Automated Bone Central Axis Extraction from 3D MicroCT Images

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Solution Overview

Problem

Conventional image analysis systems for microCT images of bones require significant manual input and are limited by the use of principal axes, which do not capture detailed shape and directional information, making automated stereological analysis and slice-by-slice characterization of bones inefficient and inaccurate.

Innovation Solution

The automated detection and localization of central axes of skeletal bones using morphological processing, skeletonization, and pruning techniques to identify the medial path and shape of bones, enabling precise 2-D slice-by-slice analysis without user interaction.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If conventional image analysis systems use principal axes for bone analysis, then the analysis process is simplified, but detailed shape and directional information is lost

Engineering Contradiction:
Improvesimplicity of analysis processVSAvoidshape and directional information
Core Design Contradiction:
Ease of operationVSLoss of information

Solution Approach 1:

The patent segments the bone structure into a skeleton representation that preserves local geometric features. Instead of using a single principal axis, the bone is divided into multiple skeletal elements that capture local shape and directional information along the bone's length, resolving the contradiction between simplification and information retention

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent transitions from 2D principal axis representation to 3D central axis representation that incorporates curvature and spatial orientation. By elevating the representation to three dimensions with explicit curvature modeling, the system maintains simplicity while preserving detailed shape and directional information that would be lost in 2D projection

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Measurement precision

If manual input is required for bone analysis, then analysis accuracy can be maintained, but analysis speed and productivity decrease

Engineering Contradiction:
Improveanalysis accuracyVSAvoidanalysis speed
Core Design Contradiction:
Measurement precisionVSProductivity

Solution Approach 1:

The system performs automated skeletonization and central axis extraction without requiring manual user input. The algorithm independently identifies bone structures, generates skeletal representations, and extracts measurement data, achieving both high accuracy and productivity through self-service automation

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The patent replaces manual mechanical measurement processes with automated image processing algorithms. The skeletonization algorithm and central axis extraction methods substitute human operators with computational systems that maintain measurement precision while dramatically increasing analysis speed

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Power

If principal axes are used for bone characterization, then the method is computationally efficient, but curved or non-straight bones cannot be accurately characterized

Engineering Contradiction:
Improvecomputational efficiencyVSAvoidcharacterization accuracy of curved bones
Core Design Contradiction:
PowerVSMeasurement precision

Solution Approach 1:

The patent introduces dynamic curvature modeling that adapts to the bone's geometry. The central axis representation incorporates variable curvature along the bone's length, allowing the system to maintain computational efficiency while accurately characterizing both straight and curved bones through adaptive geometric modeling

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system changes the representation parameters from fixed principal axes to flexible central axes with curvature parameters. By introducing curvature as a variable parameter that can change along the bone's length, the method maintains computational efficiency while achieving accurate characterization of curved bone structures

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP3432797B1Systems and methods for characterizing a central axis of a bone from a 3D anatomical image
Publication Date: 2021.06.16 REVVITY HEALTH SCIENCES INC
  • EP3432797B1 patent drawingFigure 1~2
  • EP3432797B1 patent drawingFigure 3
  • EP3432797B1 patent drawingFigure 4~5

AI summary

Presented herein are efficient and reliable systems and methods for calculating and extracting three-dimensional central axes of bones of animal subjects - for example, animal subjects scanned by in vivo or ex vivo microCT platforms - to capture both the general and localized tangential directions of the bone, along with its shape, form, curvature, and orientation. With bone detection and segmentation algorithms, the skeletal bones of animal subjects scanned by CT or microCT scanners can be detected, segmented, and visualized. Three dimensional central axes determined using these methods provide important information about the skeletal bones.