Fresh applications indicate impending acceptance of 3D

CAD and virtual colonoscopy pace new developments

Faster, less-expensive, and easier-to-use workstations are paving the way for adoption of 3D imaging. But it's not just 3D driving acceptance of these postprocessing workstations. Radiologists are struggling to cope with the rapidly expanding volume of data being acquired by the newest MR and CT scanners. The next stage of this development may be computer-assisted diagnosis, embraced in an attempt to make sense of the torrent of data. In the meantime, dynamic 3D reconstructions, particularly virtual colonoscopy, set the stage for 3D's widening appeal.

CAD technology is opening another road to 3D acceptance. Integrated with 3D postprocessing algorithms, CAD promises to help detect clinically significant abnormalities in chest CT studies, particularly volumetric studies acquired with multidetector CT. Developments by TeraRecon may foretell how this partnership between 3D and CAD will develop.

At the RSNA meeting, R2 Technology demonstrated new applications for CAD integrated on TeraRecon's Aquarius 3D postprocessing workstation. The demonstration showed CAD technology working with CT for earlier detection of lung cancer by utilizing R2's LungCheck software. The user interface showed navigation between 2D and 3D information, and reporting tools included nodule measurement. The integrated system automatically generated a report that contained nodules detected by the CAD algorithms.

"CAD for CT is rapidly becoming a key technology, which will support radiologists," said Robert Taylor, Ph.D., executive vice president of TeraRecon. "The technology developed by R2 is a welcome complement to TeraRecon's imaging capabilities."

Increasing ease of use could accelerate the adoption of CAD and other applications. TeraRecon has developed an innovative client server approach that distributes 3D processing power across a hospital's network without the need to install multiple advanced workstations. The company's Aquarius workstation provides the processing power needed to drive sophisticated postprocessing algorithms across a network of distributed PCs accessing the TeraRecon workstation server.

The combination of CAD and postprocessing technologies may grow more popular as the overall market for 3D postprocessing workstations grows. This trend is becoming increasingly likely with the rising profile of 3D among established workstation developers, such as Cedara and TeraRecon, and the increasing roster of small vendors. Radiologists and vendors are recognizing that 3D imaging could be the means by which MR and CT expand into new clinical applications.

Vendors have taken two approaches. One is based on postprocessing software running on standard Pentium PCs. Purveyors of this approach include Voxar, 3DMed, and Neo Imagery. The other approach is to package specialized 3D software integrated into high-powered specialized workstations with hardware such as video accelerator cards optimized for fast, high-quality 3D imaging. Companies making this choice include TeraRecon and Vital Images.

These companies all seem to agree that virtual colonoscopy (VC) is the way to increase the appeal of their products. This type of post-processing has been associated with advanced computing capabilities, time-consuming reconstruction, and guidance from skilled computer operators. But no more. Voxar, for example, is positioning itself as the provider of VC software that can be easily incorporated into existing computing platforms, such as PACS workstations being provided by Philips, Sectra, and Fuji. Speed and simplicity are the drivers, according to the company, which promises complete processing and reports in six to 10 minutes.

The potential clinical advantages are obvious. VC promises fewer risks and less discomfort to patients, compared with conventional colonoscopy. The downside is that it does not allow the removal of polyps at the same time as diagnosis and, therefore, will never replace conventional colonoscopy. Rather, VC will serve—potentially—as a screening tool that identifies suspicious polyps for later removal. A remaining hurdle, the lack of reimbursement, will be overcome if the technology proves diagnostically effective and economically viable. Vendors are already trying to get ahead of the curve, and optimism is high.

"I see virtual colonoscopy as a checklist item, similar to standard MIP (maximum intensity projection) and MPR (multiplanar reformating) functionality that users expect on most 3D postprocessing workstations," said Loris Sartor, Cedara vice president for sales.

Cedara's VC software enables operators to point at and pull out structures for 3D viewing, using the company's point and click classification. This functionality will be included in Cedara software scheduled for release in March.

To speed the transition to mainstream practice, Vital Images has shaped a novel joint marketing agreement with EZ-EM to package that company's VC preparation products with its own postprocessing technology. Vital Images uses its flagship Vitrea workstation, now in version 2.5. Formerly based on the SGI platform, the product has been moved to a standard off-the-shelf NT platform integrated with the display card.

Several smaller postprocessing software vendors see 3D as a growth market and are jockeying for market share. These companies, which include AccuImage, Cybermed, and Neo Imagery Technologies, are exemplified by 3DMed. The three-year-old software company, based in Seoul, Korea, received FDA clearance late last year for its postprocessing package, called Rapidia. This flagship product is an advanced PC-based 3D application offering high performance at an economical price. Physicians had input into its design and the development of its applications. Speed, utility, and economy are also the staples of software developed by Neo Imagery, which touts its product as the fastest volume-rendering system available.

Most telling among the offerings of these and other such companies is the incorporation of VC into the battery of more generally accepted tools, such as MPR and volume rendering. Their integration foreshadows a continuing refinement of 3D in response to evolving market needs and consequent demands and suggests that 3D is all but inevitable.