Bland Altman plots for reproducibility of CBCT(A)-data.

<p>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.</p

Results of simple linear regression with stiffness as dependent variable.

<p>Results of simple linear regression with stiffness as dependent variable.</p

Predicting Trabecular Bone Stiffness from Clinical Cone-Beam CT and HR-pQCT Data; an In Vitro Study Using Finite Element Analysis

<div><p>Stiffness and shear moduli of human trabecular bone may be analyzed in vivo by finite element (FE) analysis from image data obtained by clinical imaging equipment such as high resolution peripheral quantitative computed tomography (HR-pQCT). In clinical practice today, this is done in the peripheral skeleton like the wrist and heel. In this cadaveric bone study, fourteen bone specimens from the wrist were imaged by two dental cone beam computed tomography (CBCT) devices and one HR-pQCT device as well as by dual energy X-ray absorptiometry (DXA). Histomorphometric measurements from micro-CT data were used as gold standard. The image processing was done with an in-house developed code based on the automated region growing (ARG) algorithm. Evaluation of how well stiffness (Young’s modulus E3) and minimum shear modulus from the 12, 13, or 23 could be predicted from the CBCT and HR-pQCT imaging data was studied and compared to FE analysis from the micro-CT imaging data. Strong correlations were found between the clinical machines and micro-CT regarding trabecular bone structure parameters, such as bone volume over total volume, trabecular thickness, trabecular number and trabecular nodes (varying from 0.79 to 0.96). The two CBCT devices as well as the HR-pQCT showed the ability to predict stiffness and shear, with adjusted R²-values between 0.78 and 0.92, based on data derived through our in-house developed code based on the ARG algorithm. These findings indicate that clinically used CBCT may be a feasible method for clinical studies of bone structure and mechanical properties in future osteoporosis research.</p></div

Results [R²] of stepwise multiple linear regression with stiffness [E3] and shear [minimum in 12,13 or 23 plane] respectively as dependent variable.

<p>Results [R²] of stepwise multiple linear regression with stiffness [E3] and shear [minimum in 12,13 or 23 plane] respectively as dependent variable.</p

Results of linear regressions with shear as dependent variable.

<p>Results of linear regressions with shear as dependent variable.</p

Image of the FE-model of one bone specimen.

<p>The FE-model, of the same wrist cube as in Figs <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0161101#pone.0161101.g001" target="_blank">1</a> and <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0161101#pone.0161101.g002" target="_blank">2</a>, used to calculate Young’s modulus (E1, E2, E3) and minimum shear modulus (G^min). The model is based on the segmented micro-CT data.</p

Correlations with micro-CT.

<p>Correlations with micro-CT.</p

Images of one bone specimen imaged by the different scanners.

<p>(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.</p

Different plaque types, as seen by cardiac computed tomography.

<p>A non-calcified plaque is shown in longitudinal and cross section (A and B). The degree of stenosis was 20–50%. A large mixed plaque is shown in longitudinal section (C) and in cross section at the level of non calcified (D) and calcified (E) components. A large calcified plaque is shown to the right. (F and G). The mixed and calcified plaques (C to G) were both eccentric in location and the degree of stenosis was <20%.</p

Baseline characteristics.

<p>Abbreviations: MINCA, myocardial infarction with angiographically normal coronary arteries; CAD, coronary artery disease; BMI, body mass index; SD, standard deviation. Data are presented as mean ± SD or absolute value (percentage).</p><p>*P<0.05,</p>†<p>P<0.01, using Fisher’s exact test.</p