March 2011

Technology Update: C-Arm
By Dan Harvey
Radiology Today
Vol. 12 No. 3 P. 18

Advancements in C-arm technology have been minimal in the past year. After all, engineers can come up with innovations only so fast, and this area of radiology witnessed rapid development in the two previous years. Incremental modifications have been made in existing technology, including systems to reduce radiation dose to both the patient and the user.

The industry is experiencing greater use of flat-panel detectors, which are steadily replacing image intensifiers on mobile C-arms. While image intensifiers will remain available, the shift to flat-panel detectors is clear, says Mark Manum, director of surgery marketing for Philips Healthcare. “We see a shift in demand. More and more, mobile C-arm users are making the change to flat-detector technology,” he says. “We still offer image intensifiers, but we feel the future is limited. Many customers are now willing to pay a little bit more for a better product. Further, Philips is not the only one involved in this transition, so are several of our competitors.”

The reason for the shift is crystal clear: Flat-panel technology provides better image quality, and the newest models have become more reliable because they have less chance of overheating, which can result in shutdowns during procedures.

SmartVascular Software
While Ziehm usually ends up last on alphabetical lists of C-arm suppliers, it was the first company to bring flat-panel detectors into this imaging area. Specializing in mobile C-arm technology for nearly 40 years, it has introduced new products such as the compact Solo C-arm that produces high-quality images while requiring minimal operating room space. And the Ziehm Vision RFD, the company’s mobile interventional suite, was the first mobile C-arm to be used in hybrid room applications.

But Greg Jett, Ziehm’s marketing manager for the Americas, says the company’s most recent innovation is a new software interface called SmartVascular, a solution designed to simplify vascular surgery and produce results in only a few steps. “The software is revolutionary. It operates like an iPad,” Jett says.

The software introduces new workflow designed to produce fast results, raise efficiency levels, eliminate interim C-arm operating steps, and automate imaging processes. SmartVascular is compatible with all Ziehm Vision C-arms and tailored to vascular procedures.

SmartVascular software is compatible with Ziehm’s Vision C-arm portfolio. Equipped with Ziehm’s latest flat-panel detector technology it delivers distortion-free images and a wider field of view and is particularly suited to vascular surgery. Its square, 30-cm X 30-cm flat-panel detector increases the field of view to 2.5 times that of conventional devices, enabling even peripheral vessels to be easily visualized. According to the company, with a 20-kW generator, the C-arm produces high-contrast images of even fine vascular structures with more than 16,000 shades of gray.

The software solution enables vascular surgeons to quickly postprocess x-ray images that support decision making. Surgeons can use the software to create digital subtraction angiography at any time during an operation without using the touch screen as an interface. SmartVascular automates all MSA (maximum opacification sequence) and RSA (roentgen stereophotogrammetric analysis) process steps, allowing complex vascular procedures to be planned and performed with minimum amounts of contrast media and shorter fluoroscopy times.

“Surgery never has to be disrupted,” adds Jett. “C-arms have a workstation, and surgeons engage the workstation. Typically, adjustments must be made at the workstation, but you have to turn the C-arm away from the surgeon. That’s not the case with our C-arms. We offer a total on-board control system. It works like an iPad. The technologist can take the image and rotate it with their finger. They can make the image larger; they collimate the image. It’s a unique process for doing procedures.”

Meanwhile, Ziehm is working on other software innovations, according to Jett. “Through the next two years, we will be working with product development teams on the orthopedic and cardiovascular markets and applications. We’re seeking to push the boundaries for 3D high-speed vascular image acquisition,” he says.

Philips Healthcare
New DoseAware Integration
Philips is another flat-panel C-arm pioneer. Its Veradius x-ray system utilizes a flat-panel rather than the conventional image intensifier, which had been state of the art in interventional radiology and cath labs for about 10 years. “But its deployment is no longer restricted to interventional radiologists and cardiovascular surgeons,” says Manum.

Veradius frees up space in the operating room setting and, most importantly, offers a higher dynamic range, better image contrast and resolution, and less distortion, according to the company. “Surgeons need to have the most accurate portrayal of anatomy, as the image on the C-arm guides the procedure. Decreasing distortion supports improved diagnosis and treatment,” says Manum.

The system can be used for a wide range of procedures, including abdominal aortic aneurysm repair, coronary angiography, orthopedic procedures, and neurologic stimulation.

Flat-panel detectors have improved patient and user safety in terms of dose, but Philips wants to reduce dose even further.
“In our Allura platform, we’ve integrated a product called DoseAware, which allows for real-time information about the radiation dose received. We’re taking steps to couple that technology with our C-arms,” says Manum. “One of the challenges for users is the film badge that provides information on a monthly basis on how much dose they received. But that means they have a month’s work behind them, and they don’t know what exactly might have caused dose to spike. Was it because they were doing more procedures? Were they too close to the source? DoseAware will enable [physicians and technologists] to modify their actions on an immediate and ongoing basis.”

