Having A DEXA Scan? Start Here

PJ Hamel Health Guide November 23, 2008
  • Bone density: How thick/heavy/tightly packed with minerals your bones are. The more tightly packed—the denser your bones—the stronger they are, and the less likely to break. When bone density falls below a certain level, you have osteoporosis.

    DEXA scan: Dual Energy X-ray Absorptiometry, the most common, and one of the most accurate ways to measure bone density.

    If you’re any woman approaching age 65; a younger, post-menopausal women with osteoporosis risk factors (e.g., family history); or anyone with known osteoporosis risk factors, a DEXA scan may be in your near future.

    For all of you readers who’ve never had a DEXA scan and see one looming in your future, let me tell you: it’s about the easiest test you’ll ever have.

     

    Don't forget to put the appointment on your calendar: that's step #1!

     

    First, the preparation. Never mind the fasting for cholesterol, or the super-nasty prep for a colonoscopy. A DEXA scan requires only that you not wear perfume or lotion; and that your clothes should be without buttons, zippers, or snaps: think elastic-waist pants and a turtleneck.

     

    Whoops, forgot to take my work badge off. But this is the idea: elastic waist pants, pullover shirt.

     

    Easy, huh? If you don’t have sweatpants or equivalent, don’t worry; you can still have your DEXA. It just means you’ll have to take your clothes of and wear one of those stunning, open-backed hospital johnnies.

    Where will your DEXA scan be administered? Your hospital or clinic will almost certainly group DEXA scans with the other two common radiological tests: mammograms, and routine X-rays. If you’ve had either of those, you’ll know where to go for your DEXA.

     

    Radiology is usually where you'll have your DEXA scan.

     

    You’ll be taken into a room, asked to remove your shoes, and told to lie on an exam table.

     

    So far, so good, huh?

     

    The box-like scanner hovers over the area approximately where your knees will be. The person administering the scan will start with your hip, left hip if you’re right-handed, right hip if you’re left-handed. He or she will position you just so, your feet slightly spread, then tie your foot to anchor the hip (s)he’ll be scanning.

     

    My left foot is tied to a support so I don't move my leg.

     

    You’ll be asked to relax, breathe normally, and don’t move. The machine will move slowly overhead, scanning your hip; this takes no longer than 20 seconds or so. Don’t worry; unlike an MRI, you’re completely out in the open, and the scanner is absolutely silent.

     

    This is as close as the scanner gets; not like an MRI at all.

     

    Next, you’ll have four vertebrae in your spine scanned. For this, you’ll be asked to raise your legs and drape them over a box, so that your knees make a right angle. Then, same routine: hold still, breathe normally… 20 seconds or so, you’re done. End of story. Hop off the table, put on your shoes, you’re outta there.

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    Kind of relaxing, actually, to put your feet up.

     

    Later, you’ll get your DEXA results, probably at the follow-up visit with your physician. There’ll be a picture of your hip and spine, lots of numbers, and a graph showing you your bone density compared to that of others your age/sex.

    The main thing you’ll be discussing is your T-score. This is a number that compares your bones to a healthy young adult of the same sex, and then gives you a score. Zero is the healthy young adult score. For post-menopausal women, anything above –1 is considered normal. From –1.0 to –2.5, you’ve got osteopenia. Below –2.5, you’ve got osteoporosis. 

     

    Here's the kind of chart you might go over with your doctor. There's a separate page for each scan you had: hip, spine, and wrist, if you had your wrist done.

     

    Once you have the results of your first bone density test, it’s like having your first mammogram results: the doctor will use it as a baseline, to track whether/how fast your bones are thinning. Typically, the baseline test is followed by tests every other year. The tests may be done every year if there’s strong evidence your bones are thinning pretty quickly, and/or if you’re trying different things to stop osteopenia from turning into osteoporosis.

    There, that wasn’t so bad, was it? A DEXA scan is a piece of cake compared to a mammogram; keep that in mind if you’ve got your first DEXA scheduled soon.