Digital Radiography - An End to Orthopaedic Practice as We Know It?

From an article in "Orthopaedia" the Vanderbilt University Medical Center Orthopaedic Departmental Newsletter: Spring 1999 by W. Burman, MD.

On March 10, 1999 Edward J. Harvey MD, FRCSC, Assistant Professor of Orthopaedic Surgery at McGill University Medical Center in Montreal, Quebec traveled to Vanderbilt University Medical Center to present a 2 year experience of life without standard xray films in an emerging "filmless" era of computerized xrays.

Dr. Harvey is a highly trained orthopaedic surgeon with residency at McGill University and two fellowships - one in Orthopaedic Trauma at the Harborview Hospital at the University of Washington in Seattle; the other in Hand and Microvascular Surgery with Dr. James Urbaniak at Duke University.

Computerized radiology or "filmless existence" holds great promise for the field of Orthopaedics which has been a "superuser" of radiological services ever since the introduction of orthopaedic radiography by E.A. Codman.

The ability to simultaneously view the same xray image on multiple monitors throughout a networked healthcare enterprise can greatly facilitate the access to and sharing of critical graphical patient information by different services. Longstanding tensions between Orthopaedics and Radiology over the possession of films stand to be defused. Concern about "lost" studies requiring re-radiation of the patient can be diminished. Long term radiological archives can be made resistant to demands of cash-out for silver nitrate or an excessive consumption of physical space. Direct digital radiography can lower radiation doses patients receive on routine studies by a factor of ten. "Poor quality" films can be made acceptable by computerized image manipulation which drastically reduces the need for and expense of "retakes".

Digital Radiography is not new at Vanderbilt University Medical Center. A multi-million dollar digital radiography PACS (PICTURE ARCHIVING and COMMUNICATION SYSTEM) was "rolled out" at Vanderbilt in April of 1998. After only a few short, clinically chaotic months, the system was "rolled up" and the system of standard xray film was restored. However, the same PACS system is scheduled for reintroduction this April.

According to Dr. Harvey, PACS can also mean "Pretty Awful Clinical Scenario".

The transition of Radiology at McGill to a filmless (PACS) PICTURE ARCHIVING and COMMUNICATION SYSTEM was described as a very expensive and frustrating experience persisting over a two to three year period. Like Vanderbilt, the design of the McGill PACS system was undertaken by radiologists and the accountants with little or no input from high volume clinical users such as the Orthopaedic Department.

There is a considerable difference in the xray viewing requirements of a radiologist versus an orthopaedist. A radiologist generally reviews all xray images in the same office within a certain timetable. It is a relatively simple matter to serve the appropriate image in an appropriate time frame to a specific radiologic workstation over a small, high speed network .

Orthopaedists must be prepared to quickly review radiographs and derive treatment plans in a wide variety of geographically distinct locations (Clinic, Office, OR, ER, Wards, etc.). Properly serving an orthopaedist's need to view critical graphical data in such environs is highly complex and expensive. The radiologic image files are usually at least 10 megabytes which can translate to an excessive wait (2-3 minutes over a standard hospital network for a single xray) during a busy clinic session. Widespread distribution of high speed, fiber optic cabling is prohibitively expensive. Space, funding and training for the use of complex radiologic $35K- 60K workstations in cramped clinic quarters may not be available. These factors cause serious disruption of the orthopaedic work flow and create a queue for a remote and unwieldy, sequential (versus simultaneous) image-viewing computer workstation.

Dr. Kenneth Johnson related significant problems in the operating room during the short-lived PACS introduction at Vanderbilt with inadequate facilities for the intraoperative viewing of digital xrays. A work around which involved the use of plain paper printing of xray images lead to problems with filing, scaling and inadequate image illumination.

Despite the great potential of PACS (after substantial investment), a distinct possibility exists of less access to and less optimal viewing of xrays - the lingua franca of Orthopaedic practice. Any number of unfavorable scenarios can result including the placement of a family of a patient on a queue with their surgeon to receive an encumbered and public explanation of their relative's need for surgery in an overcrowded physician's clinic work area.

