Bone Densitometry (DXA)
Just as no physician would prescribe a medication for hypertension without first taking the patient’s blood pressure, the diagnosis and treatment of osteoporosis should begin with an objective, quantifiable measurement of the patient’s bone mass or bone density.Bone Densitometry uses an advanced technology called DXA (short for Dual-Energy X-ray Absorptiometry), which safely, accurately and painlessly measures bone density and the mineral content of bone.
How DXA Bone Densitometry Works
1. The Equipment: DXA is a fast, convenient and precise way to measure bone density to determine a woman's risk of developing osteoporosis.2. Bone Density Scan: Most common examination sites are the fracture-prone hip, spine and sometimes the forearm. Evaluation also includes measurement of height and weight, a thorough history, and risk assessment.
3. Data Analysis: Bone Mineral Density (BMD) is calculated and compared to normal BMD values, matched for age and sex, to confirm or exclude osteoporosis. A low BMD by DXA may predict the likelihood of developing osteoporosis and can help determine a treatment plan.
4. The Report: A report will be sent to your doctor that consists of your bone density measurements, a comparison of your results against an extensive database of young, normal bone density values, a comparison of your results against a database of other patients your age and sex, and recommendations for treatment and prevention.
Exam Preparation
Unless instructed otherwise, eat normally on the day of the exam, but avoid taking calcium supplements for at least 24 hours prior to your appointment.Wear loose, comfortable clothing. Sweat suits and other casual attire without zippers, buttons, grommets or any metal are preferred. Women will want to wear a sports bra without metal hooks or under wires. If you'd prefer, LIFESCAN Imaging will supply suitable clothing for your examination.
You should not have had a barium study, radioisotope injection, oral or intravenous contrast material from a CT scan or MRI within seven to ten days prior to your DXA test.
Bone Densitometry At A Glance
- 40% of postmenopausal women in the U. S. have osteopenia (low bone density). An additional 7 % have osteoporosis (Siris et al JAMA 2001).
- In 1995, osteoporosis-related fractures were associated with over 400,000 hospitalizations (Gelbach et al Osteoporosis International 2003), stressing the importance of early detection and appropriate prescription therapy.
- Bone mineral density (BMD) estimates the true mass of bone.
- BMD analysis is recommended for women between ages 50 and 65 with risk factors and for all women over the age of 65. In addition, men and women taking certain medications or having certain diseases should consider testing.
- By measuring BMD, it is possible to predict fracture risk in the same manner that measuring blood pressure can help predict the risk of stroke (Marshall et al BMJ 1996).
- Dual X-ray absorptiometry (DXA) is quick, painless and the preferred method to measure BMD.
- Osteoporosis has many available prescription and non-prescription treatment options once the diagnosis is made.
FREQUENTLY ASKED QUESTIONS
How long will the exam take?
The exam will last between 15 and 25 minutes.If I have a hip replacement, can I have a DXA?
If you have only one hip replacement, we will image the other hip. If you have two hip replacements, we will image your spine and forearm.If I have had spine surgery, can I have a DXA?
Yes, depending on the type of surgery you have had your test results will not be affected. If your spine surgery will affect your results, we will image your hip and forearm.Do I have to lie still during my exam?
Yes, any movement during the exam will cause image distortion and make it difficult to interpret your study.