Bone Density Screening Test - Ultra Sound VS DEXA
Bone density testing is used to evaluate risk of osteoporosis. Osteoporosis is a disease where bones become fragile and more likely to break or fracture due to loss of bone density. Any bone can fracture. As we age, a greater concern for fractures of the hip and spine may be warranted. A hip fracture may require major surgery that can cause prolonged disability and even death. Spinal fractures can result in loss of height, severe back pain, and deformation.
For additional information on osteoporosis, including risk factors, prevention and treatment, please visit the National Institutes of Health webpage entitled: Osteoporosis and Related Bone Diseases
What equipment is used for the test?
In the past, screening for osteoporosis has been performed only through a relatively costly and time consuming procedure called Dual-Energy X-Ray (DEXA). With the advent of ultrasound, it is now possible to measure bone density with a small, portable ultrasound unit designed exclusively for bone density testing.
Some equipment used by affiliated companies use the highly advanced QUS-2. These systems require about 10 minutes and cost approximately $45. Some insurance companies pay for these test.
The QUS-2 is designed with round knobs called transducers that will move around the heel very gently. It is something like having a massage. The scan takes less than 2 minutes. The QUS-2 Calcaneal ultrasound unit assesses the quality of the calcaneus (heel) by sending a form of acoustic energy, known as ultrasound, from one transducer to another through the heel bone. By analyzing the ultrasound that tranverses the heal, the QUS-2 determines the patient’s calcaneal Broadband Ultrasound Attenuation (BUA) that can be compared to the results from a reference population. The result is expressed in standard deviations called the T-score.
QUS-2 test results are generally recognized as comparable to DEXA.
How does this test unit work?
QUS-2 measures the bone density of the heel. The heel is used because its structure provides measurements comparable to DEXA measurements of the hip and spine.
Using high frequency sound waves, the QUS-2 measures both the speed of sound and broadband ultrasound attenuation. This means that it analysis the density of the bone by measuring both how fast sound travels through it, and how much of the sound reaches the other side.
Ultrasound does not travel through air. If you’ve had an ultrasound test before, it is likely that a heavy gel was used between the sensor and the body. The gel works as an acoustic coupling through which the sound waves travel. The QUS-2 does not use water but has a unique system where the machine transducers search for the optimal place on the heal for the scan to take place.
What does the test feel like?
The procedure is completely non-invasive and painless.. The QUS-2 feels like a gentle message.
Because the equipment requires direct skin contact with the back heel, you must remove any foot coverings such as pantyhose, socks & shoes.
When do I get my results?
Printed test results are presented to each client for their historical records and to discuss with their doctor.
QUS-2 measures how fast the sound travels through the heel bone and how much of the sound reaches the other side, are combined into a single index called the Stiffness Index. The Stiffness Index is an expression of bone quality relating to density, structure and strength.
The Stiffness Index is then used to create the T-score:
- T-score: compares your bone quality, expressed as the “stiffness index”, to that of a healthy young adult when bone quality is at is peak, usually at about age 30. T-scores are represented as standard deviations from the average, and can be either a + (positive) or a – (negative) number.
A print out is given at the time of service.
How is the T-score interpreted?
The T-score indicates current risk for fracture as compared to a healthy young adult.
- The “healthy young adult” used for the reference model would obtain a T-score of 0.0. If the score is + (plus), then you are above average. If the score is – (minus), then you are below average. Remember, this is a comparison to peak bone quality.
- A T-score higher than 0.0 indicates less risk than that of the reference model.
- A T-score lower than 0.0 indicates greater risk than that of the reference model.
Risk is defined as follows:
- A score higher than -1.0 indicates low risk.
- A score between -1.0 and -2.4 indicates intermediate risk or osteopenea.
- A score lower than -2.5 indicates high risk or osteoporosis.
Dietary Guidelines for Prevention of Osteoporosis are available to assist you in maintaining good bone health.
