Bone Densitometry is a test similar to an x-ray used to measure bone density and mineral content. It can also be referred to as dual-energy x-ray absorptiometry (DXA). The text is often used at Gheyenne OBGYN to measure bone loss and diagnose osteoporosis, meaning the bones are fragile and susceptible to future fracture. Generally, the bones of the lower spine (lumbar), pelvic area, and lower arm will be scanned during the test.
Bone densitometry is noninvasive and involved two x-rays; one of your hip, and one of your lower spine. The data is analyzed with a computer program, and your risk of fracture is calculated. You may be asked to wear a gown simply because any metal can interfere with the test including jewelry, zippers, and buttons. You will lie on your back and a scanner will pass over you. The test is very quick, usually requiring only 10-30 minutes and you are exposed to minimal radiation.
Bone density tests are most often recommended for older women who are at higher risk of osteoporosis, since a drop-in estrogen can cause a decrease in bone density. However, the test is also recommended if you have lost height, fractured a bone, taken certain drugs, received a transplant, or had a drop-in hormone levels.
Your bone density is measured in the form of a T-score and a Z-score. Your T-score is simply the number of standard deviations that you are above or below average. A T-score of -1 and above is considered average. A score between -1 and -2.5 standard deviations away from normal is a sign of osteopenia which leads to osteoporosis. A score below -2.5 means that your bone density is very low and likely already have osteoporosis. Your Z-score will tell you how many standard deviations your bone density is above or below what’s expected for a person of your weight, sex, age, and race.