A new high-resolution imaging device, the XtremeCT, which measures both bone density and bone architecture, may have significant advantages over the current gold standard, dual-energy x-ray absorptiometry (DEXA), according to new research presented at the 27th Annual Meeting of the American Society for Bone and Mineral Research (ASBMR) in Nashville, Tennessee.

A three-dimensional peripheral quantitative-computed tomography (3D-pQCT) scanner, the XtremeCT yields highly magnified cross-sectional images of bones in living patients that can substitute for invasive surgical biopsies, at least in terms of evaluating bone architecture.

In just 3 to 4 minutes, the new scanner "allows us to measure the density of bones and also the architecture at the distal tibia and distal radius," researcher Pierre D. Delmas, MD, at Université Claude Bernard in Lyon, France, tells CIAOMed. "Because of the high resolution, we can measure not only the density [of bones], but also the number, separation, and thickness of the trabecular region," he explains, noting that the fragility of bones in osteoporosis also impairs the architecture of bones.

Thus, "this device could help us identify individuals at high risk of fractures in a more effective way than just doing DEXA," Dr. Delmas says.

Dr. Delmas and colleagues used the new scanner to examine the bones of 108 healthy, premenopausal  women and 148 postmenopausal women with osteoporosis or osteopenia.

In comparing the trabecular architecture of radial bones in postmenopausal osteopenic women with and without previous fracture, they found that the women with previous fractures exhibited significantly decreased trabecular density and increased trabecular separation compared to those without fractures. The XtremeCT also detected significant differences between osteoporotic and osteopenic bones and between the bones of premenopausal and postmenopausal women.

"These preliminary results suggest that in those women with osteopenia who had fractured, there was impairment in the structure of trabecular bone that did not exist in women who had the same density," Dr. Delmas says.

"These are very exciting data, because in recent years researchers in osteoporosis have developed a greater appreciation for the importance of bone quality in understanding fracture risk," writes ASBMR President-Elect Elizabeth Shane, MD, a professor of clinical medicine at Columbia University College of Physicians and Surgeons in New York City in a press release. "The XtremeCT clearly provides information on bone quality that is not available with any other technology," she notes.

While the expense of high-tech scanners such as the XtremeCT makes it unlikely that they will be used widely in a clinical setting, Dr. Shane points out that the machine may serve as a prototype for less expensive technologies in the future, as research focuses more on ways to measure bone quality as opposed to mass. "Such technologies, once [they are] more widely available and affordable, will be able to discriminate better among patients with normal and abnormal bone quality."

One important caveat, according to Dr. Shane, is that this machine does not permit researchers to view actual bone cells to assess remodeling activity, so "bone biopsies are still necessary for these types of analyses."

Reference

1. Boutroy S, Bouxsein ML, Munoz F, Delmas PD. Non-invasive measurement of trabecular architecture by 3D-pQCT discriminates osteopenic women with and without fractures. Presented at: 27th Annual Meeting of the American Society for Bone and Mineral Research; September 23-27, 2005; Nashville, Tenn. Abstract SA360.