MR vendors seize on clinical opportunities in their evolution of scanners, subsystems

February 7, 2005

MR developers, once addicted to technology for technology’s sake, have turned to finesse, tweaking designs to do more clinically with advanced versions of what they already have.

MR developers, once addicted to technology for technology's sake, have turned to finesse, tweaking designs to do more clinically with advanced versions of what they already have.

At the 2004 RSNA meeting, GE Healthcare improved upon its data pipeline to bolster data flow at different field strengths. Siemens Medical Solutions stretched its Total Imaging Matrix (TIM) body coil technology from 1.5T to 3T, while bumping up its parallel imaging capability to accelerate data acquisition. Toshiba filled the gradient gap with midrange coils on its flagship 1.5T scanner, while whetting the interest of exhibit-goers with a glimpse of its evolving midfield MR mammography capability. Hitachi provided upgrades for its midfield Airis installed base and higher field Altaire 0.7.

Even products that appeared to be major departures from the past had been, in fact, foreshadowed long before their arrival. Insightec's ultrasonic therapy, shown for the first time at the RSNA meeting integrated with GE's MR guidance and monitoring, goes back to a prototype first built in 1995 (SCAN 9/29/04). Attempts to use focused ultrasound as a therapeutic tool go back even further, to the 1940s.

Philips' new high-field open MR, the Panorama 1.0T, has roots extending to 1999, when the company announced it had begun developing the scanner (SCAN 10/26/06).

Siemens' ultracompact 1.5T Espree, whose bore is so thin it looks like a CT gantry, is the culmination of more than a decade of efforts to make magnets thinner (SCAN 10/26/04).

Esaote's tilting gantry on board the new G-Scan is the first MR scanner to take the patient from a supine to a standing position (see accompanying story, this issue). But it was preceded by another system, in this case Fonar's Upright MRI (formerly known as the Stand-up MRI), which was first described in 1998 (SCAN 10/14/98).

These latest enhancements are noteworthy, but most of their significance comes from their clinical applications. Insightec's ExAblate, for example, may have an enormous impact on patient care. The system was approved late last year by the FDA to treat patients with uterine fibroids, but the company doesn't plan to stop there.

"We think this is the first step toward totally noninvasive therapy," said Lynn Golumbic, InSightec marketing manager. "It will be to the operating room of the future what minimally invasive surgery was to invasive surgery."

The Panorama 1.0T and Espree offer high-field image quality in a patient-friendly environment. G-Scan promises evaluations of the spine in conventional as well as weight-bearing states.

Tweaking technology to achieve a purpose is the new style of the radiology industry. GE's Excite High Definition (HD) pipeline can support 32-, 48-, and 64-channel coils. The company primed the pump with the launch of a 32-element peripheral vascular coil that extends to the lower leg and foot.

The faster the data acquisition, the less vulnerable the scan to artifacts caused by patient movement. Several difficult-to-image patient populations will immediately benefit from the added speed, according to Dave Weber, manager of GE's global high-field MR business.

"We can now actually do unsedated pediatric imaging of the brain, which is a tremendous benefit to physicians who scan a lot of kids because of the cost and risk involved in sedation," he said.

Weber noted that brain scans of demented patients will also be easier because of HDMR's speed.

Siemens adapted TIM to run on its 3T whole-body Trio. Tied into this coil set is the next iteration of the company's parallel imaging technology, called iPAT², which takes users to a new level of performance. With iPAT², data can be acquired up to 12 times faster than with conventional MR, according to Jeff Bundy, Ph.D., Siemens' director of MR R&D.

"A lot of innovation with collaborators is being focused on exploiting the parallel imaging capabilities of TIM," he said.

Toshiba's plans for the Ultra scanner are similarly ambitious, but on a different plane. The company wants to extend the clinical reach of its 0.35T open scanner to include diagnostic MR mammography. Typically, high-field scanners are used for this purpose, because of the demanding imaging protocols. Last year, the company boosted its gradients to deliver an amplitude of 25 mT/m and slew rate of 100 mT/m/sec, enough to achieve the image quality needed for diagnostic breast MR.

Toshiba engineers are now working with a luminary site to refine the needed protocols to work with the Ultra and developing a new breast coil to allow MR-guided biopsy. The goal, according to Bob Giegerich, director of Toshiba's MR and nuclear medicine business units, is to offer a breast imaging package that will provide everything the physician needs, including MR fluoroscopy and an in-room monitor, by the middle of this year.

"Because if you have to run out to the console to see the images, what good is the scanner?" he said.