GE unveils twin-gradient MRI scanner for general and specialized imaging

By Greg Freiherr

GE Medical Systems has combined the attributes of a general-

purpose and specialty MRI scanner into a single unit. Called TwinSpeed, the system has a body-gradient coil for general-purpose imaging and a supplementary coil for specialized studies of the heart and brain.

"You enable cardiac and functional imaging (of the brain) but you don't sacrifice 48-cm spine work," said Dennis C. Cooke, manager of GE's global MR business.

The new product is also designed for patient comfort. Sound baffling equipment reduces the noise of a scan by 40%. The vibrations caused by gradients during pulse sequences are amplified as they travel through the interior of the scanner. These vibrations peak as they flow through scanner covers, which act like the acoustic backing in audio speakers and amplify the banging and screeching.

GE engineers are exploring whether this "quiet technology" might be applied to other MRIs in the company's product line.

The twin-gradient product, which was announced at the RSNA meeting and has received FDA clearance, will go into full production in the third quarter of 2001. Sales will be directed at cardiologists, neurologists, and radiologists. A price tag of up to $2 million will limit sales to a select group of early adopters. Buyers will want the

high resolution found on optimized systems, but they are likely to hedge their bets by maintaining whole-body imaging capability, said Jeffrey A. McCaulley, general manager, GEMS Americas MR sales and marketing.

"People who want to do optimized cardiovascular imaging are going to come after this, and that means both cardiology and radiology. People who want to do neuro imaging at 1.5 tesla will want it. Then there's the whole-body imaging, which clearly hits home with radiologists," McCaulley said. "This is a product that fits a broad (range) of applications that we think will appeal to everyone."

TwinSpeed is a new version of an idea that first appeared about five years ago as the Prima 1TG from Elscint. That system, like the TwinSpeed, provided a wide field-of-view at relatively low resolution. This FOV could be narrowed to achieve a higher resolution by switching from the body coil to a specialized coil. What is different on the TwinSpeed is GE's proprietary quiet technology. TwinSpeed also operates at a higher field strength‹1.5 tesla compared to 1 tesla for the Prima 1TG.

GE acquired the technology in 1998 after buying Elscint's MRI assets. Among the resources included in that deal was the R&D center in Haifa, Israel, where engineers first developed and have continued to refine the twin-gradient platform. The center has been the source of advanced MRI technology for GE, including the company's 3-tesla system and the dedicated interventional Signa SP, also known as the double doughnut.

Cooke said TwinSpeed will have a strong and immediate impact on the MRI marketplace, because noise reduction will appeal to patients. But the twin-gradient design may be more important.

"Gradient performance is what it is all about in MRI, and we have all reached a natural limit." he said. "We have shown a way to break through that barrier. It's clear that everyone is wrestling with the same physics limitations we are. We have now shown people how to go beyond them." n