Wednesday, May 30, 2012

Osteoporosis - Diagnosis

Bone density scan
A bone density scan measures the density of bone in a person. The lower the density of a bone the higher the risk of fractures. A bone density test, along with a patient's medical history, is a useful aid in evaluating the probability of a fracture and whether any preventative treatment is needed. A bone density scan has the advantage of being painless and exposing the patient to only a small amount of radiation.

Central DXA measures the bone mineral density at the hip, upper thigh bone (femoral neck), and spine.

Click the icon to see an image of a hip fracture.

Other Tests. Other tests may be used, but they are not usually as accurate as DXA. They include ultrasound techniques, DXA of the wrist, heels, fingers, or leg (peripheral DXA) and quantitative computed tomography (QCT) scan.

Screening tests using these technologies are sometimes given at health fairs or other non-medical settings. These screening tests typically measure peripheral bone density in the heels, fingers, or leg bones. The results of these tests may vary from DXA measurements of spine and hip. While these peripheral tests may help indicate who requires further BMD testing, a central DXA test is required to diagnose osteoporosis and to monitor treatment response.

Diagnosing Osteoporosis and Predicting the Risk for Fracture

Osteoporosis is diagnosed when bone density has decreased to the point where fractures will happen with mild stress, the so-called fracture threshold. This is determined by measuring bone density and comparing the results with the norm, which is defined as the average bone mineral density in the hipbones of a healthy 30-year-old adult.

The doctor then uses this comparison to determine the standard deviation (SD) from this norm. Standard deviation results are given as Z and T scores:


Review Date: 10/21/2010
Reviewed By: Harvey Simon, MD, Editor-in-Chief, Associate Professor of Medicine, Harvard Medical School; Physician, Massachusetts General Hospital. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.

A.D.A.M., Inc. is accredited by URAC, also known as the American Accreditation HealthCare Commission (www.urac.org)

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