Diagnostic Imaging
November 1999

Tech Watch

CT heart calcium scoring could fuel imaging growth

Physicians and CT vendors stand to benefit from increasing interest in detecting early signs of atherosclerosis

By John C. Hayes

Fed by cardiac-gated spiral CT and asymptomatic but aging baby boomers looking for a way to assess their risk for heart disease, coronary artery calcium scoring could become a source of new business for radiologists.

Numerous clinics across the U.S. are developing calcium scoring programs, some of them relying on private-pay patients. In September, a startup company called Heartscore opened in Indianapolis, offering CT-based calcium scoring and lipid profiling. In its first week of operation, the clinic performed seven scans a day with its GE scanner. Business should grow as area physicians learn more about the service, said Dan Bailey, Heartscore president.

Direct marketing of calcium scoring has been tried before, with only modest success. Imatron, the manufacturer of electron-beam CT, established in 1993 the first of five clinics devoted to calcium scoring. EBCT has been promoted as a calcium scoring device based on its ability to capture the heart between beats during its fast 50 to 100-msec imaging time. This year, however, Imatron said it would sell off the clinics, which had become a drain on its revenues.

What’s different now is a growing body of research into the relationship between coronary calcium and atherosclerosis and the advent of calcium scoring systems that can be added to ordinary spiral CTs. The spiral scanners use EKG gating to select images taken when the heart is at rest. Although still not as fast as EBCT, the gated spiral systems are adequate for coronary calcium scoring, according to proponents. Two studies have suggested both the EBCT and CT spiral systems achieve equivalent results.

Bailey and others said wider publicity and the increasing availability of CT scoring systems will spread the popularity of the procedure.

“It will be like mammography,” he said. “The insurance companies will push back today, but two years from now they’ll have to provide coronary calcium screening as a covered benefit.”

That may be happening already. Dr. Winston S. Whitney, medical director for Hoag Imaging in Huntington Beach, CA, has been performing coronary calcium screening exams for the past year with a Siemens scanner, at the rate of about 40 per month. The clinic started out requiring that patients pay, but today finds that many insurers are covering the procedure. Hoag charges $400, but some clinics charge as much as $650, Whitney said.

Imatron has sold about 110 EBCT systems worldwide. Siemens has 15 spiral CT calcium scoring systems in place in the U.S. and GE has 30. A representative for Picker, which last year acquired Elscint, an early leader in spiral CT calcium scoring, said the company has about 50 systems installed worldwide, most of them in the U.S.

Despite the growing enthusiasm for calcium scoring, its clinical efficacy is still a matter of debate. A UCLA study presented at last year’s RSNA meeting found that patients with higher scores were more likely to experience a coronary event. But a study published in May in Circulation (25(20):2633-2638) found that calcium scoring didn’t provide any information not available by looking at traditional risk factors such as high cholesterol or hypertension.

That Circulation study added an element of controversy and deflated expectations for calcium scoring, Whitney said. Still, he and others believe that calcium scoring has value if only as an additional indication of possible atherosclerosis.

“It’s a screening test for asymptomatic patients,” Whitney said. “We use it to determine the aggressiveness with which risk factor modification—diet, exercise, and cholesterol-lowering medications—should be used. It is analogous to, but not a replacement for, cholesterol screening.”

One benefit of coronary calcium screening may be in emphasizing the need for lifestyle changes. In the UCLA study, for example, many high-scoring patients began cholesterol-lowering medications or started exercise programs.

“They may not be moved by high cholesterol numbers, but when they see that junk building up in the walls of their heart, that motivates them,” Bailey said.

Lung cancer agent distinguishes benign, malignant masses

Diatide has received approval from the Food and Drug Administration to begin selling NeoTect, a nuclear medicine imaging agent designed to help physicians distinguish benign from malignant lung masses. There are an estimated 170,000 new cases of lung cancer in the U.S. each year.

Although it is not considered an alternative to imaging and biopsy, NeoTect can help physicians determine whether a lung mass is malignant or benign, according to the company.

“Having conducted clinical trials with NeoTect, and having seen firsthand the results from this new approach, I believe NeoTect has the potential to become a valuable complement to chest x-rays and CT scans, which locate masses but cannot reliably determine malignancy,” said Dr. Jay E. Blum, chief of pulmonary medicine at Cigna Healthcare in Phoenix. Results of Blum’s NeoTect clinical trials were published in Chest in January.

Administered through an intravenous injection, NeoTect combines a small-molecule synthetic peptide with a molecule of technetium-99m. The peptide adheres to somatostatin receptors that are present in several types of cancer; the technetium-99m emits a gamma ray for detection.

Approval of NeoTect was based in part on clinical information from two multicenter trials involving 270 patients. The studies checked NeoTect images for concordance with histopathologic diagnosis and found NeoTect to have a sensitivity comparable to that reported for FDG-PET, according to Diatide.

Research led by Dr. Samuel S. Gambhir, a department chairman at the University of California, Los Angeles, concluded that scanning with NeoTect has the potential to save the U.S. healthcare system about $50 million a year by avoiding biopsies and unnecessary surgeries.

Diatide is using a similar strategy for a compound it is developing to treat lung and breast cancer. The compound consists of a targeting peptide similar to that in NeoTect but labeled with the therapeutic beta-emitting radioisotope, rhenium-188. Clinical studies were expected to begin this year.

