The Discovery CT750 HD FREEdom Edition offers intelligent motion correction thanks to GE?s SnapShot Freeze technology.
In the consumer point-and-shoot camera industry, there have been a number of technological advancements in recent years, perhaps none more significant than the optical image stabilization techniques that have enabled slower shutter speeds to correct for image blur through corrective algorithms. GE Healthcare, searching for a way to address primary concerns with cardiac imaging—including coronary motion, high heart rates, calcium blooming, plaque composition, and accurate myocardial perfusion—took a similar approach, developing the Discovery CT750 HD FREEdom Edition.
“It’s a lot like in the digital camera industry,” said Scott Schubert, GE CT’s Global Chief Marketing Officer. “They came out with optical image stabilization techniques—OIS—because they learned that you can’t come up with a fast enough shutter speed on a digital camera to take a picture of certain moving objects. They use a rapid sequence technique to acquire multiple digital images and then use the OIS technology to correct for the motion. So we took a page out of their playbook, and we think we now have a better way to correct for coronary motion.”
The Discovery CT750 HD FREEdom (Fast Registered Energies & ECG) Edition offers intelligent motion correction via GE’s SnapShot Freeze technology. In addition, the system features Calcium FREEdom software, which enhances coronary visualization using Gemstone Spectral Imaging (GSI) Cardiac, and Horizon FREE, which features plaque material composition assessment and accurate perfusion calculations.
Development of the system began 3 years ago when GE was searching for a way to correct for cardiac motion. The development team quickly realized that while rotating the scanner faster will solve many of these problems, it may be impossible to rotate the scanner quickly enough to completely eliminate the appearance of cardiac movement in the image.
“Rotating the scanner faster certainly helps, but it’s not sufficient to freeze the coronary motion,” said Schubert. “The reason for that is because the heart beats in a very elastic way. During systole, the left ventricle is compressing and there is a lot of motion on the left side of the heart. During diastole, the opposite: there is more motion on the right side. So you get different amounts of motion, and the motion is different in different phases. Just rotating faster can’t solve the elasticity of the motion of the heart. That was the inspiration behind why SnapShot Freeze and a breakthrough intelligent motion correction algorithm had the potential to do a much better job than the gantry rotation speed alone.”
In order to test the algorithm employed by the Discovery CT750 HD FREEdom Edition, GE imaged its cardiac phantom and found a sixfold reduction in blurring due to cardiac motion. How does that translate to an increased scanner rotation?
“You would have to rotate the scanner at about .058 rotations or 58 milliseconds to get that kind of motion reduction,” said Schubert. “That’s three to four times faster than any CT scanner on the planet today can rotate so our technology evaluation really demonstrated that this intelligent motion correction approach has the opportunity to get much better results at freezing coronary motion than just trying to rotate the scanner hardware faster.”
Currently, the CT system is US Food and Drug Administration (FDA) 510(k) pending. GE submitted the system to the FDA for approval on March 16. The staff at GE is hopeful that the evaluation process will go smoothly and successfully.
When or if the Discovery CT750 HD FREEdom Edition earns FDA clearance, GE is hopeful that the system will not only enhance patient care but also enable physicians to provide less invasive procedures. Schubert referenced the ACRIN PA and ROMICAT studies to show the various improvements that noninvasive cardiac imaging can offer to patients.
“The promise and opportunity with noninvasive imaging of the coronaries is that cardiac CT could be the gateway to the cath lab or therapy,” said Schubert. “Many clinicians would like to use a noninvasive technique like cardiac CT to assess the patient in a definitive way in order to make the therapeutic decision that’s best for that patient. Essentially, the SnapShot Freeze allows these noninvasive cardiac CT tests to be used more broadly for patients with variable and higher heart rates.”
