive set of performance criteria which could be used for identification and selection of technology and products. Much of the information was developed in close conjunction with the equipment vendors who were able to provide the necessary technology. The team s extensive research included site visits and consultation with users, internal review and analysis of the data acquired and compiled by the team. Information was evaluated and then consolidated into vendor and technology comparative tables and presented to the cardiologists. A comfort level had to be reached about the transition from cine film imaging to a cine filmless technology. A digital solution must provide no degradation in image quality, a decrease in procedure time, and enhanced clinical utility that would result in diagnostic excellence. There were many claims by cardiac digital imaging system manufacturers to provide state-of-the-art digital imaging. However, the system selected was Toshiba, whose image quality, digital acquisition rates, and image storage capacity had been exhaustively evaluated quantitatively. In addition, the systems were superior with respect to the ease of use and clinical versatility.
Success TESTIMONIALS The cardiologists using the digital cardiac imaging systems have seen their actual procedure times diminish with increased stability and reliability. Dr. Robert Wey and Dr. Howard Hurd, Cardiologists of Lubbock, both have repeatedly emphasized the efficiency of the catheterization laboratory design. They both have reported that, "The efficiency and utility of having all of the facilities in one place where the room layouts and imaging systems are identical, having superb image quality and precise quantitative image analysis, have tremendously improved the safety and efficiently of heart procedures. It also is important to appreciate the value of immediately having high resolution hard copy images as well as being afforded the opportunity to record dynamic imaging on VHS tape as desired." Dr. Hurd and Dr. Morgan, Morgan Consulting, Inc., have both elected to have their own interventional cardiac procedures done in these cardiac catheterization laboratories and indicated, "The high performance of the systems was critical to determining what course of treatment to follow and the ability to see the images as they are acquired, preventing delay as well as assuring that the information needed was in the images". The digital imaging systems continue to provide image quality without technological upgrades or subsystem replacements, which is remarkable since the digital imaging system selection was finalized approximately four years ago. Typically, computer based medical imaging systems are obsolesced within three years or less after introduction into the market place. The foresight and credibility of the three individuals involved in the concept and design implementation has been fully vindicated by the continued performance of the Toshiba digital cardiac imaging systems. The excellent performance of these systems is assured through a comprehensive image quality assurance program which includes comprehensive evaluation of the digital imaging systems on a periodic basis. Difficulty
It was absolutely critical to discard the established perspective by previous
experiences of individuals involved in order to see the project from an
essentially unbiased and fresh perspective. It was also critical to establish
the technological capabilities of the digital cardiac imaging systems. There
had been many previously unsuccessful attempts in the industry to use digital
imaging systems in busy, aggressive cardiac care programs. These tasks
included the formidable obstacle of eliminating the cine film in cardiac
imaging since it was a psychological security blanket for many cardiologists
who had used it throughout their clinical careers. |
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