GE Healthcare
Versatile Endovascular System
GE Healthcare’s OEC 9900 Elite allows surgeons to obtain sharp images in the most complex endovascular cases. The Mobile OEC Hybrid OR solution provides superior C-arm and multimodality images viewable in a comfortable and convenient fashion. “Our solution also includes the NuBOOM visualization system that puts as many high-quality, multimodality images as needed in front of the surgeon,” says Elizabeth Usher, chief marketing officer for GE Healthcare’s surgery group.

The GE system uses an image intensifier rather than a flat-panel detector, which GE says performs better in some situations.

“Our research shows that for a flat panel detector to perform as well as our OEC 9900 Elite I.I, power must be greatly boosted and cooling must be increased,” Usher says. “Based on our studies, today’s flat panel detectors, as available on a few models of mobile C-arms, can produce very nice images in smaller anatomy and during short procedures, however they don’t perform as well as the 9900 when used for dense anatomy or during complex surgical procedures.”

The OEC 9900 Elite digital mobile imaging system deploys dynamic range management (DRM) to combine various image algorithms to optimize fluoroscopic images. “An incoming image is divided into six different subimages during image processing,” Usher explains. “Each subimage contains different anatomical information. Rather than processing the entire image at once, each anatomical subimage is processed separately for optimum brightness, contrast, and enhancement levels. After processing, all subimages recombined to create the final image. As a result, the 9900 Elite DRM capabilities process both lower- and higher-density regions of the anatomical structure effectively and display clear images of bones and tissues in a single view.”

The system’s DRM image processing capability enables no-mask motion-tolerant subtraction, an imaging feature than enables users to perform digital subtraction angiography (DSA) without a mask image. “This allows DSA imaging while moving the C-arm or the patient. Preset imaging profiles automatically adjust to highlight the anatomy of interest,” says Usher. “Moreover, our SmartView pivot joint helps with better positioning by making the C-arm easier to place. The motorized option allows surgeons to control the C-arm movements and obtain images from a tableside control.”
Background anatomy is attenuated, and contrast-filled vessels are enhanced. Users can create imagery similar to DSA images in motion, saving the number of runs, contrast injection, and potential radiation dose.

The exclusive SmartView pivot joint allows for a freer range of motion to help correctly position the C-arm. “Better positioning reduces dose and improves procedural workflow because it eliminates the need for additional images,” says Usher.

The OEC 9900 Elite MD is the only mobile C-arm that offers remote user interface, allowing surgeons to control the C-arm from a tableside panel.

“The mobile C-arm enables minimally invasive surgery, which surgeons strive for,” says Usher. “We’ve seen an increase in new procedures such as the anterior hip replacement approach, which require smaller incisions and can greatly reduce both hospital stay and recovery time.”

Offers Floor-Mounted Alternative
Toshiba remains focused on the C-arm mechanical design. “Our concentration involved C-arm mechanics and that enabled us to come out with the five-axis positioner several years ago, a floor-mounted system,” says Allan Berthe, Toshiba’s cardiology product manager for its x-ray business unit. “Typically, most clinicians lean toward a ceiling-mounted system. We offer that and it has unique benefits, but a five-axis, floor-positioned system offers a lot more as far as patient access and coverage. Customers truly appreciate the engineering. When clients have a choice, they’re going with the five-axis product.”

The five-access positioner system offers motions that no other system can provide, according to Berthe. “Other systems can be applied to procedures but not with as much ease for the clinician or comfort for the patient,” he says. “Often clinicians need to move the patient or the table, but our C-arms are out of the way but still right where you need them. Not a lot of manipulation is required. We can easily move the C-arm to gain better access to the patient.”

Berthe says Toshiba is looking to develop a flat-panel system with a detector sized for physicians focusing on cardiovascular work.

“We’re looking at the cardiac space and in the hybrid market, which is an emergent market, where there is a need for a cardiovascular panel size for those doing a mix of cardiac and vascular,” he says.

As such, Toshiba is in the process of adding to its product family a ceiling-mounted system with a 12 X 12 detector that can be combined with the company’s tilt cradle table and even third-party tables that will result in an advanced hybrid system.

“Look for that in about spring 2011,” he says. “We are also going to make a push to show how our five-axis positioner is radial friendly and ideal for the cardiac segment. And that involves not just the C-arm but also a combination of components we designed. But the C-arm remains the key, with its flexibility and maneuverability, enabling users to move the monitors anywhere they want.”

— Dan Harvey is a freelance writer based in Wilmington, Del. He is a frequent contributor to Radiology Today.