A variety of imaging studies are available for noninvasive measurement of a patient's bone density.
Parameters:
(1) radiation dose
(2) accuracy (false positives, false negatives, artifacts)
(3) cost
(4) ease and convenience, including operator skill required
(5) bone site measured
(6) responsiveness of site to antiresorptive therapy
Methods available:
(1) single energy X-ray absorptiometry (SEXA)
(2) dual energy X-ray absorptiometry (DEXA)
(3) ultrasonography (US)
(4) quantitative computed tomography (CT)
Method |
Site |
Radiation Dose |
Accuracy |
Cost |
Ease |
Responsive
|
SEXA |
forearm |
1 |
2-3 |
1 |
2 |
No |
SEXA |
heel |
1 |
2-3 |
1 |
2 |
No |
DEXA |
lumbar spine |
1 |
2-3 |
2 |
1 |
Yes |
DEXA |
proximal femur |
1 |
2 |
2 |
1 |
Yes |
DEXA |
whole body |
2 |
3 |
3 |
1 |
No |
US |
finger |
0 |
1-2 |
1 |
3 |
No |
US |
heel |
0 |
1-2 |
1 |
3 |
No |
US |
tibia or patella |
0 |
1-2 |
1 |
3 |
No |
CT |
spine |
3 |
2 |
3 |
1 |
Yes |
CT |
forearm |
3 |
3 |
2 |
2 |
No |
where:
• 0 = none, 3 = high
• Responsive indicates that the bone density reading will improve if the patient responds to antiresorptive therapy.
Ideal imaging test:
(1) no or little radiation
(2) accurate and precise
(3) inexpensive
(4) convenient if being used for screening
(5) responsive to therapy if used to monitor therapy
DEXA scan of the proximal femur is probably the best all around test and it is the best site for predicting the patient's risk of an osteoporotic fracture.
Specialty: Surgery, orthopedic, Endocrinology, Nutrition
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