Applied Radiology

Ms. Beird is the PACS System Administrator of Ann Arbor VA Healthcare System, Ann Arbor, MI.

E veryone in the industry is talking about picture archiving and communication systems (PACS)--how to design a system, the challenges of implementation, and the impact digital imaging can have on patient care. At Ann Arbor VA Healthcare System, when we talk about PACS we speak from experience. Our PACS integrates all modalities into a 100% digital environment that streamlines workflow, reduces operating expenses, and improves patient care.

Current and prior imaging studies are available consistently for interpretation or review. We have eliminated lost or missing films. More importantly, Dr. Charles Marn, Chief of Radiology Services, reports that timely access to a patient's previous studies (from any modality) improves the quality of diagnostic results we provide.

Our 147-bed facility provides ambulatory and tertiary services for veterans in the Southeast Michigan area and is a teaching hospital affiliated with the University of Michigan.

The hospital began with mini-PACS, which included a 0.5 terabyte archive and two primary diagnostic work-stations, and a teleradiology system that connected the main facility with an outpatient clinic in Toledo, Ohio. In 1997, we began to upgrade to a full-scale PACS.

All imaging modalities were connected to the PACS by 1998, and the hospital significantly reduced expenses for film and chemicals from $125,145 in fiscal year 1996 to $20,419 in fiscal year 1999 (Table 1). Labor costs have been trimmed by $26,300 a year. Because we are a teaching hospital, our percentage of missing films is high--between 15% to 20%. Therefore, digital imaging has also eliminated the cost of labor and consumables for retakes. At the same time, workflow is improved. Imaging studies are now available in just minutes to referring physicians on any floor of the hospital. With the film-based system, it might take 2 to 6 hours for a referring physician to see a film study.

Digital imaging has also improved technologist productivity and patient throughput. It may also improve the quality of care we are able to provide. Currently, we are conducting a study that compares how many previous studies a radiologist examines with a film system as compared with a digital imaging system. We are also tracking how long it takes for radiology reports to be made available, for technologists to process studies, and for patients to complete their exam.

Needs assessment

Prior to interviewing any vendors, we created a multi-disciplinary committee to develop a list of requirements. This step was critical to our success, because it established goals and objectives that drove the selection and implementation of the final, full-scale PACS solution.

Our PACS team consisted of the chief of radiology, a hospital administrator, the chief technologist, and a referring clinician. The chief of radiology and the chief information officer had the foresight to recognize the importance of a dedicated, full-time system administrator. Thus, I was transferred from the IT staff to facilitate the PACS team.

We developed our PACS team in 1996 and spent 4 to 5 months outlining our goals. During that time, each department representative collected input from, and reported to, a group of his or her peers. All team members agreed on the overall objectives for PACS and participated in creating a detailed system plan and installation guide.

Implementation

Based on the initial needs assessment, I created a detailed request for proposal. After interviewing several vendors, Cemax-Icon, a Kodak Company, best met our list of requirements, which included: functionality of the diagnostic workstation; enterprise-wide networking expertise; archive storage and database technology; teleradiology experience; and validation and integration of imaging modalities.

With the vendor selected, we began to implement PACS. This gradual implementation was desirable because of management and training issues, as well as financial concerns. In our case, this timeline was controlled tightly because of a new construction project. The PACS was cost-justified as part of a $70 million clinical addition, which features a new radiology department, ambulatory care center, diagnostic imaging service, operating rooms, and intensive care units.

In January 1997, our first phase began when we brought the portable CR system and two ICU referral-quality workstations online. In the next stage, which began in May 1997, we integrated ultrasound and RF systems. In June 1998, we integrated CT and MR systems as part of phase three. Phase four, in October 1998, involved connecting angiography suites, a digital chest unit, and general radiographic rooms to the PACS and coincided with our move to a new facility. This stage completed our conversion to digital imaging and now all images are read with on-screen digital display.

Our current stage, phase five, involves establishing worklist management on all modalitites except angiography (completed); and providing remote access to images and the electronic medical record over the Internet (currently being tested). Figure 1 illustrates the PACS workflow for radiology.

Validation process

Each imaging modality was validated before it was brought online. In 1997, Cemax-Icon had a DICOM validation group that was responsible for validating the clinical and technical functionality of its system with leading imaging modalities. This group established protocols and used phantoms to create a series of images that were analyzed for integrity during capture, viewing, and storage. They compared softcopy images with film output to ensure that the images were identical and to verify that positional markers and other critical elements were correct.

