Diagnosing Osteoporosis with Regular DXA/DEXA Bone Density Screening

When many hear the term “screening” their minds automatically go to cancer screening, as in breast cancer screening or prostate cancer screening.  But screening is effective for spotting and diagnosing a number of non-cancerous health conditions, including osteoporosis. Dual-energy X-ray absorptiometry (DXA or DEXA) bone density scanning is the most accurate method available for the diagnosis of osteoporosis, as well as an accurate estimator of fracture risk.

DXA scans use an enhanced form of X-ray technology to measure bone mineral density commonly in the spine or hip. This type of imaging exam can tell if a patient has normal bone density, low bone density (osteopenia) or osteoporosis, which leads to 1.5 million fractures annually in the United States. The lower a patient’s bone density, the greater the risk of breaking a bone.

UC San Francisco and the National Osteoporosis Foundation recommend women aged 65 and older and men aged 70 and older undergo regular bone density screening tests. Additionally, men or women who have broken a bone after age 50, women of menopausal age with risk factors, postmenopausal women under age 65 with risk factors and men aged 50 to 69 with risk factors are good candidates for DXA screening.  Physicians may be interested in ordering a bone density exam for patients who have an X-ray of a spine break or bone loss in the spine, back pain with a possible break in the spine, height loss of half an inch or more within one year, or total height loss of 1.5 inches from original height.

Those who test positively for low bone density should be screened every one to two years to ensure osteoporosis medication is working properly.

In addition to DXA, other options are available for measuring bone density. One alternative is the Quantitative Computed Tomography (QCT), invented at UCSF. QCT exams are able to measure bone density in patients who are very small or large, patients with degenerative disease of the back, and patients with prostate cancer who are being treated with Androgen deprivation therapy. Unlike DXA, which provides measurements in terms of area, QCT provides measurements in terms of volume by using cross-sectional CT images of the spine and hip to measure bone density.  The low-dose scan takes approximately 10 minutes.

Both DXA and QCT are available at a number of UCSF Imaging locations, including Montgomery StreetMission Bay and Mount Zion. To learn more information or schedule a DXA exam, speak to your referring physician or call (415) 353-3900.

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