Applied Radiology

Dr. Ludomirsky is a Professor of Pediatrics and the Director of Echocardiography, Michigan Congenital Heart Center, University of Michigan, Ann Arbor, MI.

The echocardiographic laboratory at the Michigan Congenital Heart Center is one of the busiest labs among pediatric cardiology divisions in the country. The laboratory is under constant pressure to simultaneously perform multiple studies, as well as to spread its manpower and equipment to other areas in the hospital, including the operating room, catheterization laboratories, fetal center, and the different ICUs. The laboratory performs approximately 8000 studies per year and serves the Michigan Congenital Heart Center. With improvements in technology and the introduction of digital solutions for image manipulation (5 years ago), it was very clear that the only solution to improve and smooth regular laboratory tasks was to convert the laboratory to digital imaging. The conversion was performed in two stages. The final stage was completed 2.5 years ago. During this time, the laboratory has performed approximately 20,000 echocardiography studies and we believe that now is the appropriate time to reflect on the past, evaluate the system (KinetDx, Siemens, Mountain View, CA), and plan for future development.

The first part of the installation included five sonographer stations (with a single monitor in each of the sonographer/imaging rooms) and two workstations (with a dual monitor in a central imaging room where the server was located). A year later, after being acquainted with the system and appreciating the tremendous value of digital imaging, six additional stations were installed each with single monitors in six separate locations: clinic area, patient ward, intensive care unit, library, auditorium, and fetal center. We also added another dual-monitor workstation in the central imaging room. We were concerned that the server would not be able to handle such a major load; but with the appropriate upgrades and enhancements, we didn't experience any deterioration in the system's performance.

Transition to Digital Imaging

What have we learned? The first obstacle we encountered was to convince our sonographers and pediatric cardiology fellows to convert from the habit of taping the whole study to saving short clips. We tried to design specific protocols through which specific clips should be acquired, but after a week we realized that when working with skilled and experienced pediatric sonographers this step is not needed. The learning curve of the sonographers was extremely quick. A detailed study performed at our center of 100 consecutive echocardiographic examinations in neonates and children with congenital heart disease comparing tapes with digital clips didn't show any loss of data or misdiagnosis. ¹

In the following paragraphs, we make suggestions based on our experience of moving to a digital lab, from the perspective of physicians, sonographers, patients, and the administration.

Physicians

The digital laboratory offers physicians several review capabilities that were not feasible using the old tape technology. The physician can review multiple images in real time and can monitor several studies at the same time. The quick feedback can be relayed to the sonographer/pediatric cardiology fellow during the study. The study can be reviewed on the digital monitor in different formats (i.e., full screen or up to 32 small loops in 1 screen). All loops are available to run simultaneously.

The system saves a significant amount of time for the physician. It is easy to review and retrieve any study. The studies can be retrieved either by patient name and/or registration number and will appear on the screen within 4 to 5 seconds. If the studies are not online, but in storage mode, it will require up to 4 minutes to bring up the study. Using this technology eliminates the need to identify a tape and to key the tape to the right spot. Digital technology also eliminates the potential of image degradation.

One of the most used capabilities of this technology is the "compare" option. The physician is able to compare the current study to multiple previous studies. The studies appear in side-by-side mode on one monitor, and on separate monitors in a dual-monitor setting. This modality represents significant improvements in patient management and time savings. For example, in a patient in whom there is the suspicion of endocarditis, a comparison can be made between the current and previous studies to assess the size, location, and mobility of vegetation. Comparison of ventricular function, size of pericardial effusion, transvalvular gradient, etc. is crucial information for the clinician. Recently, a wide calculation package was added to the system. This has enabled the echocardiographer to perform online calculations in the same form it is being done on the echocardiographic equipment.

The system can also be used as a great teaching tool. Different teaching files are created according to different diagnoses. Once a study is marked as high-quality for teaching, there is a possibility to identify and retrieve any studies under specific diagnoses. This is very helpful in the teaching of new fellows, visitors, residents and medical students. Using digital imaging and storage is also helpful to physicians to prepare talks, presentations, and lectures.