Most of our imaging systems had already been validated, with the exception of our new MR and RF units. The DICOM validation group provided a phantom and a series of imaging protocols and we acquired the test images, which were then evaluated.

This validation effort was critical to ensuring the clinical accuracy of all images, as well as the smooth integration of each imaging modality. It also allowed any non-conformance issues
to be addressed prior to linking the modality to the PACS network--which ensured the integrity of every patient study in the archive.

Storage and networking issues

In 1997, we moved our existing image files from our initial archive to our new 17.5 terabyte digital linear tape (DLT) archive. At this time, we began to take full advantage of the workflow benefits of our new large-scale digital archiving system.

Film studies that are necessary for comparative purposes are being digitized as needed, however we are not converting our entire film library. Previous research has shown that film studies are rarely accessed after 18 to 24 months. At our current volume of 60,000 studies per year, we estimate our archive requirements to be 1 to 2 tera-bytes a year in storage. Newer tech-nologies, such as spiral CT, and the increased demand to provide primary diagnostic services to remote facilities will expand our storage needs, so we have built scalability into our system.

Our storage system supports hierarchical storage management and an object-oriented database to speed retrieval times. In our system, the patient is the object. We can enter a patient ID or Social Security number and rapidly locate every study and report for that patient.

We have recently added Modality Worklist, which eliminates the need for technicians to key a patient's name and other demographic information. With this feature, patient demographics are linked to imaging studies through a HIS/RIS (hospital/radiology information system) gateway. For example, a CR system operator can access a list of all scheduled studies for a given day and click on a patient's name, then all of the patient's demographic information is attached to the image and transmitted to the PACS. This workflow enhancement improves full-time equivalent productivity and significantly reduces manual archiving reconciliations.

A bi-directional interface between the PACS and HIS/RIS system enables radiology reports to be accessed from any PACS workstation throughout the hospital. This interface also transmits study schedules to the archive, where previous studies are pre-fetched and posted to the primary diagnostic workstation for comparison with the new study.

Human factors

In any major system conversion, human factors must be considered. For example, we tailored our training efforts to the needs of each audience and described how each staff member would benefit from the PACS. We explained to physicians and nurses in ER and ICU, for example, that the new PACS would provide faster access to images and eliminate lost or missing films. We emphasized to all audiences that the primary purpose of our PACS is to achieve improved access for medical staff and optimized care for patients.

We also stated that we were not going to run parallel systems. Once training was completed and the modality was brought online, everyone would be required to use the new system as it was intended. There is little motivation to learn a new system if you know the old system is still going to be accessible. So it is important to notify everyone up front that they will be required to convert to the new system.

It is helpful to identify a "champion" within each group that has a good understanding of the system and can help encourage and train others on an informal basis. If users are enthusiastic, they will quickly overcome the initial discomfort that accompanies the adoption of a new technology, which will speed learning and create proficiency.

Advantages for radiologists

By far the most important achievement of our PACS is that any image from any modality can be retrieved from any diagnostic workstation in seconds. Dr. Marn and other radiologists report that access to comparative information can influence a diagnosis. Because the PACS is connected to HIS/RIS, patients' previous studies of the same or multiple modalities will be pre-fetched automatically and packaged with current studies. Images are also available on an ad hoc basis. If a radiologist sees a suspicious nodule at the bottom of the lung, he or she can immediately request the patient's most recent chest radiograph.

Dr. Marn outlines additional advantages our PACS offers radiologists: 1) customizable options allow radiologists to create parameters they find most productive for viewing different types of studies. A radiologist can create automatic instructions for the system to retrieve a chest CT with every thoracic spine MR exam, and create hanging protocols that direct the order and location for the placement of each study and image; 2) digital enhancement tools enable radiologists to adjust contrast, enlarge selected areas, and use other viewing techniques to check subtleties in an image. In addition, on-screen measuring tools are so precise that Dr. Marn notes he now includes more measurements in reports; and 3) the use of "bookmarks" allows radiologists to save their place when interrupted for STAT reads, which saves time and reduces frustration. This is also a valuable teaching tool that allows radiologists to share research and teaching cases in an extremely intuitive format.

Future plans

In addition to implementing digital imaging, we have also replaced paper patient records with electronic medical records. Our goal is to make reports and images available to remote clinics and physicians' offices and homes by using the Internet and an interface to electronic medical records.

Enterprise-wide distribution will bring us closer to our referring physicians, while equipping them with diagnostic information they need. That is what PACS is really about--better patient care. AR