Siemens seeks to redefine CT with RSNA unveiling

Executives at Siemens Medical Solutions hope to end eight years of slice wars with a work-in-progress CT platform unveiled this week at the RSNA meeting.

Definition AS (Adaptive Scanning) takes image quality to a new level, according to Peter Kingma, Siemens vice president for CT, delivering 0.24-mm pixel spatial resolution and boosting temporal resolution with 300-millisecond rotations, 30 msec faster than the current industry benchmark.

"That 10% window allows more measurements in a set time, helping to resolve complex clinical structures," Kingma said.

An example is the coronary artery, which typically moves in several planes as the heart beats. If this artery is burdened by calcium, its movements can create a blooming artifact or shadow inside the artery that can be mistaken for soft plaque buildup, Kingma said.

"Physicians want to be very certain about this condition, if it is there," he said. "The Definition AS can provide that certainty."

Heightened spatial and temporal resolution vastly improves the potential for stroke assessment and characterization of cancerous tissue, according to Kingma. The risk presented by aneurysms can be better assessed through vascular kinematics demonstrated using blood flow analysis now possible with the Definition AS.

Workflow is aided by a 30-mega heat unit x-ray tube that allows the system to run at high power levels for as many patients as needed without downtime for cooling, Kingma said. This could prove important inside and outside the diagnostic realm.

"We see CT as an interventional tool with potential far beyond what is currently in use in CT fluoroscopy," he said. "We see the potential to design a scanner that has a dedicated processor that can do complex interventional procedures in 3D, tracking a needle as it enters the patient and moves toward the lesion far more accurately and safely than is now being done."

Definition AS, currently a work-in-progress but slated to begin shipping in May 2008, bears the class name of Siemens' dual-beam scanner, unveiled two years ago, even though it uses only a single x-ray beam. It is so named because Definition AS incorporates other advanced technologies found in the Definition platform.

"This is a totally different system that has the DNA of the best-of-breed innovations we have brought out over the last 10 years," Kingma said. "But it is an absolutely new platform."

The scanner is dubbed "adaptive" to make a point about its versatility, which is apparent already on the assembly line. Definition AS can be configured with 20, 32, or 64 detector rows. Siemens' z-Sharp technology doubles the number of slices per rotation, but the results are what count, not the number of slices, Kingma said.

"This is not just about a scanner with more detector rows," he said. "We truly want to distance ourselves from (detector rows) as a technological or clinical positioning tool."