Secondary Reference Material
Although BMD results provide a good indication of bone strength, the resultsof a bone density scan will not necessarilypredict whether you'll get a fracture.- Confirm they have complied with the recommendations listed above
- The menopausal status should be re-checked and whether a pregnancy test or question relating to possible pregnancy has been administered
- Subjects should be dressed in a hospital gown or scrubs, wearing only underpants and, if necessary, thin socks. A thin sheet may be placed over subjects for warmth.
- All radio-opaque objects should be removed from the scan area.
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Different DEXA systems have an automated placement/demarcation of the boundaries of the body regions. Although, readjustments may be required and the standardised protocol in Figure 3 can be adopted. The most common fracture sites in the osteoporotic spine is in the thoracic spine, just around your bra strap. For men, this is just below the bottom of your shoulder blades. DEXA reports never capture the thoracic spine for BMD recording because of the interference of our ribs and breast bone. In many jurisdictions, including the United States and Canada, women over the age of 65 and men over the age of 70 are encouraged to have a DEXA scan for preventative screening purposes. Your bone density test result also includes a Z-score that compares your bone density to what is normal in someone your age and body size. Among older adults low bone mineral density is common, so Z-scores can be misleading. A bone density scan, also called DEXA, uses an X-ray to measure the bone mineral content and density.
A bone density scan should be a part of your annual physical. Regardless of your age and sex, your primary doctor may recommend taking a preventative screening for bone mineral density if you have any of the following risk factors. Like the test for BMD in the spine, the generator in the DEXA scan machine will generate the photons that will pass through your hip and pelvis area and hit the target. The photon count will indicate the density of the bone mass in your femoral neck area. It is a good idea to have a baseline DEXA scan as you enter menopause. The results of this examination will give you an accurate record of the change of your bone density as you progress through menopause. It can also motivate you to maintain (or even improve) your bone density through exercise and nutrition, thereby reducing the chance that you will have take a pharmaceutical like Prolia, Fosamax or Forteo later in life. The long axis of the femoral diaphysis is aligned with the scanner as the patient lies supine and a positioning device that internally rotates the femur to elongate the femoral neck on the PA image. If the femur is effectively internally rotated the lesser trochanter should be barely, if at all, visible. Bone mineral density measurements are obtained using the femoral neck, greater trochanter, Wards area, intertrochanteric region, and total hip.
Once you have the baseline DEXA, there is no need to have another test for a number of years unless the baseline test identifies that you have low bone mass. Hi Darla. Thanks for pointing that out. We are aware of that but decided to stay with DEXA for the article because people still use that when they search on the internet. A C-arm with the x-ray source below the supine patient emits photons at two distinct energy levels specific for soft tissue and cortical bone. A collimator is situated between the patient and x-ray source to minimize scatter. The attenuations from these low and high-energy photon emissions are detected above the patient and are combined to create a planar image to assess bone mass per unit volume (g/cm), for example, bone mineral density (BMD). A T-score is anumber of standard deviations between the patients mean BMD and the mean of the populationcompared with reference populations matched in gender and race. The Z-score is the number of standard deviations above or below the meanof age-matched controls.
At Bupa we produce a wealth of free health information for you and your family. This is because we believe that trustworthy information is essential in helping you make better decisions about your health and wellbeing. The tools predict how likely it is youll have a fracture due to osteoporosis in the next 10 years. If it looks like your risk may be within a certain level, your doctor will advise you to have a DEXA scan. If youre pregnant or think you might be, it's important to let your doctor or radiographer know. You might not be able to have a DEXA scan because there is a risk that the radiation could harm your unborn baby. You will usually only be invited to have a DEXA scan if your doctor has assessed you as being at risk of fragility fractures. A fragility fracture is when your bones become weakened due to osteoporosis, so that even a minor bump or fall causes them to break. If you have symptoms of osteoporosis (brittle bones), your doctor may want you to have aDEXA scan. DEXA stands for dual energy X-ray absorptiometry. Are you a postmenopausal woman or man age 50 and older? Have you recently broken a bone? If you answered yes to both questions, you should talk to your doctor or other healthcare provider about getting a bone density test if youve never had one. Although the risk of osteoporosis is higher among older adults, especially women, anyone can get osteoporosis.
A DEXA scan produces more detailed images than a standard X-ray and helps to identify fragile bones before they break. A DEXA measures the bone density of spine, pelvis, lower arm and thigh. The procedure below removes the bone, the fat and the lean masses of the left arm from total mass, left total mass and left arm mass values and replaces it with the right arm values. A Peripheral DEXA evaluates the bone mineral density in the forearm, the heel bone (or calcaneus), the wrist and the hand. Some clinicians include this test during the examination. With most types of bone density tests, a person remains fully dressed, but you do need to make sure no buttons or zippers are in the way of the area to be scanned. The test usually takes less than 15 minutes. Bone density tests are non-invasive and painless. This means that no needles or instruments are placed through the skin or body. A central DXA uses very little radiation. You are actually exposed to 1015 times more radiation when you fly roundtrip between New York and San Francisco. Osteoporosis is the most common type of bone disease, which causes your bone tissue to become thin and week over time and leads to disabling fractures. If identified early, it can be easily treated and prevent potential fractures. Bone density scans also help the doctors to monitor the progress of osteoporosis treatment.
When Richard arrived for the procedure he had to complete a short intake form. It asked him if he had a history of fractures, took steroids in the past, and other relevant questions. Dual-energy x-ray absorptiometry (DEXA) has sustained a niche for measuring bone mineral density since its approval by the Food and Drug Administration (FDA) for clinical use in 1988. The Bone Mass Measurements act in 1998 solidified its validity in light of other diagnostic modalities such as chemical analysis, direct dissection and ashing, quantitative ultrasonography, and later on against CT/MRI images. DEXA is comparatively inexpensive with notably shorter scan times and radiation exposure compared to other imaging options, and there is a long-standing consensus regarding guidelines for interpreting DEXA images. You will need a referral from a GP or other health professional for a DEXA scan on the NHS. Your GP will refer you for one if theyve assessed you as being at risk of fragility fractures. Sometimes, you may already be seeing a hospital consultant if youve had a broken bone or are attending a fracture clinic. They may suggest a DEXA scan to check how fragile your bones are. When your physician wants to understand the health of your bones, the starting point is the DEXA scan.
They will schedule a DEXA examination at a medical imaging facility and review the results with you. An HHL greater than six centimetres for an individual over 60 and greater than four centimetres for someone under 60 suggests a new vertebral compression fracture. (4) Obesity can be a challenge for the DEXA equipment. First, the extra size can block the photons as they pass through the body and affect the score. Second, some manufacturers limit the size of the people who can take the test. One manufacturer has a weight restriction of 350 pounds. Wed love to hear what you think. Our short survey takes just a few minutes to complete and helps us to keep improving our health information. During your visit, the staff will not only measure your bone densitometry, they will carefully measure your height without your shoes on. Possibly of limited value or require modification of the technique or rescheduling of the examination in some situations, including: If the results indicate you have osteoporosis, osteopenia or low bone density, your physician uses these results to recommend an appropriate treatment protocol for you. Some software allows automated estimations of body composition for scans where the symmetry method was applied (e.
You do your research and learn that if you have osteoporosis, osteopenia or low bone density that therapeutic exercise needs to be part of your osteoporosis treatment program.Source: https://dapa-toolkit.mrc.ac.uk