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Fig. 11 MDCT-based FEM
of a vertebra (T10) in-vitro.
The BMD distribution is
color-coded and used for the
assignment of the material
properties for each element of
the FEM
strength (AUC = 0.83), volumetric BMD (AUC = 0.82), and the load-to-strength
ratio (AUC = 0.82). Thus, FEM-based vertebral compressive strength and volu-
metric BMD consistently improved vertebral fracture risk assessment compared to
areal BMD as assessed by DXA.
Furthermore, trabecular bone microstructure parameters and FEM revealed drug
effects which were partly not captured by BMD measurements. Graeff et al. [
87
]
performed high-resolution MDCT imaging of T12 in 65 postmenopausal women
with established osteoporosis after 0, 6, and 12 months of teriparatide treatment.
Interestingly, changes in trabecular bone microstructure parameters exceeded and
were partially independent of changes in BMD. Thus, longitudinal analysis of
trabecular bone microstructure at the spine offers information beyond BMD. Similar
findings were reported with regard to the effects of teriparatide, alendronate, and
risedronate on vertebral bone strength as assessed by MDCT-based FEMs [
88
90
].
-
findings underline the importance of high-resolution bone imaging for
fracture risk assessment and therapy monitoring. However, in-vivo MDCT imaging
for trabecular bone microstructure analysis and FEMs is associated with an effective
dose of estimated 3 mSv according to Graeff et al. [
87
]. This dose is in the upper range
of the medically indicated radiation exposure. Therefore, these measurements are
currently limited to research trials and cannot be used in clinical routine. In the future,
it remains critical for MDCT imaging of bone microstructure at the spine to con-
siderably reduce the radiation exposure. Newly developed CT reconstruction algo-
rithms (e.g. iterative reconstruction) and
These
flat-panel CT devices may have the potential
to reliably assess trabecular bone microstructure with less radiation dose [
91
].
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