Table 1.
Imaging parameters.
Fig 1.
Images of one bone specimen imaged by the different scanners.
(A) The same wrist cube imaged by the four different CT machines. Volume renderings of the 3D bone cube are shown in the upper row. Volume renderings of the excised 3D trabecular bone cubes are shown in the second row. Raw images slices are shown in the third row. Segmented images slices are shown in the lower row, where the HR-pQCT data from Xtreme CT is segmented using both an implementation of ARG (automated 3D region algorithm) and an implementation of SCANCO Medical.
Fig 2.
Image of one bone specimen imaged by DXA.
The same wrist cube imaged using DXA. The arrow indicates the cortical bone and the white box indicates the volume visualized in Fig 1A, from which the DXA-BMD was calculated.
Fig 3.
Image of the FE-model of one bone specimen.
The FE-model, of the same wrist cube as in Figs 1 and 2, used to calculate Young’s modulus (E1, E2, E3) and minimum shear modulus (Gmin). The model is based on the segmented micro-CT data.
Table 2.
Correlations with micro-CT.
Table 3.
Results of simple linear regression with stiffness as dependent variable.
Table 4.
Results of linear regressions with shear as dependent variable.
Fig 4.
Graphs showing stiffness and shear from micro-CT and predicted stiffness and shear from clinical CT-machines.
The stiffness derived by finite element analysis based on micro-CT data as a function of predicted stiffness, calculated as Young’s Modulus E3 (left panels) and Minimum shear (Gmin) (right panels) based on regression analysis from a single bone parameter (upper panels) or two bone parameters (lower panels). For both stiffness and shear with CBCT 3D Accuitomo 80 and HR-pQCT Xtreme CT data, the single parameter was trabecular termini and the second parameter bone volume over total volume. For both stiffness and shear with CBCT NewTom 5G data, the single parameter was bone volume over total volume and the second parameter trabecular spacing. For stiffness with micro-CT μCT 40 data, the first parameter was bone volume over total volume and the second parameter trabecular thickness. For shear with micro-CT μCT 40 data, the single parameter was bone volume over total volume and the second parameters trabecular spacing.
Table 5.
Results [R2] of stepwise multiple linear regression with stiffness [E3] and shear [minimum in 12,13 or 23 plane] respectively as dependent variable.
Table 6.
Basic descriptive statistics.
Fig 5.
Bland Altman plots for reproducibility of CBCT(A)-data.
Bland-Altman analysis of long-term reproducibility of the derived parameters describing trabecular bone histomorphometry. The scans of the bone cubes were made using a CBCT 3D Accuitomo 80 with a time interval of two years.