Table 1.
Clinical and experimental evaluation of bone strength: some common approaches
| Technique | Outcome | Used in clinical practice? | Advantages | Limitations |
|---|---|---|---|---|
| Imaging | ||||
| DXA | Areal (2D) BMD | Yes, widely accessible | Validated in peri- and postmenopausal population; used in conjunction with medical history and clinical findings to estimate absolute 10-year fracture risk | Low precision, hence provides no insight into bone microarchitecture; trabecular and cortical BMD viewed collectively |
| QCT | Low-resolution (~500 μm) volumetric (3D) BMD (vBMD), which can be further analyzed by mathematical modeling | No; typically used in a research setting | Resolves trabecular and cortical compartment BMD in hip and spine | No insight into microarchitecture; not validated as a prognostic tool in osteoporosis |
| pQCT | Low-resolution (300–500 μm) vBMD, which can be further analyzed by mathematical modeling | No; typically used in a research setting | Resolves trabecular and cortical compartment BMD in tibia and radius | Not validated as a prognostic tool in osteoporosis; not used for imaging vertebral bone |
| HR-pQCT | High-resolution (~60–82 μm) vBMD, which can be further analyzed by mathematical modeling | No; research tool only | Detailed microarchitecture of peripheral bones, particularly radius and tibia. Low radiation dose per exposure (0.003 mSv vs 0.13 mSv for standard HR-pQCT use)43,79 | Not validated as a prognostic tool in osteoporosis; not used for imaging vertebral or hip bone |
| Mathematical modeling | ||||
| FEA | Estimate of whole bone strength | No; typically used in a research setting | Allows modeling of outcomes following falls or other specific types of mechanical load | Not validated as a prognostic tool |
| Polar moment of inertia | Bone’s ability to resist torsion | No | ||
| Biochemistry | ||||
| Bone turnover markers | Analysis of blood or urine to identify products of osteoclast (resorption) or osteoblast (formation) activity | Yes | Inexpensive, safe, and noninvasive; rapid response following treatment; changes may be maintained during treatment | Not standardized Not validated as prognostic tools |
Abbreviations: BMD, bone mineral density; vBMD, volumetric bone mineral density; DXA, dual-energy X-ray absorptiometry; FEA, finite element analysis; mSv, milliSievert; pQCT, peripheral quantitative computed tomography; QCT, quantitative computed tomography; HR-pQCT, High Resolution-peripheral quantitative computed tomography.