Digital imaging affords major efficiency gains

Reorganization and use of direct radiography speed patient flow and increase department productivity

BY DEAN R. DEMASTER, MBA, AND MICHAEL J. SHORTSLEEVE, M.D.

Radiology administrator Dean DeMaster and radiologist Michael Shortsleeve discuss a digital radiograph. Soft-copy images from more than 40,000 general radiography and portable x-ray exams are read annually at Mount Auburn Hospital in Cambridge, MA.

Ever since PACS technology came into focus, the development of filmless, electronic imaging departments has been the subject of widespread speculation. At Mount Auburn Hospital in Cambridge, MA, we have followed not only the progress of PACS, but also the revolution in digital imaging.

Mount Auburn is a community/teaching hospital affiliated with Harvard Medical School. Its staff of 500 physicians cares for about 11,000 inpatients and 255,000 outpatients annually, providing specialized care in areas such as cardiology, cardiac surgery, oncology, orthopedics, interventional radiology, endovascular stent grafts, and vascular surgery.

Several years ago, we began plans to rebuild the radiology department as part of a major hospital renovation. As we looked ahead, we realized that the imaging landscape was changing, and our renovation plan became a map to guide us toward electronic image management for the department.

The radiology department at Mount Auburn, with a staff of 19 radiologists and residents and 50 technologists, performs more than 90,000 exams annually. About 44,000 exams are performed in general radiographic rooms or on portable machines. Of these, 40,600 are acquired in digital format and read as soft-copy images on high-resolution monitors.

JOURNEY BEGINS

In 1996, plans in progress for a major hospital renovation included decentralizing significant portions of radiology services. Plans indicated three new radiographic rooms: two in the emergency room and another in the new ambulatory care center located one floor above the radiology department. A computed radiography (CR) reader was planned for each area. The new rooms would replace two conventional radiographic rooms and a chest system. They would handle more than 90% of our diagnostic x-ray workload. No darkrooms were included in the plans.

After observing a new flat-panel digital radiography system at the 1996 RSNA meeting, however, radiology plans were put on hold until we could evaluate this new technology. This exploration marked the real beginning of our journey to direct digital radiography (DR) and electronic image acquisition and management.

The renovation caused us to take a nontraditional approach, in which acquisition of digital x-rays with soft-copy interpretation preceded the installation of a PACS. Our x-rays would be read from monitors, while CT, MRI, and ultrasound were still being read from laser film. All exams would be archived on film, and PACS implementation would follow completion of the renovation.

The first step along this path was to weigh the productivity advantages of DR against the risks of designing around a new technology that was not yet commercially available. Productivity was particularly important because technologists would be working in the new rooms without radiology support personnel. Workflow would depend on minimizing their nonimaging time.

We also had to consider present versus future costs, knowing that it would be difficult to fund a conversion to DR once CR systems were installed. In a nutshell, our decision was to go from conventional radiography to direct digital acquisition, omitting CR except for one reader for portable exams.

A key factor in our willingness to accept risk was our timeline. The first room would not be needed until December 1998, and the others would follow in September and December 1999. The timeline would allow considerable flexibility if equipment deliveries fell behind schedule. Two existing radiographic rooms would not be demolished until August 1999, and a third would remain untouched.

The second step was establishment of three work groups to plan equipment, space, and workflow. We enlisted the help of a key administrator, the vice president for administrative and clinical services, who was responsible for the radiology department as well as the hospital renovation project. The materials management director also became part of our equipment selection team. Throughout the project, team members met with vendors, accompanied us on site visits, and attended RSNA meetings in 1997 and 1998.

The third step was evaluation of the emerging digital technologies. Our research led us to believe that flat-panel detectors would offer higher resolution than charge-coupled devices and that systems using amorphous selenium detectors offered the best solution and were closer to commercialization. We determined that DirectRay technology from Hologic's Direct Radiography Corp. would provide the necessary efficiency and quality.

INSTALLATION PATH

Ultimately, the systems we wanted were not available within our timeline. Instead, the manufacturer installed a retrofit version of the DirectRay system in the ambulatory care area. The system utilized a 90º tilt table to permit upright exams as well as table work. In the ER, we installed Philips digital-ready x-ray systems and an Agfa CR reader, with plans to upgrade both rooms to DR when digital detectors became available. We used our contingency plan of imaging outpatients in the main department for nine months since ambulatory care opened before the retrofit system was installed.

The manufacturer encountered a series of problems modifying conventional components of the x-ray equipment. Once these were corrected, start-up of the DR system was relatively easy. It consisted of extended applications training over a period of several weeks, entry of our department routine views into the exam menus on the system, and fine-tuning of image displays.

During the 12 months since we installed the DirectRay system, we have used it for more than 7500 exams. The productivity advantage over our screen-film and CR systems has been greater than we anticipated: Image quality has been excellent, physician acceptance was rapid, and no detector-related downtime occurred. A routine day in the DirectRay room averages 35 exams; busy days exceed 50 exams. The immediate feedback from this system provides the opportunity for more expedient patient flow and fewer repeat exams.

Our initial hypothesis on the difference in productivity between DR and CR is proving true. We achieve substantially better productivity using our DR system. We've done an initial time/motion study comparing 75 consecutive exams done on each system. These results show an overall productivity advantage of three to one for DR. For a PA & lateral chest study, the difference is four to one.

Even more striking is the difference in the time our technologists spend manipulating the two systems, independent of time spent positioning patients and taking x-rays. With DR, they spend an average of 50 seconds per study entering patient data, setting up the study, and sending the finished images to review stations and printers. With CR, they average eight minutes per exam on these functions. The time interval from completion of the last exposure to the arrival of the completed study on the monitors averaged 16 seconds for DR compared with almost six minutes for CR.

Healthcare continues to experience shrinking resources. Cuts in hospital reimbursement and the resulting decrease in capital funds have slowed our plans for PACS installation. The current technologist shortage presents an ongoing problem. We believe that the productivity advantages of direct digital radiography will play a critical role in meeting these challenges.