CT vendors jockey for opportunities arising in cardiovascular market

Siemens and Philips go with multislice, GE banks on EBT

CT hasn't yet reached the point of being truly competitive with cardiac cath, but it's close enough that vendors can sense a major market opportunity in the making.

"Cardiologists are more and more interested in doing CT imaging, whether by themselves or using the radiology department as a service provider," said Andre Hartung, product manager for preventive care in Siemens' CT division.

Siemens, Philips, and GE each brought to the annual meeting of the American Heart Association on Nov. 18 its own distinct strategy for tapping into this demand. Siemens displayed the Sensation Cardiac, an adaptation of its flagship 16-slice scanner that's been loaded with software tuned for cardiovascular applications. Branding the system specifically for cardiology was designed to overcome a psychological barrier between the cardiology community and CT.

"Cardiologists like to have something they can identify with and that is one of the major reasons that we have branded the Sensation Cardiac as a dedicated cardiac system," Hartung said.

Philips took a different approach, bringing a 16-slice scanner optimized--but not named--for cardiology. Philips' team sought to take the marketing high ground armed with technical facts about the capabilities of its Mx8000 IDT (infinite detector technology). In keeping with recommendations from the American College of Cardiology, Philips wants to provide cardiologists with a tool that can expand their practices, according to Phil Prather, Philips' market director of cardiology products.

"A multislice CT system allows you to address the cardiac and the vascular system, and to do organ perfusion analysis," he said.

Neither Toshiba America nor GE brought its multislice CT to the show. Toshiba decided instead to focus on echocardiography. GE pushed aside the 16-slice LightSpeed in favor of its electron beam technology, the technological jewel of its acquisition of Imatron a year ago.

The EBT scanner, dubbed e-Speed, had an advantage from the outset, as Imatron products based on electron beams have traditionally been marketed as dedicated cardiology scanners. EBT has helped raise cardiologists' awareness of CT's potential in this field.

What better place than the AHA meeting, therefore, to formally unveil the latest version of EBT? Visitors to GE's booth heard claims related to the increased speed and enhanced spatial resolution possible with e-Speed, which had cleared the FDA only a month earlier.

Temporal resolution, always a hallmark of electron beam scanning, has improved to allow a single-slice scan in as little as 33 msec. Slower speeds of 50 msec and 100 msec are also possible, according to GE.

In the past, EBT has been spatially challenged, a condition that one radiologist described as "photon deprived." The new e-Speed addresses that weakness, according to GE, with enhanced technology that trims the slice thickness from the previous best of 3 mm to 1.5 mm.

Competitors noted, however, that e-Speed's spatial resolution still trails that of mechanical scanners, which generate submillimeter slices, and pointed to the improving temporal resolution of their own machines.

E-Speed's strength--its packaging as a dedicated cardiology scanner--may turn out to be a weakness. Philips staff touted the Mx8000's capabilities outside cardiology as an advantage for cardiologists wanting to get into vascular applications typically outside the bounds of cardiology.

But GE may have that covered. Thinking ahead, Imatron several years ago obtained FDA clearance to market its EBT system for advanced radiological applications, such as lung scanning and virtual colonoscopy. GE Imatron preserved this option in its latest FDA filing. An FDA document accompanying the agency's Oct. 11 clearance of e-Speed describes the applications for which it can be marketed.

Included is visualization of the heart, blood vessels, lungs, and lymphatic system in 2D and 3D, fly-throughs of the colon, blood vessels, and airways, real-time motion studies, vascular and tissue blood flow analysis, and the determination of quantitative data pertaining to calcium or other materials in bone, tumors, or organs.

Other questions were raised about the relative merits of EBT versus multislice scanning. Claims that EBT delivers a lower dose than multislice scanners were countered by Prather with assertions that electron beam technology actually deposits four times the dose delivered by mechanical multislice CTs. Additionally, mechanical scanners, such as Philips Mx8000 IDT, provide views of the heart that EBT cannot deliver, he said. These include vessel analysis and the formatting of data to match views commonly achieved using cardiac cath and echocardiography.

Whether multislice CTs have this advantage over GE's new e-Speed, however, is debatable. GE claims its new EBT scanner allows analysis of ventricular and stroke function, provides ejection fraction, and measures myocardial wall motion thickness and mass. The system can render 3D heart volumes, cath views, coronary 3D vessel tree imaging, and short- and long-axis reformats, according to GE. And coronary vessel analysis supports plaque composition measurements.

Prather countered that the lower spatial resolution of e-Speed still gives mechanical scanners the edge.

The winner of this battle may be determined by marketing savvy as much as technological prowess. But if the competition draws attention to the viability of both technologies, as it likely will, there might not be a loser.