3D Printed MRI Phantom for Geometric Distortion Measurement
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Solution Overview
Problem
Current methods for characterizing and correcting geometric distortions in MRI images are hindered by manufacturing imprecision and complexity in fabricating dimensionally accurate 3D grid phantoms for use in image-guided therapy and other applications, particularly due to difficulties in post-processing and analysis of grid intersections.
Innovation Solution
The development of a 3D grid phantom fabricated using additive manufacturing (3D printing) with spherical control points supported by cylindrical struts, allowing for automated segmentation and analysis of 3D distortion fields, and compatible with MRI or CT imaging, enabling precise geometric calibration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If commercially fabricated polystyrene grids are used, then the phantom structure is readily available, but manufacturing precision deteriorates due to manufacturing imprecision
Solution Approach 1:
The patent changes the manufacturing method from commercial fabrication to custom fabrication using techniques like 3D printing, allowing precise control of dimensional parameters. This enables the phantom to be manufactured with high dimensional accuracy while maintaining ease of manufacture through automated fabrication processes.
2Measurement precision
If glass marker beads in custom-fabricated trays are used, then measurement precision can be achieved, but device complexity increases due to complicated fabrication
Solution Approach 1:
The patent merges the control points (beads) and supporting structure (trays) into a single integrated phantom object. This consolidation maintains measurement precision through well-defined control points while reducing fabrication complexity by eliminating the need to separately fabricate and assemble multiple components.
Solution Approach 2:
The patent adopts modern fabrication techniques such as 3D printing that can directly create complex integrated structures with high precision, eliminating the need for traditional multi-step fabrication processes involving custom trays and separate bead placement.
3Measurement precision
If traditional grid phantoms are used, then geometric distortion measurement is possible, but productivity decreases due to difficulty in post-processing and analysis
Solution Approach 1:
The patent designs control points with distinct local properties (specific size, shape, and material characteristics) that differ from the supporting structure. This local differentiation enables automated image processing algorithms to easily identify and segment control points from the background structure, significantly improving post-processing efficiency while maintaining distortion measurement capability.
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
This approach provides a dimensionally accurate and simple-to-manufacture 3D phantom for measuring geometric distortions, facilitating automated analysis and correction of MRI images, enhancing the accuracy and efficiency of image-guided therapies.
Implementation Method 1
When immersed in a fluid, such as a paramagnetic liquid, the phantom can be used to obtain images that facilitate automated segmentation and analysis
Data Source
AI summary
3D printing in MRI-compatible plastic resin has been used to fabricate and implement a geometric distortion phantom for MRI and CT imaging. The sparse grid structure provides a rigid and accurate phantom with identifiable intersections that are larger than the supporting members, which produces images that are amenable to fully automated quantitative analysis using morphometric erosion, greyscale segmentation and centroiding. This approach produces a 3D vector map of geometric distortion that is useful in clinical applications where geometric accuracy is important, either in routine quality assurance or as a component of distortion correction utilities.