What is a DEXA scan?
By Deborah Condon
One in three women over the age of 50 will be affected by osteoporosis, according to the Irish Osteoporosis Society (IOS). However a simple scan that takes just 10 to 15 minutes, can predict the risk of fracture and help to identify patients who would benefit from taking preventative measures or treatment.
Osteoporosis is a condition in which there is a thinning of the bones, causing them to fracture (break) more easily. It is most commonly associated with older women, although men and younger people can also develop it. The DEXA (dual energy X-ray absorptiometry) scan provides a direct measurement of bone density. It is currently the most accurate and reliable means of assessing the strength of your bones and your risk of breaking a bone.
The scan is fast, accurate and painless and the dose of radiation used is extremely low. So what happens when you go for a scan, how much does it cost and who exactly needs to consider having one?
A DEXA scan takes just 10 - 15 minutes
Anyone, male or female, who displays one or more of the risk factors for osteoporosis, irrespective of age, should have a DEXA scan. This is because the earlier osteoporosis is identified, the more can be done to prevent it progressing. As a result, women in their 30s should consider having a scan, for comparison purposes in later years.
"Unlike their mothers, women today can take positive action to prevent the onset of osteoporosis or future bone fracture and can benefit from diagnosis and treatment. Today's treatments can help to prevent bone fracture by increasing bone density or slowing down and stopping bone loss", according to Dr Darragh Foley-Nolan, a consultant in rheumatology at Waterford Regional Hospital.
Specific risk factors for osteoporosis in women include a lack of oestrogen caused by, for example, an early menopause (before the age of 45) or an early hysterectomy (also before the age of 45). In men, having low levels of the make hormone, testosterone, is a risk factor.
However there are also a number of other risk factors for both women and men, including:
-Long-term use of high dose corticosteroid tablets, for conditions such as asthma and arthritis.
-A close family history of the disease, i.e. if your mother or father had it.
DEXA scans are usually carried out in a hospital, however some private clinics and GP surgeries also have scanners. When you are brought in for your scan, the scan technician will weigh you and measure your height. You will then be asked to lie on a padded examination table. You will remain fully clothed for the scan, only taking off your shoes. You will be asked to lie completely still while the scanner moves over the area of your body that is being scanned - most often the lower spine and hips.
Prior to the scan, you must inform the technician if you are pregnant (or think there is a chance that you are pregnant), if you have a metal implant in an area that may be scanned or if you have had any fractures in the past. You should also alert the technician if this is not your first scan, to allow your results to be compared.
The results of the scan will be made available immediately or very soon after, depending on where you have the it done. Your scan results will be given in the form of a T-score. This is where your results are compared to peak bone mass, which is the normal bone density found in healthy people aged between 23 and 35.
Your scan results will also be compared to the bone density of people of your own age (the Z-score), however osteoporosis will be clinically diagnosed based on your T-score.
A T-score value greater than -1 shows that your bone density level is normal and you do not have osteoporosis. A T-score value of between -1 and -2.5 indicates that you have osteopenia. This is the early stage of osteoporosis and is a warning that you must start taking care of your bones.
A T-score of below -2.5 meanwhile indicates osteoporosis. If you are found to have either osteoporosis or osteopenia, your doctor will make a number of recommendations, which may include medication and lifestyle changes such as quitting smoking, calcium and vitamin D supplements, a weight bearing exercise routine and reduced amounts of caffeinated drinks. You will also be asked to undergo a follow-up DEXA scan within 18 - 24 months, to assess any changes in bone health.
The Irish Osteoporosis Society recommends that you are scanned every two years after your initial scan. It also advises people to attend the same hospital for each scan if this is possible. This is because there are 10 different types of DEXA scanner and each one produces results in a different way, therefore for comparison purposes, it is more straightforward if you are rescanned by the same machine.
A DEXA scans costs between €80 and €100. If you are already a patient of a consultant and have a medical card, you may be able to avail of the scan free of charge, however the IOS warns that you may face a waiting list of up to a year for this.
"We recommend that people pay for this privately if at all possible. It is not a huge sum and the scan is so important", a spokesperson told irishhealth.com.
If you do pay privately, you can claim back tax relief for medical expenses. (You will require a Med 1 form from the Irish Revenue Commissioners.)
You may be able to claim some of the expenses back if you have private health insurance. Those with BUPA insurance can apply the cost of their scan to their annual excess.
Members of the VHI's Healthsteps schemes can also claim back part or all of the cost of the scan. However bone density scans are not covered under any of the VHI's hospital plans.
With VIVAS Health, a DEXA scan is categorised as 'health screening' - under its day to day plan, you can claim back €50 for one screening per year, i.e. if you claim for a different type of screening in one calendar year, you will not be able to claim back anything on your DEXA scan.
If you have private health insurance, check your membership booklet for details.
The Irish Osteoporosis Society can be contacted at (01) 677 4267 or firstname.lastname@example.org
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