Tomosynthesis Alignment Angle Determination
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Solution Overview
Problem
Current methods for determining the antetorsion angle of the femur during surgical procedures are inadequate due to reliance on insufficient two-dimensional imaging, lack of standardized techniques, and challenges in maintaining sterility and time constraints, leading to frequent complications and joint wear.
Innovation Solution
A method utilizing a mobile X-ray device to record a large number of partially spatially superimposed projection images during translational movement along the bone axis, reconstructing tomosynthesis image data, and determining the alignment angle between bone parts, allowing for precise quantification of the antetorsion angle in three-dimensional images.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If simple two-dimensional X-ray images are used, then the imaging process is simple and fast, but the measurement precision of the antetorsion angle is insufficient
Solution Approach 1:
The patent transitions from two-dimensional projection images to three-dimensional volumetric imaging by implementing a C-arm rotation mechanism that captures X-ray images from multiple angular positions. This dimensional transformation enables precise measurement of the antetorsion angle by providing spatial information about bone structures that cannot be obtained from single-plane projections.
Solution Approach 2:
The system employs dynamic image acquisition during C-arm rotation, capturing a series of images as the imaging device rotates around the patient's body. This dynamic approach allows reconstruction of three-dimensional bone geometry from multiple two-dimensional projections, resolving the contradiction between measurement precision and system complexity.
2Measurement precision
If volumetric imaging (MPR) is used to accurately determine the antetorsion angle, then the measurement precision is sufficient, but the radiation dose increases and the procedure time extends
Solution Approach 1:
The system uses periodic rotation of the C-arm to acquire images at multiple predetermined angular positions. This structured, periodic imaging approach efficiently captures the necessary three-dimensional information in a single rotational cycle, reducing total procedure time while maintaining measurement precision through the use of reconstruction algorithms that process the periodic image set.
Solution Approach 2:
The patent performs preliminary image acquisition during a single C-arm rotation pass, capturing all necessary projection data before reconstruction. This preliminary capture of multi-angle images during one continuous motion eliminates the need for multiple separate scanning passes, significantly reducing procedure time while preserving the ability to reconstruct accurate three-dimensional bone geometry for precise antetorsion angle measurement.
3Measurement precision
If conventional volume scans (CT or DynaCT) are used, then comprehensive three-dimensional imaging is achieved, but the radiation dose is significantly high
Solution Approach 1:
The system acquires images at a limited number of discrete angular positions during C-arm rotation rather than continuous scanning. This partial sampling approach captures sufficient information for three-dimensional reconstruction of the antetorsion angle while reducing the total radiation dose compared to comprehensive CT volumetric scanning, which images the entire body volume at much higher resolution and density.
Solution Approach 2:
The patent extracts only the essential information needed for antetorsion angle measurement from the three-dimensional space. By focusing the C-arm rotation and image acquisition specifically on the hip region and using selective reconstruction techniques, the system obtains the necessary bone geometry data without the excessive radiation dose required for full-body or comprehensive volumetric CT scanning.
4Measurement precision
If alignment is determined by manual feeling or comparison, then the procedure is fast and simple, but the measurement precision and reliability are insufficient
Solution Approach 1:
The patent replaces manual tactile assessment and visual comparison methods with an automated imaging and measurement system. The C-arm rotation combined with computerized reconstruction algorithms and software-based angle measurement eliminates the subjectivity and imprecision of manual alignment determination, providing objective, quantifiable measurements of the antetorsion angle while maintaining ease of operation through automated processing.
Solution Approach 2:
The system performs self-measurement by automatically calculating the antetorsion angle from the acquired three-dimensional bone images. The reconstruction software identifies key anatomical landmarks and computes alignment angles without requiring manual manipulation or subjective interpretation by the surgeon, thereby improving measurement precision while keeping the operational process simple and efficient.
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
Enables accurate and efficient determination of the antetorsion angle with reduced radiation dose, facilitating precise alignment of bone parts during surgery, thereby reducing complications and improving surgical outcomes.
Implementation Method 1
Recording of a large number of partially spatially superimposed projection images by a recording system of an X-ray device
Data Source
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AI summary
The invention comprises a method for determining the alignment between at least two bone parts of an elongated skeletal system of a patient, comprising the following steps: • Acquisition of a plurality of partially spatially superimposed projection images by a recording system of an X-ray device, in particular a mobile X-ray device, during a translational movement of the X-ray device or the recording system in the direction of or parallel to a longitudinal axis of the skeletal system, • Reconstruction of tomosynthesis image data, in particular of cross-sectional images, of the bone parts from the acquired projection images, and • Determination or estimation of an alignment angle between the at least two bone parts, at least partially, based on the reconstructed tomosynthesis image data and/or the projection images.