GE Medical Systems updates MR product line with high-end Infinity

Enhancements relate to applications

Expanded applications are the key ingredient of GE Medical Systems' new flagship 1.5T Signa Infinity. The magnet, electronics, and housing are identical to those on the Signa MR/i, the cornerstone of GE offerings for the past several years. New on the Infinity is software that supports high-end applications, as well as sensitivity-encoding technology that dramatically decreases imaging time or improves resolution.

The company has also built into the Infinity, as an option, the dual-gradient TwinSpeed technology unveiled at the 2000 RSNA meeting. By allowing the operator to switch between higher and lower power gradients, TwinSpeed can zoom in on a particular body region at high resolution or pan out to cover a broader area. Quiet Technology onboard TwinSpeed reduces acoustic noise by 40%.

"The big distinguishers are the new applications we brought forward with (software) release 9.0," said Dennis Cooke, GE's general manager of Global MR.

Notable among the new applications is fluoro-triggered MR angiography, which allows a one-second switching time. With this capability, physicians are unlikely to miss the bolus of contrast medium administered at the start of angiography procedures. The new software package allows comprehensive cardiovascular imaging, defined as a complete cardiology exam completed in 30 minutes, including wall motion, perfusion, delayed enhancement, and coronary angiography.

Ultrafast breath-hold abdominal imaging, which reduces breath-hold from 20 to 10 seconds, virtually eliminates motion artifact. This advance is achieved through the use of ASSET, the company's version of sensitivity encoding. The major vendors have each been developing sensitivity encoding as a means to get more data from each scan. ASSET relies on a set of phased-array surface coils and advanced pulse sequences.

Two other applications, 3D prostate imaging and 3D brain spectroscopy, are also key. While prostate imaging is not yet a mainstream application in MR, it could become one under the right conditions, according to Michael Harsh, general manager of MR engineering.

"What MR can bring to the party is being able to do metabolites and look at what is happening at that level, which is more than ultrasound can bring," Harsh said.

Infinity uses an endocavity probe to obtain high-resolution MR scans of the prostate. The probe is supplied by an outside manufacturer, but company engineers are developing their own version for future release.

The brain spectroscopy package holds particular importance through its ability to deliver a 3D volume.

"Rather than 2D, you get a 3D voxel, so you are able to acquire with the volume you want, looking for the metabolites that indicate a tumor," Cooke said.