Radiography remains orthopedics’ mainstay, with more than 75 percent of imaging studies still x-ray based. Digital radiography is the flavor of choice in 2008, making good business sense in a digital environment. The combination of remote access to imaging results, better management of large imaging volumes and more accurate patient diagnoses are key selling points for using DR in orthopedic imaging, whether it is in a small community hospital, critical access center, outpatient facility or orthopedic physician practice.
What distinguishes musculoskeletal radiography is the number of specialized views that require special positioning of the patient and the angulation of the x-ray system and the detector. Because the musculoskeletal system is so complex, over time, people have learned that a radiographic projection recording in a particular position will be most important. One key element has been coming up with different ways to mount the system in such a way that it is flexible enough to get these complex views, according to Michael Flynn, PhD, senior staff medical physicist, at the Henry Ford Health System in Detroit.
DR + tomo = more detail
Henry Ford Health System serves Southeast Michigan with seven hospitals, approximately 18,000 employees including 80 radiologists and performs about 1 million procedures per year. The Henry Ford Hospital in Detroit is using the Sonialvision Safire II system from Shimadzu Medical specifically for orthopedic studies.
The Sonialvision Safire II supports general radiography, fluoroscopy, tomography and, in particular, supports tomosynthesis. The clinic uses the system predominantly for musculoskeletal applications. The high resolution of the Selenium direct DR detector records fine bone details. For tomosynthesis, 75 precisely registered views are acquired over a 40 degree arc and reconstructed using specialized software. For a typical joint, this results in a stack of about 75 tomographic images with 1 mm spacing. “Our focus and utilization has been on musculoskeletal joint imaging where we find that it is superior for revealing occult fractures which tend to be subtle and not revealed on general radiographs,” he says.
Why is it superior? The cross-sectional tomographic depiction of the anatomy is important for removing overlying structures that obscure small fractures and for demonstrating high contrast for fracture lines that are rarely aligned optimally for detection with conventional radiographs. “We have done comparisons of this particular tomosynthesis system to studies done with thin 64-slice CT and we do find that the tomosynthesis has about three times as better spatial resolution in plane than CT does,” he notes.
Flynn says the orthopedic specialists routinely use DR with tomosynthesis in cases where the finding is particularly subtle or uncertain, such as suspected hip fractures that present in the ER.
“What we are finding with tomosynthesis is it reveals more directly the fracture line and the extent to which the fracture line might be traversing the bone which will influence the way one manages that patient in terms of surgery or release,” Flynn says.
Specialty views in HD
Orthopaedic Specialists of North County in Oceanside, Calif., a specialty orthopedic group, chose to make the jump from analog to digital x-ray three and a half months ago with the purchase of the Stryker HD DR 3000 powered by Swissray for general orthopedic radiography procedures, according to Lead Technologist Laurie Corning. Last year, the practice provided almost 10,000 imaging studies.
Certain specialized orthopedic views, such as Merchant or Sunrise views, have historically been more easily obtained using CR cassettes than by using DR. With the Swissray system, this is no longer the case. “Special angles or views like Merchant or axillary can be pre-programmed, which is a time-saver for our techs when they are really busy,” she notes. “This is the main reason we chose the system—because of the special auto-positioning settings.”
Previously, for Merchant views, patients had to get up on the table and put their legs through a wooden stand. Now, patients can sit in a chair leaning slightly to the side, so that the x-ray comes across to show the patellas, as opposed to lying down. With the HD post-processing, physicians are given additional features like electronic preoperative planning tools such as implant templating and stitching. An auto-stitching feature creates long films by overlapping of separate images that are seamlessly fused for full leg and spine viewing—all in one exposure. Techs simply set the minimal and maximum height, then hold the button and the system takes over, angling itself to take three images from the plumb line to the crest of the hips.
Prior to DR, a routine L-spine with five views took about 15 minutes. Now, it takes about six minutes. “We acquire images right away, minimizing the risk of patients moving or shifting and almost eliminating repeat imaging,” Corning says.
Maximizing patient throughput
Strong Memorial Hospital Outpatient Orthopedic Clinic, an affiliate of the University of Rochester Medical Center in New York, sees more than 300 patients a day for a wide range of imaging exams from pelvis trauma series to cervical spines, shoulders, hips, knees and extremities. In 2005, the clinic installed the Kodak Directview DR 7500 from Carestream Health in one of the clinic’s eight exam rooms with both a wall stand and table.
Providing 37 physicians and 20 mid-level providers with services in a timely manner can be challenging with such high throughput. Since installing the DR 7500, Supervisor Cindy Redmond (RT) reports seeing improved image quality and reduced patient wait times. “Specialists are able to stay on schedule even during peak periods,” she notes.
For example, if a tech is taking four views of the knee, using CR, it takes approximately one minute per cassette for the image to process. “So you are talking at least four, five or six minutes total compared to taking an image in seven to 10 seconds with DR,” Redmond says. For axillary shoulder images, instead of the patient lying on the table and holding the cassette, the wall bucky is put in the horizontal position and the patient’s arm is stretched over the top.
“You can see the improved image quality in the tubercular patterns when doing extremity work just from the shoulder and knees, which are the high volume we do here,” she says. Techs wait to use the room simply because of the efficiency compared to CR. “The acquisition speed, high-quality images and auto-centering capability all free up time to spend with the patient—this is the room of choice,” Redmond notes.
Sarasota Orthopedic Associates in Sarasota, Fla., went directly from film to DR, choosing IDC’s 2200 dual-detector X-Series and the 1590 X-Series systems. “We needed assurance that image quality would meet our needs,” says Administrator Joyce Sewall. Since four physicians joined the practice, annual imaging procedure volume increased from 3,600 to 5,600. Because of the increased volume, they knew CR would not meet their needs.
X-ray Technologist Donna Hall says it was more advantageous to go with DR because it eliminated the use of cassettes all together. “We are able to view the image in 3 to 5 seconds and make any adjustments, if needed, immediately,” Hall says. “To have images produced without any down time is a huge deal with the high volume of patients we see daily.”
While they have not yet met their return on investment, they will, Sewall says. Paying for a service contract and the cost of film during the transition has been the obstacle to achieving this. “We projected a savings of approximately $8,200 a month and we will definitely clear that,” she says.
Poised for growth
According to market research firm Global Industry Analysts, the world DR market is expected to reach $844.2 million by 2010, growing at a CAGR of 6.88 percent from 2011 to 2015. Fueling this growth is a 50 to 80 percent reduction in patient exposure to radiation, increased patient throughputs, flexibility in image manipulation and accurate image capture. One thing remains clear—DR continues to dominate as a standard of care in health imaging as adoption and utilization increase globally.