CT: A Big Hit, No Matter How You Slice It

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Cardiac imaging and 64-slice was at the heart of CT at last week's Radiological Society of North America meeting. Clinicians and vendors alike are eyeing CT's capabilities to noninvasively step into the realm of diagnostic catheterization, making CT the screening grounds for the cath lab.

Each of the four major CT vendors showed off their 64-slice scanners at the meeting, as many units that debuted at last year's meeting took root in facilities this year. Sixty-four slice CT brings with it the speed necessary to stop a beating heart, literally.  Clinicians report excellent image quality of previously hard-to-image coronary arteries and images on display proved it.

Good news for radiologists came too at last month's American Heart Association meeting where a study was presented that said radiologists still play an important role in CT cardiac imaging, namely in assisting cardiologists with the incidental findings seen during CT angiography studies.

But 64-slice didn't take all the CT buzz at RSNA, with show-goers lining up to see the latest 16, 32 and 40 slice scanners have to offer at a more affordable price point. New workflow enhancements in 3D and virtual colonoscopy as well as image management solutions to deal with the image overload of high slice-count scanners gained a lot of attention. And large bore CT scanners specialized for radiation therapy applications proved popular, too.

(Note: companies appear in alphabetical order.)

GE Healthcare launched two new CT scanners, the LightSpeed VCT and the LightSpeed Pro32 and, and the next-generation of its workflow-enhancing software, Xtream FX.

The LightSpeed VCT (Volume CT), which provides a combination of simultaneous wide volume coverage and high resolution via a 64-channel detector, offers 4 cm coverage and a resolution of 0.35 mm. The most significant clinical application for this system will be cardiac studies. LightSpeed VCT reduces the acquisition time for a typical exam from 20 seconds on a 16-slice scanner to about 5 seconds on this device, GE said. In a single rotation, the system creates 64 submillimeter images, totaling 40 millimeter of anatomical coverage, which are combined to form a 3D view of patient anatomy. It can noninvasively capture the heart in five beats and scan the whole body in 10 seconds, according to GE.

This capability is considered a breakthrough, GE said, because once the contrast agent is injected, there is an initial variation of heart rate produced by introduction of the agent, then there is about a five second "golden window" where the heart rate is stable, followed by an increase in heart rate as the breath-hold produces hypoxia. It is important to have a stable heart rate to produce excellent image quality across an entire population of patients who will be imaged.

The first LightSpeed VCT was installed at Froedtert Hospital in June 2004.

The second product launch involves the LightSpeed Pro32 helical multislice CT, which advances the 16 series scanners. This system is described as being incrementally better compared to the 16-slice scanners, and is beneficial for cardiac studies, angiography, and perfusion studies, GE said. Although it does provide 4 cm coverage, the resolution is not up to the standard of the VCT. 

Both scanners have an increase in scan rotation speed, moving from 400 milliseconds to 350 milliseconds as a single rotation of the detectors.  Both products will be fully commercially available in the first quarter of 2005.

GE also debuted its next-generation Xtream FX workflow technology designed to allow imaging departments to keep pace with the large volume of data generated by routine sub-millimeter scanning. Xtream FX provides thin-slice image reconstruction that GE said is 3.7 to 6.9 times faster than other industry standard platforms. It is three times faster than the existing Xtream engine.

Philips Medical Systems debuted the new Brilliance CT 64-channel scanner, the big brother of the Brilliance 40-channel scanner, as well as touting a new large bore CT scanner for radiation oncology.

The Brilliance CT 64 scanner delivers thin-slice acquisition for the full width of the detector module by increasing the number of simultaneously acquired data acquisition channels to 64 per rotation, Philips said. Applications include neuro, body, pulmonary, cardiovascular, pediatric, interventional and trauma studies. Commercial shipments are scheduled to begin in June or July 2005, according to James Fulton,