Market growth for densitometers depends on primary-care practices

Manufacturers of bone density machines are enjoying steady and healthy business from hospitals, according to industry sources. Radiology departments and women's imaging centers are adding second and even third central dual x-ray absorptiometry (DXA) units, while replacing older technology with newer iterations. The push for central DXA in the future, however, will come from primary-care practitioners.

GE Healthcare reported that revenues from densitometry were up 36% in the second quarter of 2003 compared with Q2 2002. Bone densitometry sales for Hologic were up 15% in 2003.

Central DXA can continue to look forward to double-digit annual growth as primary-care practitioners recognize its clinical and financial returns. Reimbursement is strong for both bone density measurement and vertebral assessment: $140 a scan for overall bone density and $70 for the vertebral column. And the target patient population, predominantly menopausal women, is large and growing. According to the National Osteoporosis Foundation, nearly 44 million people in the U.S. are at risk for osteoporosis.

As a result, primary-care practices can break even on bone densitometry by scanning about 10 patients a month, and a typical practice may see between 15 and 20 menopausal women in a day, said Eric Von Stetten, Ph.D., vice president and general manager of osteoporosis assessment and mini C-arm imaging for Hologic.

Yet only about 10% of 250,000 primary-care practices in the U.S. have a bone density machine. Not all such practices will end up buying the instruments, but a significant percentage can and should, he said.

As an indicator of the growth potential for central DXA, Von Stetten noted that the number of reimbursements for yearly densitometry exams still lags far behind the number for mammograms. But the gap is closing. There were six times as many reimbursed mammograms as bone density tests in 1996. The difference between mammography and bone densitometry was 20:1 a few years earlier. Eventually, the ratio will be about 1:1, he said.

Central DXA is easy to install in primary care. All a practice needs is an outlay of $85,000 and an 8 x 8-foot room. There's no need for special radiation shielding, and, because the instruments are automated, most states don't require certification of technologists, Von Stetten said.

Manufacturers nevertheless are adding features for the primary-care setting. At last year's RSNA meeting, GE introduced Prodigy Advance, which has a direct digital detector array, TruView image reconstruction (to eliminate magnification and distortion effects from fanbeam densitometry), QuickView 10-second anteroposterior spine and femur image acquisition, and Composer automated reporting. Prodigy Advance includes such office features as a washable pad and patient weight allowance up to 350 pounds.

Also shown by GE at the RSNA meeting were the Lunar DPX Duo bone densitometer that doubles as a standard examination table and the Dexter handheld software option that provides a full-screen display of exam results, including images and graphs, and a soft-touch keyboard or handwriting recognition for recording physicians' comments.

Hologic's Discovery, which was introduced in late 2002 as a replacement for the Delphi product line, incorporates the same core densitometry elements as the earlier instrument: a large number of detectors in a linear array for rapid, single-direction image acquisition; OpenPass technology for single-sweep scanning; and Instant Vertebral Assessment for a 10-second, high-resolution, single-energy image of the spine at only 1% of the radiation dose of standard radiographic examinations, according to the company.

Discovery also carries over from Delphi the Internal Reference System, which increases the accuracy and stability of measurements by automatically assessing bone density on a pixel-by-pixel basis, calibrating a patient's bone density measurements to an established standard, and compensating for drift in the x-ray system, detectors, or other electronic components. New to Discovery are CADfx, a computer-aided detection feature for automatically classifying spine fractures, and Express Exam, a fully automated examination procedure.

Especially attractive for the primary-care office is Discovery's flexible modular design, which can be configured in six different ways. And wireless electronic reporting, which sends soft-copy images to a tablet PC that has been networked to the scanner, allows physicians to review bone density scans and complete their reporting at home.

At the Journees Francaises de Radiologie 2003 meeting in Paris, Hologic introduced the Explorer, a low-cost fanbeam densitometry system intended primarily for markets outside the U.S. with lower reimbursements for osteoporosis screening and diagnosis. Explorer offers OnePass fanbeam technology and the Internal Reference System at prices similar to those of older rectilinear scanning systems. It replaces the Delphi QDR 4000, Hologic's last rectilinear system.

Future growth of bone density assessment most likely will parallel an increase in awareness of osteoporosis risk by patients and their physicians.

"When women turn 40, they know they will get a mammogram. When they go through menopause, it's not clear women or their doctors know they need a bone density test. They don't necessarily know when and aren't quite sure how to get one. And their doctors haven't been very forward," Von Stetten said. "But that's changing. Someday, everybody will know that they need a bone density scan at age 50, or maybe 45."