The bones in our bodies are in a perpetual state of restructure. Old bone is being replaced by new bone growth constantly, with the help of cells known as osteoclasts that reabsorb old bone and osteoblasts that make the old bones new again. Hormone changes within the body can cause a disruption in this delicate process; causing either cell group to become less efficient. As a result, bone loss conditions such as osteoporosis can develop. A bone density scan is a procedure that can help a physician determine whether such a bone loss is occurring in a patient's body.
Bone Density
DXA
A bone density scan is also known as a dual-energy x-ray absorptiometry, or DXA. According to the Stone Canyon Clinic of Southern Utah, there are two different types of bone density scan units. Peripheral DXAs are portable and often found on mobile units that visit community centers and local pharmacies. These devices are mostly suited for bone density tests that involve the appendages. Central DXAs are much larger and are most often utilized in hospitals and other health care facilities that do diagnostic testing. These units are capable of performing a full body scan.
Reasons for the Scan
A bone density scan is usually ordered if osteoporosis is suspected. A physician may also recommend the test if the patient has a pre-existing thyroid condition, is post-menopausal, has a history of fractures or smokes. The Mayo Clinic says patients who take prednisone, corticosteroids and anti-seizure medications may also be advised to have a bone density scan performed due to the close association between these types of drugs and bone loss.
How is it Performed?
During the bone density scan, the patient lies back on a soft table that is comfortably padded. The patient is expected to lie still for the duration of the test as the radiologist operates the equipment. A computerized imaging device passes over that patient and generates x-ray images of the patient's bones. The Foundation of Osteoporosis Research and Education says the test lasts approximately 40 minutes from start to finish. This includes preparation time.
The "Scores"
The results of a bone density scan are interpreted through "scores." The T score is a comparison between the patient's bone and the bone of an adolescent. Any T score above -1 is considered a healthy result. Osteoporosis is denoted by a -2.5. A bone density test score also consists of the Z score, which is a comparison of the patient's bone and others that are within the same age range. Small differences are normal in this test, with a significant difference suggesting that further bone testing should be performed. The University of California, San Francisco reports that bone density scan results are usually available within three to five business days.
Misconceptions
A bone density scan can be extremely useful in determining bone health; however, the test has limitations. For instance, a history of spinal surgery or bone deformities can render the test useless due to inconsistencies that can develop. According to Radiology Info.org, the test is also incapable of determining whether or not treatment for certain bone disorders are working effectively. In such instances, a physician may suggest a CT scan in lieu of a bone density scan.
Tags: bone density scan, bone density, density scan, bone density, bone loss, density scan, Bone Density
