Bone strength is one part of your overall fitness and health when growing older. To diagnose bone quality, a type of DEXA scan-also known as DXA bone density test-conducts studies which include identifying risks from fracture. As the article focuses on DEXA scan basics: purpose, steps in conducting one, and possible interpretations of their findings.
DEXA stands for dual-energy x-ray absorptiometry,it is a form of medical imaging whose purpose is to help measure the level of bone density. Using small doses of X-rays, a DEXA scan can check the level of calcium as well as mineral content within one’s bones and the strength or even thickness that makes them stronger than others with poor bone density – less prone to fractures.
Role of Bone Density
Bone density represents the mass of minerals, primarily calcium in a given volume of bone. Optimal bone density is required to maintain the strength and integrity of the skeleton. When bone density is reduced, bones become weaker and more susceptible to fractures, greatly impairing the individual’s quality of life and independence.
Bone Density Disorders
These diseases cause bones to become weaker and more likely to break:
Osteopenia
Osteopenia is a condition characterized by lower than normal bone density. It serves as a precursor to more severe bone disorders and indicates an increased risk of developing osteoporosis. Individuals with osteopenia should monitor their bone health closely to prevent further bone loss.
Osteoporosis
Osteoporosis is a degenerative condition that makes bones extremely thin and brittle. The disease mostly strikes older adults, especially women who are over 65 years old. Osteoporosis highly increases the likelihood of fractures in the hips, spine, and wrists. These fractures cause extreme medical complications and a loss of mobility.
Applications of a Bone Density Scan
A DEXA scan is used for several purposes:
- Diagnosis of Osteopenia and Osteoporosis: Detecting reduced bone mass and the extent of bone loss.
- Prediction of Fracture Risk: Probability of future fractures given current bone density.
- Treatment Monitoring: Follow-up to see how treatments designed to build up bone or reduce further loss are working.
When to have a Bone Density Scan
Bone density scans are prescribed to people who have risk factors for the loss of bone density. The population recommendation is for women older than 65 years; however, the following could also be candidates for undergoing some sort of tests:
- People with a very low body weight.
- Those who, after age 50, have developed fractures.
- Those people, after a year, who lost considerable height.
- Those family members who have a positive family history of osteoporosis.
Risk Factors for Low Bone Density
Some of the factors that cause reduced bone density include:
- A lack of exercise weakens the bones.
- Smoking or excessive alcohol intake has a detrimental effect on bones.
- Poor intake of calcium and vitamin D lowers the density of bones.
- People with diabetes and rheumatoid arthritis have a lower bone density.
- Advanced age and female sex are risk factors for bone density loss.
Procedure of a Bone Density Scan
There are two major types of DEXA scans: central DEXA and peripheral DEXA (p-DEXA).
Central DEXA Scan
The central DEXA scan is the most sensitive and precise method to assess bone density. It commonly concentrates on the lower spine, hips, wrist, or the whole body. The procedure includes the following steps:
- Positioning: Patients typically lie down on a cushioned table; patients are expected to wear conventional attire without wearing metallic fasteners.
- Scanning: A scanner passes along the areas scanned with low dosage of X-ray emanating in two different energies levels. Concomitantly, another scanner may also pass underneath.
- Image Processing: This computer combines all the data provided by the two scanners and later forms images in order for one health care professional to review.
- Duration: This whole procedure takes about 10 to 30 minutes, and the findings can be expected within a few days.
Peripheral DEXA scan
This peripheral DEXA scan often targets bones located peripherally, such as the wrist, hand, or foot. It is a portable scan that is conducted at different places, such as clinics or pharmacies. The process is relatively easier and quicker as well:
- Application: the patient places the respective body part into the scanning device.
- Scanning: The scan only takes a few minutes and provides immediate results.
- Purpose: While p-DEXA scans give some information regarding fracture risk, they are not as rich in data as central DEXA scans. In case high risk is diagnosed, a central DEXA scan is advised.
Preparation for the Test
Preparation for a DEXA scan requires minimal adjustment:
- Patients are advised to discontinue calcium supplements 24 to 48 hours before the test.
- Loose-fitting clothes without metal parts are a must. Jewelry and other metal items should be removed to avoid interference with the scan.
- Any recent imaging tests should be communicated to the healthcare provider, as a DEXA scan should not be done within 24 hours of other X-ray-based procedures.
Risks and Safety
DEXA scans are safe, using minimal levels of radiation. However, some precautions are required:
- The test is not advisable for pregnant women as it may pose a risk to the developing fetus.
- The radiation dose is minimal, but it should be avoided if possible during pregnancy.
Generally, the advantages of early detection and prevention of severe bone conditions outweigh the minor risks associated with the test.
Interpretation of Results
Bone density results from a DEXA scan are usually expressed as T-scores and Z-scores.
T-Score
The T-score compares an individual’s bone density to that of a healthy young adult of the same sex. It is mainly used for postmenopausal women and men aged 50 and older.
- Normal: T-score of -1.0 or higher.
- Osteopenia: T-score between -1.0 and -2.5.
- Osteoporosis: T-score of -2.5 or lower.
Z-Score
The Z-score compares bone density to that at age, weight, gender, and race. It is designed for premenopausal females, males under the age of 50, and children. A higher score shows higher bone density; a lower score indicates a better chance of fracture.
Follow-Up and Treatment Recommendations
When a DEXA scan reveals low bone density, healthcare providers may suggest different kinds of interventions to prevent further bone loss:
- Weight-bearing and strength training enhance bone strength.
- Increase the levels of calcium and vitamin D either through diet or supplements to strengthen the bones.
- The patient may be put on prescription medications to improve their bone density to reduce the chance of fractures.
- Follow-up scans are recommended according to individual risk profile, which includes two-yearly screening for high-risk people, three to five-year screening for moderate-risk, and ten to fifteen-year screenings for low-risk.
Other Bone Health Tests
At times, more tests are required to diagnose some conditions or check the effectiveness of treatment. Some of these include:
- Calcium Blood Test: It measures the level of calcium in the blood.
- Vitamin D Test: Assesses vitamin D status, crucial for bone health.
- Hormone Tests: Evaluates hormone levels that influence bone density.
Limitations of DEXA Scans
While DEXA scans are highly effective, certain conditions can affect their accuracy:
- Spinal Surgery or Deformities: These can interfere with spinal bone density measurements.
- Fractures or Arthritis: Existing fractures or arthritis in the spine may skew results.
Conclusion
A DEXA scan is a very important tool in assessing bone health, enabling early detection of conditions such as osteopenia and osteoporosis. By measuring bone density, doctors can predict fracture risks and implement preventive measures to maintain skeletal strength.
Given its safety and effectiveness, a DEXA scan is recommended for individuals at higher risk of bone density loss. Regular bone density assessments, in conjunction with appropriate lifestyle
