Bone Mineral Densitometry
Bone Mineral Density (BMD)
Osteoporosis is a disease characterized by low bone mass and deterioration of bone tissue. This leads to increased bone fragility and risk of fracture, particularly of the hip, spine and wrist. Many patients are diagnosed with osteoporosis once they have suffered broken bones or a fracture. More than 1.4 million Canadians suffer from osteoporosis - one woman in every four women over the age of 50 suffers from osteoporosis while every one man in eight over the age of 50 has the disease.
Osteoporosis is diagnosed through Bone Mineral Density (BMD) tests using Densitometry (DXA). DXA can help detect osteoporosis and give indications as to whether a patient may develop it in the future.
Prior to bone densitometry, osteoporosis was detected through routine X-rays or a bone biopsy. However, with these methods, osteoporosis was rarely diagnosed before a fracture had occurred and a minimum of 25% of the bone's mass had already been lost. By that time, the disease is well advanced.
Why is DXA important?
DXA can help detect osteoporosis and give indications as to whether a patient may develop it in the future and help in the decision making process of preventing further bone loss. Prior to bone densitometry, osteoporosis was detected through routine X-rays or a bone biopsy. However, with these methods, osteoporosis was rarely diagnosed before a fracture had occurred and a minimum of 25% of the bone's mass had already been lost. By that time, the disease is well advanced.
Having a BMD test (DXA):
Bone densitometers (the machine that performs the test) are available on a limited basis in Ontario and patients who are suspected to be at high risk are generally given priority for this testing. Like any other diagnostic test, you must be referred to a radiologist by another physician.
When should you consider DXA:
When starting hormone therapy at the time of menopause (Estrogen is a key factor in maintaining bone density.
You are taking glucocorticoid medication.
You have recently had a fracture in which osteoporosis is suspected;
You already have osteoporosis and you and your physician are monitoring the effectiveness of the treatment.
You have been undergoing chemotherapy (especially for haematologic or breast cancer), where bone loss could be anticipated and needs to be confirmed.
You are a man with hypogonadism (low testosterone levels).
You and your physician have done a risk factor assessment and for a variety of reasons have determined that you are a high risk individual.
detects low bone density
will provide information to help create a treatment plan for osteoporosis
is helpful in monitoring rate of bone loss and determining success of treatment
Why is DXA better than an x-ray?
Between 25 and 30 per cent of bone loss has to occur before an x-ray shows the impact of bone loss and help lead to a diagnosis of osteoporosis.
Osteoporosis is treated through hormone therapy or other medications.