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Bone Analysis

The separately licensed Bone Analysis module for Dragonfly is a pre-clinical research application designed for the evaluation of high-resolution micro-CT image data of bone specimens. Bone Analysis provides 3D vector-based mappings of surface and volume anisotropy magnitude and directionality and 3D scalar-based mappings of volume fraction (see Mappings). In addition, an automated separation of cortical and trabecular bone in whole bone specimens drives the calculation of common bone morphometric indices that provide researchers with additional quantitative descriptions of bone micro-architecture (see Morphometric Indices).

Bone Analysis dialog and Dragonfly workspace

The Bone Analysis module for Dragonfly requires a high-performance workstation equipped with 32+ GB of RAM to handle processing and visualization demands. You can review the system requirements and recommendations on the ORS website (www.theobjects.com/dragonfly/system-requirements.html).
Currently available micro-CT scanners can achieve an isotropic voxel size as low as a few micrometers, which should be sufficient for investigating structures such as mouse trabeculae that have widths of approximately 30 to 50 micrometers. You should also note that measurement error will decrease as the ratio of voxel size to object size decreases, regardless of scale.
ClosedMappings

3D vector-based mappings of anisotropy magnitude and orientation, as well as 3D scalar based mappings of volume fraction, can be computed for partial and whole bone specimens and then visualized and evaluated in 3D views. Measurements can be thresholded and different color maps can be applied to optimize visualizations (see Computing and Visualizing Mappings of Anisotropy and Volume Fraction).

Mappings of anisotropy and volume fraction

Mappings of anisotropy and volume fraction

In the panel above, the image on the left shows anisotropy mapped by magnitude, with red being very anisotropic and blue isotropic. The image in the middle show the same map replotted in such a way that the color corresponds to orientation, while the image on the right shows the volume fraction of the segmented bone tissue.

Several studies show that the degree of anisotropy, a description of how the structural elements are oriented, together with bone volume fraction may explain a significant part of the mechanical properties of 3D structures.
ClosedMorphometric Indices

Dragonfly's Bone Analysis module can separately identify and segment cortical and trabecular bone in whole-bone specimens and then compute common bone morphometric measurements, as described by Bouxsein et al*. Both global measurements and slice-by-slice measurements are available to evaluate bone micro-architecture (see Computing Cortical and Trabecular Measurements).

Global measurements of cortical and trabecular indices (see Computing Global Measurements) are available directly in the Bone Analysis dialog, shown below. Computed results can be exported in comma-separated values files (*.csv extension).

Bone Analysis dialog

Bone Analysis dialog

In addition to the global measurements available for bone morphometric indices, per slice measurements in any oblique for segmented areas are available in the Slice Analysis dialog (see Computing Slice-by-Slice Measurements). The input for computing slice-by-slice measurements can be any region of interest — segmented bone, cortical bone, or trabeculae. Computed results can be exported in comma-separated values files (*.csv extension).

Slice Analysis dialog

Slice Analysis dialog

* Bouxsein et al, Guidelines for assessment of bone microstructure in rodents using micro-computed tomography, Journal of Bone and Mineral Research, 25, 7, (1468-1486), (2010).

ClosedWhat's Next

Bone Analysis Workflow

Data Preprocessing

Computing Cortical and Trabecular Measurements

Computing and Visualizing Mappings of Anisotropy and Volume Fraction

To help familiarize yourself with the features of this module, you can follow the available Bone Analysis Tutorials.

 

Dragonfly Help Live Version

ClosedPRODUCT INFORMATION

Dragonfly 2021.3 / Dragonfly Pro 2021.3
ClosedCOMPANY INFORMATION

Object Research Systems (ORS) Inc.

760 Saint-Paul West

Montreal (QC) H3C 1M4

www.theobjects.com

Phone +1.514.843.3861

Fax +1.514.543.5475