Dr. Harvey emphasized the urgent need for the Orthopaedic Department to articulate to the planners and executors of PACS the functional requirements of orthopaedic practice.

"The orthopaedic surgeons must dictate what they need 100% of the time in what time period for which patients; where the output has to go and how fast the turn-around has to be. If these terms cannot be met, then the use of traditional xray film must be continued.

Specifically, walk-in patients must have imaging in "x" minutes which must be sent to sites "A,B,C " in "y" amount of minutes. Any archived images have to be downloaded in "z" amount of minutes.

When the new system is ready, a test of a single workstation should be validated by a quality assurance mechanism. Thereafter, a similar QA network testing of throughput should also be successfully undertaken for a designated period of time before hard copy (xray film) is safely abolished."

Although difficulties persist at McGill several years after the introduction of the Radiology PACS, the stricture of image access has been somewhat relieved by the Orthopaedic Department establishing their own image server. A dedicated departmental image server avoids being caught in a bandwidth bottleneck frequently encountered when joining in the throng of other departmental requests to the Radiology PACS server. At night, the Radiology department uploads all musculoskeletal films onto the Orthopaedic Departmental server. During peak demand of the day, orthopaedic clinic and office terminals fitted with the image viewing software pull the musculoskeletal images from this dedicated orthopaedic image server.

Besides decentralizing the PACS archive, a big question needs to be answered. What is the minimal acceptable resolution required for the practice of Orthopaedic Surgery? Dr. Douglas Lundy, a trauma fellow with the VUMC Department of Orthopaedics is undertaking a study to see if standard medium to low-end digital cameras and flatbed scanners can adequately detect subtle radiographic findings such as those yielded by undisplaced fractures of the femoral neck, carpal navicular and odontoid process.

Compression of digital images from larger (10 megabytes) to smaller (1-200 kilobytes) file sizes has far-reaching technical and fiscal implications. Smaller file sizes can travel rapidly over standard networks, require much less expensive archival hardware and can be displayed on standard, ubiquitous PC workstations. The trade-off for image compression is generally a loss of high definition.

Dr. Harvey states there must be the availability of lossless compression. Lossless compression does reduce file size (2:1 or 3:1) but this is insufficient to obviate the need for high speed networks and expensive image viewing workstations.

Even with "optimal" images (2kx2k, recommended by ACR-NEMA for the DICOM 3 standard of diagnostic quality), musculoskeletal radiologists from Harborview missed subtle fractures which they were able to detect on conventional films (Wilson, Hodge, Radiology, August 1995, 196: 565).

A major distinction of Orthopaedic from Radiologic practice is that there is a direct opportunity to combine history and clinical exam with xray evaluation. Clinical information such as snuff box tenderness may be more sensitive to the presence of navicular fracture than even the highest resolution study. An insistence for the highest possible resolution for all orthopaedic xray evaluations will technically and fiscally limit the availability of these studies. Under such circumstances, the usual preference has been clearly stated by Dr. Clement J. MacDonald an internist and informatician at the Regenstrief Clinic in Indiannapolis :

"I'd rather be missing a few pixels than see no pixels."

In "MD Computing - 9:350 1992" Clement MacDonald continues:

"I could detect no difference between the original film and an image decompressed from a 60:1 JPEG decompression. But I should point out, I am only an internist. Radiologists "easily" saw the difference between the 60:1 compression and the original. But why waste channel time sending more information to an internist than he or she can make out?"

Dr. Harvey has indicated that life after PACS can be far from utopian. Will long queues of frustrated orthopedists before expensive and complex radiologic workstations resemble those before ATM machines on Friday after 5 PM prior to a holiday weekend? It appears there may be a chance that well conceived and articulated Orthopaedic plans for the deployment of an orthopaedic system of digital radiography may avert "Pretty Awful Clinical Scenarios" and deliver the full promise and potential of PACS.