Bone density scanning, also called bone densitometry, is an enhanced form of x-ray technology that is used to measure bone loss in the body.
Bone Mineral Density (BMD) measurement is most often performed on the lower spine and hips. In children and some adults, the whole body is sometimes scanned. With the advancement of CT technology in the past few years, a CT scan with special software is being used to accurately diagnose or monitor low bone mass (QCT).
DXA and QCT are most often used to diagnose osteoporosis, a condition that often affects women after menopause but may also be found in men and rarely in children. Osteoporosis involves a gradual loss of calcium, as well as structural changes, causing the bones to become thinner, more fragile and more likely to break.
These techniques are also effective in tracking the effects of treatment for osteoporosis and other conditions that cause bone loss.
BMD measurements can also assess an individual’s risk for developing fractures. The risk of fracture is affected by age, body weight, history of prior fracture, family history of osteoporotic fractures and life style issues such as cigarette smoking and excessive alcohol consumption. These factors are taken into consideration when deciding if a patient needs therapy.
At the hip, QCT produces DXA-equivalent measurements compatible with FRAX®. At the spine QCT is unique and different from DXA in that QCT measures trabecular bone exclusive from cortical bone thus avoiding complexities which can confound the interpretation of DXA measurements such as those associated with degenerative changes, scoliosis, extra-osseous calcifications, and obesity.
Studies have shown that 55 to 90% of osteoporosis-related fractures occur in individuals that would not be diagnosed with osteoporosis based on a DXA BMD test.
Bone density testing is strongly recommended if you:
- Are a post-menopausal woman and not taking estrogen.
- Have a personal or maternal history of hip fracture or smoking.
- Are a post-menopausal woman who is tall (over 5 feet 7 inches) or thin (less than 125 pounds).
- Are a man with clinical conditions associated with bone loss.
- Use medications that are known to cause bone loss, including corticosteroids such as Prednisone, various anti-seizure medications such as Dilantin and certain barbiturates, or high-dose thyroid replacement drugs.
- Have type 1 (formerly called juvenile or insulin-dependent) diabetes, liver disease, kidney disease or a family history of osteoporosis.
- Have high bone turnover, which shows up in the form of excessive collagen in urine samples.
- Have a thyroid condition, such as hyperthyroidism.
- Have a parathyroid condition, such as hyperparathyroidism.
- Have experienced a fracture after only mild trauma.
- Have had x-ray evidence of vertebral fracture or other signs of osteoporosis.
The Lateral Vertebral Assessment (LVA), an examination of the spine to screen for vertebral fractures that is performed on the QCT or DXA machines, may be recommended for older patients, especially if:
- They have lost more than an inch of height.
- Have unexplained back pain.
- If a DXA scan gives borderline readings.
- High sensitivity of QCT spine measurements which are not affected by spine degeneration and other conditions that DXA cannot address:
- Aortic calcification.
- DXA-equivalent hip measurements with our revolutionary new technology that allows DXA-equivalent hip BMD measurements with a CT scanner.