Premium scanners reach plateau in hardware but not applications

Vendors add price points below 16-slice level

Manufacturers are putting their development of superpremium CT scanners on cruise control in favor of other technological offshoots. Although some manufacturers are already experimenting with CT-optimized flat-panel detectors, their commercial release is a long way off, according to industry executives. The current generation of 16-slice scanners is likely to last for the coming several years.

"The 16-slice scanners meet or exceed all of today's medical demands," said Markus B. Lusser, Siemens' segment manger for radiology CT. "Now we must refine the applications and develop new visualization and evaluation techniques."

Among these is computer-aided detection. Several software packages are being groomed to identify and characterize lung nodules. These include ImageChecker CT from R2 Technology, whose turnkey workstation version received FDA clearance Nov. 20 (SCAN 1/8/02). GE used the RSNA meeting to introduce its CT Advanced Lung Analysis, which automatically measures and characterizes the growth of lung nodules, while providing 3D views to allow qualitative assessment. Siemens is evolving similarly advanced quantitative and qualitative tools as part of InSpace, a second console the company has added to its flagship Sensation 16.

"With InSpace, you break with traditional CT viewing," Lusser said. "You go into an isotropic real-time viewing environment where structures can be viewed in arbitrary planes with various thicknesses."

A broad area of growing interest is cardiology. At the RSNA meeting, Toshiba America Medical Systems highlighted the cardiac visualization techniques possible with its Aquilion Multi 16. Key to the product's success are its temporal and spatial resolutions. With a 400-msec rotational speed, the scanner, which began routine shipments in December, edged out competitors by 20 msec. Its 40-row Quantum Detector covers 32 mm with 16 slices, each 0.5-mm thick, but special algorithms push resolution to about 0.35 mm, according to the company.

The exceptional resolving power of the scanner allows quantitative and qualitative assessments of the heart, including ejection fraction, wall motion, and wall thickening. Data can be formatted into polar mapping techniques similar to those used in nuclear cardiology to show regional cardiac function.

"We have integrated our nuclear medicine techniques to display regional functions of the heart in the single spherical map that cardiologists are used to seeing," said Doug Ryan, director of the Toshiba America CT business unit.

Potentially, 16-slice scanners may be applied to image coronary arteries as well as detect and quantify soft plaques. They may be used in a comprehensive manner to perform complete cardiovascular workups, said Jim Green, senior vice president and general manager of CT at Philips.

"These systems can do a full CT angiogram from head to toe," he said. "They are capable of changing the way emergency medicine is performed--the way patients are staged when they show up with trauma, how they are checked for stroke and for heart attack."

After keeping promises--some made as long as two years ago--to deliver 16-slice scanners to the marketplace in 2002, CT makers are hoping to get as much from those expensive platforms as they can. Philips Medical Systems and Siemens Medical Solutions appear intent on filling price-point gaps beneath their flagship products.

Both companies exhibited 10-slice scanners at the RSNA meeting. Each was announced before the exhibit floor opened: the Siemens' Sensation 10 in October (SCAN 10/9/02) and the 10-slice version of Philips' MX8000 IDT in November (SCAN 11/27/02 ). But Siemens went one step further, also introducing a six-slice version of its midtier Emotion platform.

The latest addition to the Emotion family is being positioned as the company's workhorse for routine CT scanning of chest, abdomen, and pelvis, with the ability to perform routine angiography, although this product--like its 10-slice brethren--can also visualize the heart, lungs, and colon.

The new products generally go for less than $1 million, but actual prices depend on their clinical configurations. The 10-slice scanners are upgradable to superpremium configurations, as each is built on the same basic platform as the 16-slice products. Siemens' six-slice CT is on a different track, yet the new scanner shares many of the same technologies as the Sensation products, as do other members of the Emotion family configured for single- or dual-slice scanning.

The Sensation and Emotion multislice families provide Siemens with a lot of flexibility, according to Lusser.

"We can hit every price point," he said. "Whatever the customer wants, we have it."

Eventually, customers will want flat-panel detectors built for CT applications. In collaboration with researchers at Massachusetts General Hospital, Siemens engineers have already produced clinical images with a 1024-slice flat panel, Lusser said. A commercial system is years away. Clinical images created thus far have been done on a flat-panel prototype.

The time needed to refine this flat-panel technology may be just what the imaging community needs. Practitioners are in a transition stage, Lusser said. They need some time to adjust the way they practice medicine.

"Many customers who buy 16-slice scanners still run them like fast single-slice machines," he said. "But these scanners are so much more than that. With sophisticated visualization techniques, they will redefine the practice of medicine."