3D Skeletal Density Model from DXA Projections
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Solution Overview
Problem
Current 2-D Dual-energy X-ray Absorptiometry (DXA) systems fail to provide accurate 3-D volumetric density information for skeletal assessment, while Quantitative Computed Tomography (QCT) offers high-quality but costly and radiatively intensive results.
Innovation Solution
A method and system that generate a customized 3-D model using DXA images, applying density gains from synthesized projection images to create a density-enhanced model, providing spatial geometry and volumetric density information comparable to QCT with reduced patient exposure and costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If QCT is used to obtain volumetric density information, then measurement precision is improved, but patient radiation exposure increases
Solution Approach 1:
The patent creates a virtual 3D copy of the patient's skeletal structure using DXA images as input. This virtual model replicates the anatomical geometry and applies density information derived from the 2D images, providing QCT-quality volumetric density assessment without requiring actual QCT scanning and its associated radiation exposure
Solution Approach 2:
The patent introduces a customized 3D model as an intermediary between the low-radiation DXA imaging and the high-quality volumetric density assessment. This model acts as a mediator that translates 2D projection data into 3D density information, eliminating the need for direct QCT scanning
2Measurement precision
If QCT is used to obtain volumetric density information, then measurement precision is improved, but examination cost increases
Solution Approach 1:
The system creates a virtual replica of the skeletal structure from inexpensive DXA images, avoiding the need for expensive QCT scanning equipment and procedures. This copying approach provides comparable measurement precision at a fraction of the cost
Solution Approach 2:
The patent makes the DXA system multi-functional by enabling it to perform both its traditional 2D bone density assessment and 3D volumetric density assessment through software processing. This eliminates the need for separate QCT equipment and reduces overall examination costs
3Measurement precision
If QCT is used to obtain volumetric density information, then measurement precision is improved, but examination time increases
Solution Approach 1:
The patent performs preliminary 3D model construction and density mapping using DXA images before any QCT scanning would be required. By pre-processing the available 2D data into a customized 3D model with density information, the system eliminates the time-consuming QCT scanning step entirely
4Object-affected harmful factors
If DXA is used for skeletal assessment, then patient radiation exposure is minimized, but volumetric density information is lost
Solution Approach 1:
The patent transforms 2D DXA projection images into a 3D virtual model by adding the dimension of depth and volume through mathematical reconstruction. This dimensionality conversion recovers the volumetric density information that would otherwise be lost, while maintaining the low-radiation advantage of DXA
Solution Approach 2:
The patent replaces the physical QCT scanning mechanism with a computational approach. Instead of using mechanical/physical X-ray tomography to obtain 3D data, the system uses image processing algorithms to synthesize 3D volumetric information from 2D projections, substituting computational methods for physical measurement
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The density-enhanced model achieves accurate skeletal assessment results similar to QCT, minimizing radiation exposure, equipment costs, and examination time.
Implementation Method 1
By comparing the relative attenuation of the x-rays at the two energies, the contributions to the attenuation due to the soft tissue can be subtracted
Data Source
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AI summary
A method of generating a density enhanced model of an object is described. The method includes generating a customized a model of ars object using a pre-defined set of models in combination with at least one projection image of the object, where the customized mode! is formed of a pEura?ty of volume elements including density information. A density map is generated by relating a synthesized projection image of the customized modei to an actual projection image of the object. Gains from the density map are back-projected into the customized model to provide a density enhanced customized model of the object. Because the density map is calculated using information from the synthesized projection image in combination with actual projection images of the structure, it has been shown to provide spatial geometry and volumetric density results comparable to those of QCT but with reduced patient exposure, equipment cost and examination time.