GE turns CT discussions from slices to volumes

GE's LightSpeed VCT captures the heart and coronaries in fewer than five heartbeats. (Provided by GE Healthcare)GE Healthcare hopes that its flagship LightSpeed VCT will lift the company out of the slice rut into which the CT industry has fallen. The company is positioning the premium scanner as the first true volumetric scanner.At the RSNA meeting, GE staff will explain that the LightSpeed VCT operates in a fundamentally different way from its predecessors, acquiring and presenting data in three dimensions rather than the usual two. For the past six years, CT vendors, including GE, have defined their scanners by the number of slices they generate in each turn around the gantry. In Chicago, GE will speak volumes as well as slices.Reconstruction filters on the scanner generate slices at different thicknesses to provide varying levels of noise and image quality. Reformatting tools present the data the way the physician wants to see them, according to Peter Arduini, general manager of functional and CT imaging at GE Healthcare. Productivity is the common denominator."All the volumetric reconstructions will be there-all the sagittal, coronal, and oblique reformats," Arduini said. "The images will be automatically routed to the filmer and PACS at the appropriate slice thickness and resolution."LightSpeed VCT will expose patients to less radiation dose than the 16-slice scanner, due to the new V-Res detector, which delivers high resolution and wide coverage while more effectively using radiation."With earlier designs, dose was wasted due to overbeaming, which spreads the dose over the side of four-, eight-, or 16-row detectors," said Scott Schubert, global product manager for CT at GE Healthcare. "Because the 64-row detector is wider, it has less overbeaming and is more efficient."VCT entered the U.S. market earlier this year. The first clinical site, Froedtert Hospital in Milwaukee, has been using it since June, and sales to early adopters began in late summer. Full production and routine deliveries should be in full swing by year's end.Early results have documented the new product's power and speed. The VCT captures any static organ in a second, scans from head to toe in five seconds, and captures the heart and coronaries with prospective gating in fewer than five heartbeats. Faster scans will be particularly important in trauma, neuro, angiography, pulmonary, and cardiac applications. The VCT promises to be especially effective at freezing motion in the cardiovascular system, and imaging the coronaries could be its biggest application, according to GE executives.The coronaries move four to five times the diameter of the lumen with each heartbeat, and 16-slice scanners must average the coronaries over 15 to 20 beats, which is too great a time span to achieve high-resolution images. VCT reduces that number to four or five beats.The ability to generate 64 slices per rotation at 0.625-mm resolution puts the LightSpeed VCT on a par with or ahead of the most advanced CTs entering the marketplace. But purchasing decisions are based on more than just the number or size of slices; ease of installation and ease of use are also critical. In this respect, the VCT will appeal to the installed base of LightSpeed owners."The VCT can be bolted literally into the same room as a 16-slice LightSpeed," said Gary R. Strong, manager of new product programs, global CT engineering. The new scanner has the same power and air conditioning requirements, gantry and user interface controls, software and filming interfaces, and autofilming and autoarchiving as the 16-slice version."So customers don't have to learn how to run a VCT," Strong said. "They already know."These advantages will be especially important with this latest generation of CTs, which are priced higher than any previous systems. Older flagship scanners sold for about $1.1 million, but the industry consensus is that these new scanners will be priced at $1.5 million and higher. Customers will want to be sure they are getting value for their dollar.Prospective customers will be treated to about as much detail as they can absorb in their quest to validate GE's approach to 64-slice scanning. GE execs have constructed a persuasive argument in the form of assemblies and electronics that, if not available at their RSNA booth, will be wheeled out for visitors to their manufacturing plant in Milwaukee.LightSpeed VCT represents a new generation of detector technology that incorporates advanced signal processing electronics and an enhanced form of the HiLight ceramics that GE has built into its CT detectors for the better part of a decade. Both came out of GE's Global Research Center in Schenectady, NY, where engineers boosted performance by tweaking light output and afterglow and designed application-specific integrated circuits with the power to keep up with the new detector.LightSpeed VCT has been designed for upgradability as well as high performance, according to Brian Duchinsky, global general manager of GE's CT business. Some of the components built into the VCT will exceed the performance requirements of the scanners as they are originally configured. LightSpeed VCT, for example, has begun shipping with a 400-msec rotational speed. The mechanism needed to bump that speed to 300 msec, however, has been incorporated into these products. Owners will not be able to access this capability until the faster rotational speed is rigorously tested and its value proven. Once that happens, GE plans to upgrade customers to a faster rotational speed with relative ease in the field.The choices for upgrading GE installed sites have always been decided by what was easiest or most efficient for the customer, Duchinsky said. In the past, going from quad- to 16-slice scanners usually meant replacing the old product with the new one. In customer upgrades to the LightSpeed VCT, however, the foundation in many cases will already be in place.