Explanation of DXA results
Q: What is a T-score?
A:A T-score compares an adults results with the mean peak bone mass (thickness of bones) of a large number of normal females and males between the ages of 20-40.
Q: What is a Z score result?
A:A Z score compares the patient's score with their own age group; this is usually used in the diagnosis of the spine in children and adolescents. Their bone age should also be compared to their chronological age, by x –raying the bones of their non-dominant hand.
Q: Can you explain the T-score reading?
A: The IOS has broken up the scores in the osteopenia range to make it easier for people to know exactly where they are on the scale.
- Mild Osteopenia T-score = -1 to -1.49
- Mod Osteopenia T-score = -1.5 to -1.9
- Marked Osteopenia T-score = -2 to -2.49
- Osteoporosis T-score = Greater than -2.5
A fragility fracture (broken bone from a trip and fall from a standing position or less) is also considered to be Osteoporosis unless proved otherwise.
Research shows that most fractures (broken bones) occur within a T score of -1.5 to -2.49 which is the moderate to marked Osteopenia range.
All individual vertebrae levels should be looked at as well as both hip areas. It is recommended that a diagnosis should not be made on the total average of either the spine or the hip.
If a person has developed a hump on the back, an LVA (lateral Vertebral Assessment) of the thoracic spine (the area where the hump is) is usually recommended if available. If not available, a lateral x-ray of the spine is advised. This will show if the shape of the bones in this area are compressed due to an Osteoporosis fractures.
NOTE: Many people have arthritis and Osteophytes (extra bony spurs) which may have developed on the lumbar spine, which can give a false higher bone density reading. This would make your bones appear healthier than they actually are. A DXA scan usually only measures your lumbar spine (lower back = L1, L2, L3 and L4) and your hips, neck of femur and greater trochanter. The upper back (LVA) is usually not done unless specifically requested on the referral form.