DEXA (BMD) Bone Densitometry
Bone densitometry reduces the future risk of fractures. It is a type of procedure which is used to measure the calcium content of the bone. It involves exposing some parts of the body to a small amount of ionized radiation. It is a simple and non-invasive method.
Dexa Bone Densitometry
To estimate the bone mineral density in specific body parts or whole body, Dexa Bone Densitometry is used. (Especially done on post-menopausal women and older people)
What is Bone Densitometry?
To measure Bone Mass, Bone Densitometry is used. Bone mass is simply the weight of skeleton or masses of same specific regions. Spine, hips and arms are likely to fracture more if the bone mass decreases. The amount of bone you have in your skeleton determines how strong it is and how much trauma or force it can bear before it fractures. Bone densitometry measurements are useful in estimating the risk of fracture and to evaluate the result of treatment.
A Bone density test uses X-rays measure the amount of calcium in bones. This test is recommended for the people above age of fifty and post menopausal women. The test is also referred to as dual energy X-ray absorptiometry (DXA). It is an important test for osteoporosis also a common bone diseases type, tissue become thin and frail overtime due to osteoporosis.
What is Osteoporosis?
Osteoporosis is a metabolic disease affecting the skeleton, which is the reason for bony tissue reduction. As these tissues are reabsorbed or taken up by local cells. Bones gets weaken at the core, bones get less dense on the perimeter and cortical bones lose thickness. As bones become thinner, more porous and susceptible to fractures hindrance from osteoporosis arises.
Type of Osteoporosis
Type I or Post Menopausal Osteoporosis:
At this time the ovaries produce less estrogen (a female sex hormone). Due to the less estrogen bone mass drops below the maintenance density level leading to a high risk of fractures.
Type II or Age related osteoporosis:
It inflicts in men and women both (people more than 70 years of age). Older people have added risk of low bone mass because after 35 years of age bone density decreases. Older people are slightly vitamin D deficient they also have less ability to absorb calcium through their intestine. Less activity decreases bone strength as bone formation responds to physical stress.
Effect of Osteoporosis
If osteoporosis is asymptomatic it can go unnoticed.
Signs of reduction in bone mass:
- Lower back pain
- Loss of teeth and height over time often accompanied by a scooped posture.
- Minimal trauma fractures i.e. fractures occurring without the application of significant force. As bone density decrease, the risk of fractures increases.
Why the test is performed?
When the person has reached a certain age and preventive screening is necessary or the person is showing symptoms of osteoporosis in particular.
The following people should get preventive screenings of their bone mineral density (NIH)
- Women above 65 years of age are at high risk of osteoporosis
- Men above 70 years of age
- People taking glucocorticoid medications (those prescribed for autoimmune disorders) for two months or longer.
- Smokers or have a history of smoking
- Chronic Menopause
- Those who has eating disorder.
- Genetic history of osteoporosis.
- If person has a broken bone caused by regular or irregular.
- Regular alcohol consumption. (more than three drinks in a day)
- Rheumatoid arthritis
- Compression fractures in the spinal column.
Preparation for Bone mineral density test
Prior to the exam tell your doctor if you are pregnant. X-ray could harm your baby. (Slight possibility)
Don’t wear cloths with buttons, snaps or zip because metal can interfere in obtaining the X-ray images.
How the test is performed?
This exam is painless and requires no medications. The whole body or just some specific part has to lie down while the test is being performed.
Types of bone density scans:
1. Central DXA
This test involves lying on a table while an X-ray machine scans the hip, spine and other bones of your torso.
2. Peripheral DXA
This test is performed to examine the bones of your forearm, wrist, fingers or heel. This scan determines whether a patient needs central DXA or not. The test takes only a few minutes to get done.
Risks of a bone mineral density test
It involves X-rays so there is always a small chance of over exposure. However, radiation levels are very low the risk of radiation is lower than the risk of not detecting osteoporosis before you have a bone fracture.
The New York state department of health has reported that the radiation exposure during Bone density test is same as you will experience in a fight from New York to California.
Test results will be reviewed by your doctor. Your value will be compared to a healthy 30 years old. A score of zero is considered ideal.
The NIH offers the following guidelines for bone density normal: between 1 and -1.
Low bone mass: -1 to -2.5
Osteoporosis: -2.5 to lower
Severe osteoporosis: -2.5 or lower with bone fractures.