GE unveils new premium performance CT

GE Healthcare unveiled a new flagship CT scanner May 13 at the International Symposium on Multidetector-Row CT in Las Vegas.

As the show opened, GE executives were hoping for the arrival of clinical images from Froedtert Hospital in Milwaukee, where engineers last week were still installing the new LightSpeed CT750 HD (high definition).

The only externally discernible signs of change are a subtle difference in coloring, imprint of the GE meatball on the right front, and the capital letters HD on the side. GE has completely overhauled the underlying mechanism, however. The new system incorporates a detector with a nonceramic material composed principally of the gemstone garnet, the first new detector material from GE in 20 years; an x-ray tube that adjusts the shape and energy of focal spots; a data acquisition system that optimizes information management; and improved reconstruction software and hardware.

Tests of the integrated system, which is still pending FDA clearance, have documented technical specifications with potentially extraordinary clinical performance. Claims attached as part of GE's 510(k) submission indicate increased spatial resolution to 230 microns, contrast improvement by 33% in the body and 47% in the heart, and the potential to draw data from 101 separate energy levels, revealing information specific to certain clinical conditions, and the reduction or elimination of artifacts.

The CT750 HD is equipped to capture data from those 101 individual energies drawn from the range between 40 kVp and 140 kVp. Thanks to a newly developed x-ray subsystem of tube and generator, energies will switch between high and low in half a millisecond.

GE's spectral imaging looks at structures at the optimal energy level for their visualization, according to Dominic P. Smith, general manager of molecular imaging and CT marketing and advanced applications at GE Healthcare. Certain sweet spots may exist for certain kinds of visualization. Liver lesions, for example, may appear best in the range between 75 kVp and 83 kVp, according to research.

Similarly, energies may be leveraged to reduce artifacts. Calcium might be subtracted from arterial plaque at 80 kVp, thereby eliminating or reducing calcium blooming, Smith said. Images obtained between 100 kVp and 110 kVp show about 50% less beam hardening. This reduction, in turn, may be used to improve the visualization of orthopedic prostheses.

"The body guys, even potentially ortho, haven't had a major change in image quality for a long time - not since we went to 16-slice," Smith said. "We think we have some real gains in this space."

The new system is designed to acquire 21.5 line pairs per centimeter, a marked advance over the 14 to 16 lp/cm benchmark for current 64-slice systems. Cardiac imaging will improve about 47% from between 8 and 10 lp/cm to between 12 and 14 lp/cm.

GE this week will showcase x-ray dose reductions of 50% in scans throughout the body, similar to those achieved using methods applied on earlier LightSpeed versions when imaging the heart.

"We are bringing this philosophy of dose reduction to the body," Smith said. "We are going to take dose out of 65 million procedures done annually the way we did the two million for the heart."