BMA: Bone Microarchitecture Analysis Add-On

Bone Microarchitecture Analysis for MicroCT Data

The Bone Micro Analysis (BMA) module is available as an add-on for Analyze. BMA is a powerful pre-clinical research application designed for the evaluation of microCT data. The module provides the ability to process long bone specimens and isolate 3D samples of cortical bone, trabecular bone and trabecular tissue. It generates an extensive set of bone measurements as described by Bouxsein et al.

BMA provides automatic and user-guided isolation of bone from non-bone tissue and identification of both cortical and trabecular bone. The module uses the segmented regions to automatically drive the calculation of common bone measurements that provide a quantitative description of bone microarchitecture. The specific measurements for trabecular and cortical bone made by the BMA module are listed below.

Watch the BMA Step-by-Step Video

Download the BMA Users Manual

Bone Microarchitecture Analysis Workflow

Preprocessing

The BMA add-on module requires that long bone specimens are isovolumetric. If the image data contains multiple bones the bone of interest must be isolated and orientated into the correct anatomical orientation. All tools needed for data preprocessing are provided with Analyze.

Cortical Bone Segmentation

Once the image data is loaded the BMA add-on will conduct a preliminary segmentation which will allow the module to identify the cortical shell, cortical pores and trabecular tissue regions.

Trabecular Bone Segmentation

Upon user approval the add-on will now complete the segmentation process by identifying the trabecular bone in the trabecular region. Two new regions, the trabecular bone and intra-trabecular space will be derived.

Calculate Bone Measurements

Measurements are automatically calculated for the trabecular and cortical bone and output in several comma-separated value (.csv) files. A utility is also provided to convert CT numbers (HUs) to Bone Mineral Density (BMD) in units of mg/CC.

Table 1. Trabecular Bone Measurements

Abbreviation	Description	Unit
TV	Total Volume	mm³
BV	Bone Volume	mm³
BS	Bone Surface	mm²
BV/TV	Bone Volume Fraction	%
BS/TV	Bone Surface Density	mm²/mm³
BS/BV	Specific Bone Surface	mm²/mm³
Conn.D	Connectivity Density	1/mm³
SMI	Structure Model Index
Tb.N	Trabecular Number	1/mm
Tb.Th	Trabecular Thickness	mm
Tb.Sp	Trabecular Separation	mm
Tb.Th.SD	Standard Deviation of Trabecular Thickness	mm
Tb.Sp/SD	Standard Deviation of Trabecular Seperation	mm
DA	Degree of Anisotropy
MIL	Mean Intercept Length

Table 2. Cortical Bone Measurements

Abbreviation	Description	Unit
Tt.Ar	Total Cross-Sectional Area	mm²
Ct.Ar	Cortical Bone Area	mm²
Ma.Ar	Medullary Area	mm²
Ct.Ar/Tt.Ar	Cortical Area Fraction	%
Ct.Th	Average Cortical Thickness	mm
Ps.Pm	Periosteal perimeter	mm
Ec.Pm	Endocortical Perimeter	mm
I_ap	Moment of Inertia Anteroposterior Axis	mm⁴
I_ml	Moment of Inertia Mediolateral Axis	mm⁴
I_max	Maximum Moment of Inertia	mm⁴
I_min	Minimum Moment of Inertia	mm⁴
J	Polar Moment of Inertia	mm⁴
Ct.Po	Cortical Porosity	%
Po.N	Pore Number	n
Po.V	Total Pore Volume	mm³
AvgPo.V	Average Pore Volume	mm³
Po.V.SD	Standard Deviation of Pore Volume	mm³
Po.Dn	Pore Density	1/mm³

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