Multi-Energy Metal Artifact Reduction in CT Imaging

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Solution Overview

Problem

Current methods for metal artifact reduction in computed tomography (CT) image data, such as normalized sinogram interpolation, are prone to errors when metal artifacts are mistaken for metal objects or when other highly attenuating materials are present, leading to suboptimal results.

Innovation Solution

A method that segments metal areas in the projection or image domain, corrects projection images by replacing data in metal areas with interpolated data, and reconstructs an artifact-reduced 3D image dataset, utilizing multi-energy information to improve segmentation and material classification, thereby enhancing image quality.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If normalized sinogram interpolation is used to replace corrupted projection data, then metal artifacts are reduced, but errors occur when metal artifacts are mistaken for metal objects or when other highly attenuating materials are present

Engineering Contradiction:
Improvemetal artifactsVSAvoidsegmentation accuracy
Core Design Contradiction:
Object-affected harmful factorsVSReliability

Solution Approach 1:

The patent segments metal areas in the projection or image domain to identify regions affected by metal artifacts. By dividing the image into distinct material regions (metal, bone, soft tissue), the method enables selective correction only in metal-affected areas, avoiding misclassification of other high-attenuation materials like bone or contrast agents.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent utilizes multi-energy information to change the parameter space for material differentiation. By acquiring and analyzing projection data at multiple energy levels, the system can distinguish between metal and other high-attenuation materials based on their different energy-dependent attenuation characteristics, thereby improving segmentation reliability.

Inventive Principle:
Principle #35Parameter changes

2Measurement precision

If multi-energy information is used to improve material classification, then segmentation accuracy is improved, but device complexity increases

Engineering Contradiction:
Improvematerial classification accuracyVSAvoidsystem complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent employs a photon-counting detector that can operate in multiple energy bins simultaneously, making the detection device multi-functional. This single detector performs both standard CT imaging and spectral differentiation tasks, avoiding the need for separate imaging systems while achieving improved material classification.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent replaces complex mechanical material differentiation methods with computational analysis of multi-energy projection data. Instead of using physical separation or multiple imaging systems, the solution uses algorithmic processing of spectral information to distinguish materials, reducing mechanical complexity while maintaining high classification accuracy.

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

Data Source

PatentUS11419568B2Multi-energy metal artifact reduction
Publication Date: 2022.08.23 SIEMENS HEALTHINEERS AG
  • US11419568B2 patent drawing
  • US11419568B2 patent drawing
  • US11419568B2 patent drawing

AI summary

A method is for metal artifact reduction in CT image data, the CT image data including multiple 2D projection images acquired using different projection geometries and suitable to reconstruct a 3D image data set of a volume of an imaged object. In an embodiment, the method includes a metal artifact reduction process including at least, acquiring, using a multi-energy CT technique, energy-resolved CT image data associated with multiple energy ranges. At least one result of the multi-energy technique is used in at least one aspect of the metal artifact reduction process.