Siemens plans integrated fast MRI

Despite the onset of health-care reform, there is still room inmedical imaging for good old-fashioned technological innovation.This year's Radiological Society of North America meeting is acase in point, particularly in MRI. Industry leaders Siemens andGE will both unveil radical new scanners designed to make interventionalMRI a clinical reality (see story, page one).

The competition is also heating up in fast MRI. GE has garneredmuch of the attention to date due to its collaboration with echo-planarimaging developer Advanced NMR (SCAN 9/22/93). GE has exclusiverights to Advanced NMR's InstaScan EPI upgrade for Signa 1.5-teslascanners, which it plans to sell until it introduces its own EPIpackage.

Siemens is about to steal some of GE's limelight, however.At the RSNA meeting, the German vendor will unveil Magnetom Vision,an upgrade package to its 1.5-tesla Magnetom SP scanner. MagnetomVision will serve as the platform for an integrated echo-planarimaging package to be released next year, according to ThomasMiller, manager of worldwide MRI for Siemens.

Vision will allow Siemens to enter the market with an integratedEPI system before GE's integrated version is available, Millersaid. Despite GE's head start in EPI with Advanced NMR, Millerpredicts that Vision will win the battle of integrated EPI andwill help Siemens usurp GE's leadership position in the 1.5-teslasegment.

"The goal is to leapfrog GE's own 1.5-tesla integratedreal-time MR machine," Miller said. "They will offerthe Advanced NMR solution, and we will offer our integrated Siemenssolution. By the end of 1994 Siemens will have the number-one-selling1.5-tesla system worldwide. GE is going to be overthrown."

At the heart of Magnetom Vision are souped-up 25-millitesla/meteractively shielded gradient coils. The existing configuration ofMagnetom SP uses 10-mtesla/m gradient coils, while Siemens' 1-teslaMagnetom Impact with the Power Package upgrade has 15-mtesla/mgradients.

Fast MRI sequences like gradient and spin echo (GRASE) producesignals so quickly that lower strength gradients have little timeto spatially encode the information. Stronger gradients with fasterswitching will allow MRI scanners like Vision to overcome thissignal reception bottleneck.

Vision also features four-channel digital radio-frequency coils.The scanner runs on a Unix-based SunSPARC 10 workstation and willhave optional color monitors for functional imaging exams. Real-timeimage reconstruction and postprocessing will be possible withthe system, as will 1024-matrix imaging.

"It will come initially loaded with software and sequencesthat will allow you to do functional imaging, coronary arteryexams, perfusion and diffusion imaging, and turbo GRASE, rightout of the box," Miller said. "It's all integrated.You can do a spin echo and one second later do a turbo-GRASE sequenceor a single-shot EPI sequence without changing consoles, withoutswitching hardware, without doing anything."

Siemens is ready to begin shipping Vision as soon as the upgradereceives Food and Drug Administration 510(k) marketing clearance,Miller said.

Siemens hopes to have 20 or 30 Vision systems installed inthe U.S. by April. These scanners will establish a clinical beachheadin functional imaging that Siemens can exploit when its EPI packageis released in mid-1994.

The EPI upgrade for Vision scanners will consist of the additionof a small electronic booster to the main gradient power supply.Downtime for installation of the EPI upgrade will total six hours,according to Miller.

Vision will make Magnetom SP scanners EPI-ready, but the upgradehas ramifications beyond fast scanning. Other MRI applications,such as MR angiography, small field-of-view protocols, and normalimaging sequences will also improve, thanks to Vision's powerfulgradients, Miller said.

"Gradients have become the horsepower of the MRI industry,"he said. "It was once thought to be field strength, and fieldstrength certainly is one aspect (of performance). But numbertwo of what's under the hood is the gradient system these days.And no one will be able to touch (Vision)."