Toshiba grooms new 1.5T MR scanner for U.S. high-field market

September 24, 2003

Short-bore magnet reflects firm's orientation toward patientsOne window of opportunity closed in MR, but another is opening, as Toshiba America Medical Systems prepares to make good on plans to enter the compact high-field market.

Short-bore magnet reflects firm's orientation toward patients

One window of opportunity closed in MR, but another is opening, as Toshiba America Medical Systems prepares to make good on plans to enter the compact high-field market. A magnet initially supplied to Marconi and later to Philips for the Infinion system has become the cornerstone of Toshiba's Excelart Vantage, a 1.5T scanner that Toshiba will market as a hybrid of patient comfort and high performance.

The system, shown as a work-in-progress at the 2002 RSNA meeting and cleared by the FDA Aug. 21, will be launched officially at this year's RSNA meeting. By that time, company executives expect to have at least one high-profile show site operating, a small installed base with clinical results, and systems routinely rolling off the production line in Japan headed for the U.S.

In their development of Vantage, Toshiba engineers merged 1.4-meter magnet technology from Oxford Magnet Technology in the U.K. with high-field technologies built into Toshiba's relatively long bore 1.5T system. The new integrated system plays to Toshiba's established strength in the U.S. market as a provider of systems designed for patient comfort. Although the company has not been a major player in the high-field segment, it has achieved success with its midfield open superconducting system Opart. Its success at the high end of CT has further enhanced its corporate credibility.

"The CT product line has put Toshiba in the spotlight relative to high-profile imaging equipment," said Dane Peshe, director of Toshiba's MRI business unit.

Show sites will buff up Toshiba's MR corporate profile even more. Long-time Toshiba supporter Dr. Mark Winkler, director of MRI at the Steinberg Diagnostic Medical Imaging in Las Vegas, will be among the first to acquire a Vantage. But the ranks of Vantage owners will reach beyond the traditional. Toshiba has contracted to install Vantage systems at Good Samaritan Hospital in West Islip on Long Island, NY, and at a freestanding imaging clinic being built by Health Scan Imaging in Murrieta, CA. The company has a backlog of other orders for the system, according to Peshe.

High-field scanners have become increasingly compact over the past decade, following the release in late 1993 of a family of smaller systems by Philips Medical Systems. The availability of short and flared bores muted the appeal of midfield systems whose popularity soared in the mid-1990s amid patient fears of tight spaces.

The magnet built into Toshiba's new product follows that trend. It was initially supplied to Marconi for use in its Infinion system. Infinion changed labels when Philips acquired Marconi Medical two years ago. The system was popular, particularly in the U.S., but Philips dropped the unit in favor of its Intera product line, which is built around magnets supplied by Intermagnetics General of Latham, NY (SCAN 5/28/03). Philips' decision to go exclusively with Intermagnetics apparently opened the door for Toshiba to strike a supply agreement with Oxford Magnet Technology.

Toshiba now claims to have the most compact MR system ever developed, a claim made possible by engineers who wrapped the Oxford-provided magnet tighter than it was on the Infinion. The company will note this fact in sales presentations, along with the assertion that-aside from Infinion-Vantage is the first new 1.5T system to come along in quite awhile, according to Peshe.

Toshiba's decision to create a 1.5T system was spurred by its failure to make substantial inroads in the U.S. market despite 15 years of trying. The Japanese company in 1988 purchased the MR division of Diasonics, which at that time had a substantial percentage of the U.S. installed base. The idea behind the deal was to establish Toshiba as a major player in MR, earn service revenue from installed Diasonics systems, and eventually convert the installed base to Japanese-made MR products. The gambit failed, as independent service organizations snapped up many of the service contracts on installed systems, and owners of Diasonics systems turned up their noses at proposed Toshiba-built replacements.

Development of the Opart superconducting 0.35T system saved Toshiba as an MR provider. The system was designed by U.S. engineers according to the interests of the U.S. market, and it rode the wave of popularity that lifted midfield open scanners to prominence in the mid-1990s. Opart has continued since its introduction in 1996 as the company's only popular MR offering, as efforts to enter the high-field arena have met a lukewarm reception at best.

The company's current Excelart 1.5T family-the AG, XG, AG/S and XG/S-is of an old-fashioned design. Stuck with a large magnet, Toshiba engineers focused on softening the noise that accompanies MR exams, unveiling its sound-muffling technology called Pianissimo at the 1999 RSNA meeting (SCAN 12/15/99).

Toshiba's new Excelart Vantage includes Pianissimo as well as other Excelart high-tech capabilities. The new short-bore system can be configured to deliver linear 30 mT/m gradients with a slew rate of 50T/m/s (tesla per meter per second) or 130T/m/s. It delivers a homogeneous field over the complete 50-cm diameter spherical volume of the bore. This "sweet spot" in the magnetic field is better than the one delivered by magnets made for the Infinion, according to Peshe.

"It's been slightly reworked and improved by Oxford," he said.

Toshiba is quoting a homogeneity spec of two parts per million over a 50-cm dsv (diaspherical volume). Marconi and Philips quoted the Infinion at 2.5 parts per million.

The specs on the gradients match those of the Excelart AG (30 mT/m with a slew of 50T/m/s) and XG (30 mT/m with a slew of 130T/m/s), which is not surprising since the gradient was ported from the current 1.5T line. The major change was adapting the technology to the shorter bore of the Oxford magnet.

The "S" versions of the AG and XG systems, which indicate "spin" configurations, include the company's Speeder proprietary parallel imaging technology. This technology also has been ported to Vantage, according to Peshe.

The Vantage computing platform is based on Intel Xenon processors, which are fast and, as the drivers of Toshiba's computing platform, inexpensive compared with the minisupercomputers that had been a pervasive element of MR scanners in years past.

Vantage will come standard with four channels but will offer an eight-channel option. It will include coils developed by Toshiba, as well as supplier USA Instruments, which was purchased last year by GE Medical Systems (SCAN 12/25/03). GE made a point on purchasing the company of announcing that USAI would continue to provide coils to other OEMs, and Peshe expressed no concerns about the union of the two companies.

"There are firewalls in their relationship that keep them separate," he said.

Included on Vantage is BasicSoft, a range of standard pulse sequences, including high-resolution FSE and single-shot variations of FASE (fast advanced spin-echo) and multislab MRA. The system is available with optional packages for advanced EPI functional, perfusion, diffusion, peripheral MRA, and cardiac imaging.

Vantage also offers advanced sequences including SuperFASE, as well as a half-Fourier radio-frequency refocused sequence for high-speed 2D and 3D T2-weighted imaging, which has been adapted for vascular structures in the abdomen and chest. This technique allows venous and arterial vessels to be visualized simultaneously without the use of contrast agents, improving patient comfort, reducing costs, and enabling the scan to be performed repeatedly if necessary, according to the company.

A lot is riding on this technology. It will be at the center of Toshiba's first concerted effort to crack the high-field marketplace. A rejuvenated sales and marketing team at TAMS will follow a business model proven a decade ago with Opart. The plan is already beginning to pay off.

"It's been gratifying to see the activity that sprouted from the RSNA meeting last year, when we just had the mock-up on display and were talking about the concept," Peshe said. "Vantage is really selling itself."