CT outlook

CT advances have knocked the imaging community back on its heels. The simplistic question of who will control coronary CT angiography has given way to far more perplexing ones about how and when this technology should be used.

Like the ghost of Christmas yet to come, CT will soon have the ability to quantify the risk of future disease. Already CT lung scanning is giving hope to cigarette smokers that they might catch their lung cancer before it catches them. Coronary screening promises the same for those in fear of heart trouble.

But research presented Nov. 14 at the American Heart Association meeting and later published in the New England Journal of Medicine found that angioplasty must be administered soon after a cardiac event and may not be effective if applied more than 24 hours - possibly just 12 hours - afterwards, a finding that could dampen interest in coronary CTA as a screening tool for coronary artery disease (DI SCAN, 11/15/07, Angioplasty loses effect if not performed soon after heart attack).

Raising further concerns about the value of coronary CTA, research published in the Dec. 19 Journal of the American College of Cardiology found that only half the patients with 50% or greater narrowing of the coronaries due to plaque buildup actually have insufficient blood flow to the heart ( DI SCAN, 12/14/07, Coronary CTA lacks certainty as ischemia indicator ).

In the annual oration on diagnostic radiology at the 2006 RSNA meeting, Dr. Kerry M. Link, director of the Center for Biomolecular Imaging at Wake Forest University, argued that advances in cardiac imaging will have a profound and long-lasting effect on medicine, health economics, and especially on the field of radiology.

"We will mark this time as a defining moment and as the beginning of significant changes in radiology's role in medical imaging," he said.

He noted, however, that many radiologists are hesitant, if not downright reluctant, to embrace cardiac imaging, especially coronary CT angiography.

And this was just in one area. CT has given the radiology community much more to consider.

The widespread adoption of multislice technologies has led to a boom in CT use in the emergency room. A retrospective study at the University of North Carolina at Chapel Hill found dramatic growth from 2000 to 2005: 51% in head CT exams; 72% in abdominal exams; 226% in chest scans. Miscellaneous use, including scans of the extremities and face, increased 132%. Cervical spine CT, which was used sparingly in 2000, rose 463% over the study period.

Meanwhile, technology marches on. Siemens released its dual-source CT commercially at the RSNA meeting. Toshiba announced plans to begin field testing a 256-slice CT in early 2007 at Johns Hopkins University. GE and Philips unveiled CT upgrades that dramatically reduce x-ray exposure during coronary CTA, opening the door to the use of this modality to screen patients at moderate risk of coronary artery disease.

The exhibit hall also played host to unorthodox ideas about CT. Koning plans to use flat-panel detectors to visualize breast cancer. Xoran has built flat panels into a head CT optimized for the ICU and operating room. NeuroLogica demonstrated a radiolucent head frame to expedite the OR use of its mobile CereTom CT, which was launched earlier this year for use in the ICU.

Market snapshot

The frenetic energy driving the CT community has been great for vendors. Last year was the best sales year in the history of CT. Revenue from the delivery of new CT units in the U.S. reached $1.5 billion, a 15% leap beyond the previous year on 3% growth in unit volume. Revenues during 2004 were themselves 8% greater than those of 2003. No one should expect this to continue, however.

Fear about reimbursements cuts has led to anxiety among vendors, but by midyear 2006 there was no sign of substantial trouble. CT revenues at that point topped $870 million. If they continue, the market for CT will rise this year by 13% over 2005. Some industry executives interviewed at the RSNA meeting were bullish that this might be a low estimate.

RSNA Exhibit floor

GE Healthcare launched two upgrades for its LightSpeed VCT: SnapShot Pulse to cut patient x-ray dose for coronary CT angiography by 70% or more, and Volume Shuttle to double the area covered during dynamic angiography and perfusion. Both change the scanner mode from a conventional helical acquisition to step-and-shoot mode, turning the x-ray beam off between axial acquisitions following each step of the patient through the gantry. (In November, less than two years after commercially releasing the product, the company shipped its 1000th VCT.)

The already compact BrightSpeed CT got smaller with the release of GE's Select series. The small footprint fits the constrained space often found in community hospitals and outpatient imaging centers, yet includes technologies developed for the firm's super-premium LightSpeed VCT. GE is positioning the system as a replacement for obsolete single-slice scanners.

Days before the meeting, GE and outpatient provider AmSurg signed agreements with the Cleveland Clinic to explore how CT colonography might evolve into an accepted screening tool for colon cancer. The deal calls for GE to provide 16-slice CTs, other equipment, engineering, and support; eRadiology, the teleradiology group within the Cleveland Clinic radiology division, to provide clinical expertise; and AmSurg to provide the outpatient facilities for conducting the exams.

