Siemens seeks balanced portfolio of CT offerings

Heart image obtained with Siemens' Sensation 64 demonstrates improved resolution with the company's unique dual focal spot. (Provided by Siemens Medical Solutions)In an industry that has come to define itself by numbers, Siemens Medical Solutions stands alone. According to company executives, it's not the number of CT slices that's important, nor the number of channels carrying data from the detector, and not even the speed at which the CT gantry turns. It's the resolution and robustness of the system and its ability to meet clinical needs within specific budgets.Although vendors have focused a great deal of attention on flagship 64-slice scanners and their potential for cardiovascular applications, Siemens is also emphasizing low- and midrange solutions. It will reinforce that message at the RSNA meeting, where its booth will not only offer clinical proof that 64-slice technology meets the clinical needs of high-end users, but will emphasize that the 10- and 16-slice members of the Sensation family, complemented by the dual-, quad- and six-slice Emotion scanners, meet the needs of the rest of the imaging community."Our commitment to innovation does not hold true at just the top end of technology, but it also takes place throughout the whole multislice product line, where we address all levels of clinical and budget needs with $250,000 to $1.5 million-plus scanners," said Dr. Bernd Ohnesorge, director of CT marketing. "It requires a lot of innovation to provide multislice scanners for everybody's budgets."Booth staff will describe how the company has worked to advance the capabilities of CT scanners across the Siemens portfolio. Much of that work has been done on the low- and mid-tier products now flying under the radar, said Bappa Choudhury, vice president of Siemens' CT division in the U.S.They will also have a story to tell about their flagship product, the Sensation 64. With this technology, Siemens has taken the path less traveled, developing a 64-slice scanner that uses a unique dual focal spot. The approach has made the company vulnerable to attack: When the Sensation 64 was unveiled at last year's RSNA meeting, competitors were quick to point out that the scanner's solid-state detector has only 32 rows. They have alleged that Siemens is gaming the numbers and that the scanner does not deliver 64 true slices per rotation, but 32 slices two times."Competitors are bringing that up, but the physicians we talk to are very comfortable with the quality they get from this special design," Ohnesorge said.Siemens' novel approach to slices achieves images with an effective resolution of 0.4 mm, 25% to 50% better than competing systems. It uses two focal spots that sample 32 rows simultaneously, creating 64 slices by multiplying 32 by a factor of two. The resolution is better, according to the company, because the tissue is sampled twice from varying angles.Many prospective customers are buying the argument. Siemens expects that about 100 64-slice scanners will have been installed by the start of the RSNA meeting. Most orders have been for the general-purpose Sensation 64, which lists for $1.5 million and is positioned for use in neurology, pediatrics, and trauma.The Sensation Cardiac 64, the configuration optimized for coronary CT angiography, accounts for about 30% of the orders. Its added capabilities, which impose a premium of about $200,000, include calcium scoring, vessel view, an Argus heart-function tool, Speed4D workflow package, and a gantry capable of 0.33-second rotation. These are options on the general-purpose Sensation 64, which has a standard gantry speed of 0.37 second.At the accelerated rotational speed possible with the dedicated cardiovascular system, the Sensation Cardiac 64 generates 200 slices per second with a temporal resolution as short as 83 msec, achieved by mathematically recalculating data obtained during ECG gating. At a standard gantry speed of 370 msec, the Sensation 64 can achieve a temporal resolution of 94 msec.The Sensation Cardiac might be capable of differentiating soft and hard plaques, according to Siemens, by sorting plaques into three categories based on their Hounsfield qualities: calcified, fibrous calcified, and noncalcified. This differentiation is currently possible with intravascular ultrasound but not with coronary angiography. The latter can determine only the degree of stenosis, not how likely the plaque is to rupture and create a thrombus that blocks blood flow. The ability to evaluate factors other than stenosis could allow use of this new type of scanner as a noninvasive alternative to diagnostic coronary angiography, freeing cath labs for interventions."We see a rise in interest, with the cardiology community working more closely with radiologists to refer patients as well as to get into the business themselves," Ohnesorge said. "Cardiologists are looking for the next technology or test that might improve care."Siemens luminaries are also exploring the use of 64-slice scanners for virtual colonography. Using this technology, they can detect or rule out the presence of polyps as small as 5 mm, according to Ohnesorge. The company is developing computer-aided detection algorithms to help find lesions in the colon, lungs, and elsewhere."We have a big focus on leveraging the potential of the 64-slice scanners to expand applications but also to facilitate workflow," he said.Finding the sweet spot between accepted and pending applications will drive the sale of the Sensation 64, Siemens executives say. Their goal is to demonstrate at the RSNA meeting that such a spot exists and that different products can meet different clinical needs.