Both the art and the science of echocardiography have made tremendous strides in the 50 years since their earliest origins. In its modern-day form, echocardiography maintains a legacy of bedside utility while adopting many of the technologic advances ushered in by the digital era. As a result, it boasts a broad and growing spectrum of application including routine use in primary cardiac diagnosis and screening, therapeutic assessment, and guidance of interventional and surgical procedures.
Propelled by continued advances in ultrasound technology and ever-expanding clinical applications, there is on-going growth in the demand for echocardiographic services. Perhaps the greatest testament to this phenomenon is the fact that, in the US, the echocardiogram is the second most frequently ordered test in cardiology behind the electrocardiogram (ECG). This increased demand has been fueled by more widespread availability of echocardiographic services. In-patient echo-cardiography is no longer limited to larger institutions, and has become usual in most small community hospitals. Out-patient echocardiography, once a bastion of hospital cardiology and radiology departments, has increasingly become an office-based examination. Finally, mobile services and remote interpretation of images have extended the practical reach of echocardiography across the face of the planet, and even as far as outer space, as demonstrated by the recent use of tele-echocardiography aboard the International Space Station.
However, with rising demand for services and with growing expectations of more readily available clinical information, the deficiencies of older echocardiographic systems and archaic workflow methodology have become increasingly apparent. Technologic improvements in ultrasound equipment can help overcome technical limitations of echocardiographic examinations, but this alone is not sufficient to advance standards of efficiency in the review of studies or the communication of results. Only with revised paradigms of image and information management can the cardiology community adequately meet this challenge.
The evolution of digital image and information management offers all the necessary elements required to advance the efficiency and effectiveness of traditional echocardiographic services. Digital recording and archival of images, computerized enhancements of interpretation and reporting, and online availability of patient demographics and study data each help to overcome specific workflow limitations of analog imaging and conventional paper-based processing of information. When employed in concert, these advances contribute to an integrated system that is arguably more powerful and cost-effective than the sum of its parts.
Background and Current Status of Workflow in Echocardiography
The earliest clinically useful echocardiographic images involved a generation of transient oscilloscopic waveforms (A-mode) with review and storage restricted to photographic reproductions of the oscilloscope screen. With the development of M-mode imaging came ink-based strip recorders, permitting review, and paper-based archival of spatial-temporal images. The introduction of two-dimensional (2-D) echocardiography was also accompanied by the adoption of a new medium for image review and storage - videotape. Following the introduction of the first commercially available video-cassette recorders (VCRs) in the mid 1970s, this recording method quickly became a durable standard in echocardiography that remains in use by most hospitals and cardiology practices today.
Current digital image management has its origins in early stand-alone computer systems that grabbed realtime image frames from the echo machine for off-line review or created digitized reproductions from videotape. In contrast to videotape, digitized review made it possible to perform on-screen quantitative analysis, and permitted review of images in side-by-side format to highlight significant serial changes. The benefits of routine side-by-side comparison are best seen in stress echocardiography, where simultaneous presentation of resting and stress images improves diagnostic sensitivity and efficiency of review. However, videotape and digitized imaging share a common weakness. Conversion of realtime digital data to a stored analog signal results in inevitable distortion and degradation of captured images. Playback from videotape compounds the loss of original image quality even further. In contrast, direct transfer of image data to a digital storage medium preserves the integrity of the originally acquired images and ensures high-quality digital review. With further developments in computerized storage, the addition of on-board systems for capture and permanent storage of digital images has become the standard for newer generation echo machines, thus providing a revolutionary alternative to the decades-old convention of video-cassette recording, review, and archival.
Management of patient demographic information and interpretive reports has, likewise, undergone an evolution that parallels the quantum changes in echocardiographic image management. The transition from handwritten, typewritten, and exclusively paper-based record-keeping to networked arrangements that co-ordinate demographic entry, and report generation and dissemination of interpretations to online electronic medical records has revolutionized this entire process. In place of delayed and exclusive access to published echocardiographic interpretations, there is now the prospect of prompt and universal availability of online reports and images.
Workflow Optimization - A Comparative Review of Old and New Methods
Image Acquisition and Review
In reality, digital imaging offers little, if any, advantage of efficiency over videotape during the actual recording of study images. However, the shortcomings of videotaped studies become readily apparent the moment the examination is complete.
- The videotape is removed from the echo machine and bundled with a worksheet.
- It is hand-carried to wherever it will be reviewed.
- The tape is queued to the beginning of the study.
- Prior videotaped studies for the same patient are retrieved and queued for comparative review.
- Once all this is completed, the reading physician undertakes a linear review of between five and 20 minutes of videotaped images, with equivalent time taken to review any available prior videotaped studies.
By contrast, a digital echo system composed of an echo machine, a review station, an image server, and online image archival offers the following scenario.
- The study, with all demographics and measurements, is transferred to an online server when the examination is closed on the echo machine.
- The server automatically retrieves prior echocardiograms for the same patient from the digital archive.
- The completed study is available promptly for review on a remote workstation.
- As opposed to linear review, random access permits the reading physician to review the study selectively or in its entirety, and to easily recall prior serial studies for side-by-side comparison with the current study images.
- Meanwhile, the echo technician is already well underway with the next scheduled examination, no longer burdened by all of the post-examination tasks typically associated with videotape review.
On top of this, digital imaging offers the unique opportunity for remote image review. Either through direct online access to an image server in a hospital or medical practice, or via an offsite secure Web server, it is now possible to perform primary review and interpretation of echocardiographic studies from virtually anywhere in the world. This has immense implications, including access to the greater expertise or efficiency of remote echocardiographers, facilitation of round-the-clock interpretive services, and the potential for improved turnaround of unread studies through more convenient access for reading physicians.
It is difficult to compete with the realtime efficiency of traditional telephone dictation. Even with the most elegant digital review and reporting packages, there remains no question that a physician can verbally dictate a report more quickly than it can be directly transcribed. However, it is the downstream accumulation of strengths and advantages resulting from direct, online report generation that ultimately outweigh the simple benefit of time-saving associated with telephone dictation. As with the previous example of image acquisition, the efficiency of report generation is best examined by looking at the different processes following the action of interpretation. Dictated reports enter a pool of other dictations awaiting transcription, with delays in the availability of a viewable document as long as several days. While the reviewing physician knows the results of the study, no-one else has access to the formal interpretation until the transcribed dictation is made available, often resulting in delayed patient care and suspended clinical decisions. Ôûá