Hitachi Medical Systems America boosted the appeal of its scanners through an alliance with TeraRecon, which provides Aquarius workstations and client-server image-management products in conjunction with HMSA sales of CT (as well as MR) products in North America. Earlier in the year, Hitachi extended its line of CT systems with the 16-slice CXR16. The midtier system features a 7.5 MHU x-ray tube, 72 kW generator, and reconstruction speeds up to 40 images per second.

Koning displayed a prototype CT optimized for breast imaging. At first glance, the Koning CT looks like a core-needle biopsy table, but a closer look reveals a miniature gantry beneath the patient table. The gantry houses a conebeam imaging chain that includes a 30 x 40-cm flat-panel detector with a scan time of about eight seconds. Conebeam algorithms reconstruct the data into a volumetric image of the breast.

Medis Medical Imaging Systems spotlighted QAngio CT, which quantifies cardiac and peripheral CTA studies to help detect arterial narrowing and assess the severity of abnormalities.

NeuroLogica showed its mobile CT, CereTom, in action, unveiling a prototype of a radiolucent cranial stabilization device designed to extend the system from the ICU bedside to the operating room. The headframe, developed in collaboration with ProMed Instruments of Germany, is designed to allow periodic rescanning during surgery.

Philips Medical Systems unveiled a work-in-progress update to its 64-slice Brilliance scanner that dramatically reduces patient radiation exposure while maintaining image quality. The step-and-shoot upgrade, now in beta testing and slated for commercial release in 3Q ’07, takes four single slices through the heart at specific times during the cardiac cycle. Engineers are developing an "arrhythmia rejection" algorithm that will command single-slice rescans in the event of an errant beat.

Philips sent CT everywhere with an optional adjunct that delivers CT processing to any networked location. Extended Brilliance Workspace (EBW) release 3.5, with its optional "Brilliance Everywhere," can hook into an iSite PACS workstation, EBW CT workstation, or home PC. Brilliance Workspace Portal 2.0, available in 2Q ’07, is a thin-client enterprise-wide server architecture that provides network-wide access to Brilliance Workspace software applications. Access is available through PCs without having to load the CT data set, turning PCs into primary image review stations or the means to share results remotely with referring physicians or specialists. Comprehensive tools designed to assess stroke accompanies improved software packages for vascular, lung, and colon applications.

Rendoscopy, a spin-off of the Institute for Clinical Radiology of the Grosshadern Hospital of the Ludwig-Maximilian-University Munich, peddled virtual colonoscopy software at a pavilion populated by German companies located across the aisle from Siemens Medical Solutions. Filters that remove noise from images promise dramatically reduced patient radiation exposure (as little as 1/14th of the dose found in conventional abdominal CT exams); 2D and 3D images of the anterior and posterior wall provide a look behind intestinal folds.

Siemens Medical Solutions launched its newly FDA-cleared dual-energy CT for the Somatom Definition CT. Leveraging the system's two x-ray sources to generate beams of differing power, the two simultaneously acquired spiral data sets allow direct subtraction of bone from soft tissue, liver imaging without enhancement by contrast media, evaluation of lung perfusion defects, visualization of cartilage, tendon, and ligaments, and differentiation between hard plaques and contrast agents.

Mushrooming data coming off 64-slice CT scans led Siemens to develop Sensation Web Selection, which the company framed as "Web-enabled CT." The new product affords instant access to CT volumetric data from any Internet-connected PC.

Toshiba America Medical Systems readied its 256-slice CT for the Johns Hopkins Heart Institute, which in February will become the first U.S. site to test-drive the beta system. Researchers there will have access for only a limited time, as the company will remove the device after radiology and cardiac protocols have been assessed.

Software advances address workflow and storage enhancements for the existing Aquilion platform, featuring the flagship Aquilion 64 and Aquilion 64 CFX for cardiac applications. The V3 software console release speeds scanning and data analysis. Automated PhaseXact software built into the SURECardio package automatically locates the optimal phase of the heartbeat for data acquisition. SUREPlaque, available on the Vital Images Vitrea workstation, visualizes and characterizes plaques likely to cause acute coronary events. New storage solutions, developed in partnership with McKesson, archive thin-slice data.

Xoran Technologies unveiled a work-in-progress CT scanner designed for use in the operating room. The scanner, dubbed xCAT, features a 30 x 40-cm flat panel and conebeam software for reconstructing 3D images of the brain at various points during surgery. Artifacts due to patient movement would not be an issue during the 40 seconds required for the U-arm gantry to rotate around an adult's head, as the patient would be anesthetized. Transparent lead shielding would control radiation scatter.