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What is Bone Mineral Density (BMD)?

Bone consists of a protein (collagen) structure covered by bone mineral (hydroxyapatite).

Bone density, and therefore bone strength, depends largely upon the amount of bone mineral present.

The most common reason for low bone mineral density is the osteoporosis associated with ageing (see below) but changes in BMD may occur in many other bone diseases and diseases that affect the bones secondarily. Measurement of BMD may be valuable to detect the disease, to demonstrate the need for treatment and to assess response to treatment.

A balanced diet, some level of mobility and exercise, and a balance of natural hormones are necessary to maintain bone mineral density. Changes to these may lead to an abnormality (usually a loss) of BMD.

What is Osteoporosis?

Osteoporosis is “thinning” of the bones due to loss of both bone mineral and protein structure. It most commonly occurs as part of ageing and is like the progressive rusting that may weaken a steel structure. In men, the loss begins in early adulthood and continues steadily. In women, bone mineral density is usually maintained at a healthy level until close to menopause. It can fall sharply for a few years after menopause and may steadily decline with age.

Various factors may cause or speed osteoporosis: diet, smoking and treatment for a variety of unrelated diseases. Post-menopausal women are concerned by osteoporosis although it occurs in both sexes. It may be specific to one area, i.e. hip, or it may affect the whole skeleton. The presence of osteoporosis may be detected by BMD measurement even when conventional X-rays are normal. Osteoporotic bone is brittle and at increased risk of fracture.

People are not equally at risk of developing osteoporosis.

How is BMD measured?

BMD is measured very precisely by a computerized X-ray scanning method. Measurement is made at the lower (lumbar) spine and at the hip (femoral neck) because these are sites where fracture is likely to occur spontaneously or in response to minor trauma if BMD is lost and the bone weakened.

Where do I go?

Your procedure will take place at the Riverside Campus. The bone density service is located within the Radiology Department on the main level. From the elevators, turn left and follow the signs to the Radiology reception.

Where do I park?

Parking is available in the two parking lots: one is located outside the main entrance and the other is located outside the main entrance to the Riverside Professional Centre at 1919 Riverside Drive.

Are any special preparations necessary?

To save time and ensure your comfort during this procedure, we ask that you wear loose, comfortable clothing without metal (for example, a sweat suit). Metal from underwire bras, zippers, buttons or snaps affects the information we obtain. If your schedule requires that you arrive in more formal attire, we encourage you to bring clothes that meet the above requirements.

Who will perform the procedure?

A specially trained technologist will perform the procedure under the direction of a specialist medical doctor.

What will happen to me?

For the lower back measurement, the technologist will position you on the scanning table with your legs elevated but supported so that your back is as flat as possible against the table.

For the hip measurement, you will be positioned flat on your back, with your legs extended, with one hip rotated inwards. Correct positioning is crucial particularly if it needs to be repeated later. The X-ray source will scan automatically across your lower abdomen and pelvis. It will not come close to you.

The process will take 15–20 minutes.

A technologist will be in the room with you for the majority of the time to operate the equipment and to attend to your needs and answer your questions. He or she may leave the room briefly but there will always be someone close at hand. He or she will also ask you some questions to obtain a full medical history.

You will not be given any medication so you will be able to go home immediately after the test.

Will there be any after-effects?

You should not expect any after-effects from the procedure. The amount of radiation involved is less than half that of a chest X-ray and a small fraction of what you are exposed to from natural radiation in the environment each year.

How and when will I know the results?

A specialist physician will examine your results and send a written report to the doctor who ordered the test. This takes about one week.

Will it be necessary for me have this procedure done again and how often?

In some patients, a single measurement of BMD is enough to establish the state of the bones. Others, particularly those requiring treatment, may need follow-up studies to monitor disease progression or response to treatment. Follow-up studies are usually done at intervals of one year or longer because changes in bones happen slowly.

Still have questions?

If you have any questions or concerns that are not answered, please call 613-761-4831, option 8, or ask our staff when you come for your test. We are here for you — patient care is our first concern.

Last updated on: November 17th, 2016