Sonographers

The major concern of the sonographers was the psychological fear of converting to a tapeless laboratory. We noticed a relatively short learning curve among our sonographers that ranged between 1 to 2 weeks. Once they were familiar with the digital system, none of the sonographers wanted to go back to the old tape technology. There is no limit to the number of clips that could be acquired. Assessing complex anatomy in congenital heart disease is sometimes challenging and requires long loops. But this has never represented a major obstacle for this technology. We have determined that loops up to 8 seconds long are sufficient to fulfill any requirement from a long sweep. We are currently using a 2-beat or 2-second clips on regular basis. When a long loop is required, it is easy to switch to a 6- to 8-second loop. A major advantage of this system is the capability of the sonographer to receive quick feedback from the physician. Again, there is no need to key a tape to the right spot and observe a 25- to 30-minute study. Loops can be reviewed continuously within a shorter time without losing any accuracy.

Using the system to review and compare studies, the sonographers believe that they are more prepared to assess a child with congenital heart disease. Refreshing of basic anatomy and surgical details will yield a better study in assessing a child with congenital heart disease following intervention. The sonographers find the compare feature is one of the major advantages of this system; it helps in diagnosis, interpretation, and manipulation.

In the pediatric population, complete sedation is used frequently. This provides a window of 20 to 25 minutes to complete the study. If a longer study is needed and/or incomplete sedation is achieved, it can result in an incomplete study. Calculation usually takes a significant amount of time from the actual scanning time. With the availability of the calculation package on the digital system, the imaging part of the study can be completed first and then the sonographer can use the workstation to finalize the calculations as needed. Because of the nature of digital image acquisition there is no degradation of image quality and/or signal to noise ratio. This results in appropriate and very accurate calculations.

Patients

Patients also benefit from the installation of the digital lab in our center. Better communication is established between physicians, patients, and the patients' parents. It is extremely helpful to review the study with the parents and to show them the comparison between the previous and current studies. We were surprised to see the depth of the parents' understanding of their child's disease and their desire to review new data with the physician. Specifically in our fetal center, we found that it is easier and more informative to explain the cardiac defect of the fetus when reviewing fetal images on the workstations.

Administration

Even though the initial investment in digital technology is substantial, it pays back quickly. Savings in physician and sonographer time, increased efficiency, and savings in storage space and tape/VCR cost have easily demonstrated a significant return on our investment within a 2-year period. Since there is no need to store tapes, that space can be used for other needs. As technology improves, the server storage capacity continues to expand, while the cost for the storage unit decreases dramatically. The server can be extended by using DVD technology.

Communication and connections

The digital echocardiography laboratory is not an isolated island within the cardiology service. The ultimate goal is that clinicians will be able to review all imaging modalities on the same workstation using digital technology. Currently, we have installed the capability of reviewing angiograms on our KinetDx system in the same fashion as we review echocardiographic data. In the near future, we hope that digital images from magnetic resonance imaging, computed tomography, X-rays, and nuclear medicine studies will also be incorporated in the system.

There were questions about connectivity between different echo-cardiographic equipment and the KinetDx system. Different digital echocardiographic equipment from Seimens Medical Solutions (Erlangen, Germany), Philips Medical Systems (Bothell, WA), and GE Medical Systems (Waukesha, WI) have been connected to the KinetDx network without problems. Once the images are stored to the KinetDx system server, all manipulations and calculations are available independent of the type of echocardiographic machine used.

The digital system has improved our communication with referring physicians. We have the capability to transfer images via the Web, which allows referring physicians to review the actual studies. This could be used as the next generation of telemedicine and it will help to facilitate second-opinion consultations.

Conclusion

The conversion of the echocardiography laboratory to digital technology was a major milestone. It has made us more efficient and accurate, and we believe that it has improved patient care. We expect the digital lab to become part of a total cardiology solution that will allow us to better serve our patients at the Michigan Congenital Heart Center. *