Kodak joins move to Web distribution of medical images

Eastman Kodak has moved into the expanding market for supplying images to referring physicians with a new Web-based image distribution system. The company’s Distributed Medical Imaging System, comprising an image server, viewing software, and two low-cost medical imagers (Kodak 3600 and 1200), will allow referring physicians to access and print images and radiology reports via the Internet or an intranet.

The server accepts incoming requests, verifies security authorization, and displays images and reports retrieved from radiology information systems, digital imaging systems, and libraries. DICOM images and reports are displayed as Web pages, and images can be stored and viewed using JPEG compression. A remote printing feature eliminates physician waiting time for information sent to their offices by courier, and images can be printed on medical paper or film.

The system is distinctive in its ability to send both radiology reports and images, Kodak officials said. It will be marketed to radiology administrators and directors, who can use the server to “push” the images to physicians.

Low-cost image distribution product heads for market

By Kathy Kincade

A unique transmission protocol that distributes medical images at low cost across an enterprise is on the verge of commercial availability.

Stentor, a San Francisco-based start-up, has taken proprietary technology developed at the University of Pittsburgh’s Radiology Informatics Lab and turned it into a Web-based application service provider that can be downloaded by potential customers and used on standard PCs.

Formerly known as “dynamic transfer syntax,” iSyntax is a wavelet-based flexible representational data scheme that allows “just in time” delivery of electronic images via standard Ethernet lines to PCs anywhere in a hospital. When an image request is made, image data are sent to the requesting workstation in a manner that fits the requirements of the user and the resources of the network and viewing workstation.

“Our goal with this technology is to solve the problem of image distribution across the medical enterprise,” said Oran Muduroglu, Stentor president. “Many large PACS sites are still printing film for distribution outside of the radiology department.”

Rather than rely on compression or fetching techniques to make the images more manageable and speed transmission times, iSyntax sends and retrieves lower resolution versions of the images and allows the user to identify specific regions they want to see in higher resolution. This obviates the need for high-bandwidth networks and high-powered workstations and reduces end-user costs without sacrificing image quality or acquisition times, according to the company.

The Stentor approach is also unique in that iSyntax will be provided to customers as an application service provider rather than a hardware or software product. The program can be downloaded, installed on a hospital’s internal intranet server, and used for one month on a trial basis at no charge. A customer who decides to continue using it will then be billed on a per-use/per-image basis.

Stentor filed a 510(k) application with the Food and Drug Administration in August. Commercial release of the product is scheduled for March, following several more months of beta testing.

Portable system completes lower cost ultrasound line

Toshiba America Medical Systems has introduced a new portable ultrasound system. With a 9-inch monitor and built-in power unit, the JustVision 200 is lightweight and compact enough to be carried by hand through the hospital or office. It was requested by physicians because it can be carried from office to office, said Steve Sickles, senior director for Toshiba’ s ultrasound business unit.

A larger, cart-mounted version includes a 12-inch monitor and can accommodate recording devices such as printers and VCRs. Both models feature adjustable triple-frequency broadband transducers that allow sonographers to achieve optimal near- to far-field resolution in clinical situations. The systems include a dedicated wide-view small parts transducer, which offers image resolution with a total bandwidth range of 3 to 13 MHz.

The JustVision system, with a price tag of $25,000 to $30,000, rounds out Toshiba’ s low-end ultrasound line, but provides image quality rivaling mid-range systems, according to the company.

Companies advancing with radiation therapy for coronary stenosis

Two companies are reporting progress in bringing radiation-based therapy products for coronary artery stenosis to the U.S. market.

Nine-month follow-up results of a randomized clinical trial using a catheter-based gamma radiation ribbon found a 57% reduction in in-stent restenosis, Cordis executives said in September during an interventional cardiology meeting in Washington, DC. The results were included in a submission to the Food and Drug Administration for marketing approval.

Novoste reported in October that it has enrolled 1456 patients in its clinical trial to evaluate its gamma radiation brachytherapy system to prevent coronary restenosis following percutaneous transluminal coronary angioplasty or first-time stent placement.

The study included 252 patients with native coronary artery disease and in-stent restenosis.

In April, Novoste completed enrollment in its first pivotal clinical trial, which will support its FDA application in the second quarter of next year. A second clinical trial will support broader indications for its brachytherapy device, which is commercially available in Europe, Australia, and Israel.

Study affirms wide-field ultrasound

When given the option, sonographers will use extended field-of view-ultrasound (EFOV) techniques about 25% of the time, according to a six-month study conducted at Kingston General Hospital in Ontario and published in the Journal of Ultrasound in Medicine (1999;18:335-341). The study, apparently the first to look at real-time EOFV use in a variety of clinical situations, found that the technique is most popular for body wall, neck, scrotum, and musculoskeletal imaging, and least popular for breast, obstetric, endocavitary, and vascular imaging. At 26.5% of 1116 sonograms, EOFV was found to be slightly more popular than color Doppler sonography, which was used for 23.2% of 3256 sonograms. Siemens first introduced its SieScape EOFV technology in 1996 and now has about 175 systems installed in hospitals and clinics.