Ultrasound Probe Metal Artifact Correction in CT Imaging

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Solution Overview

Problem

Existing metal artifact reduction (MAR) algorithms are ineffective in reducing metal artifacts caused by externally mounted ultrasound probes during X-ray imaging, which can compromise the quality of X-ray images and affect treatment plans in radiation therapy.

Innovation Solution

The method involves reconstructing CT scans from sinogram data and using multi-threshold segmentation to isolate metal data, followed by interpolation and filtered-back projection to correct metal artifacts, making the algorithm applicable to all CT scanner vendors.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional MAR algorithms are used to reduce metal artifacts, then general metal artifacts may be reduced, but ultrasound probe-induced metal artifacts remain ineffective

Engineering Contradiction:

Improveeffectiveness of metal artifact reductionVSAvoidapplicability to ultrasound probe artifacts

Core Design Contradiction:

ReliabilityVSAdaptability or versatility

Solution Approach 1:

The algorithm applies different processing strategies to different regions of the sinogram based on their characteristics. Specifically, it identifies and handles ultrasound probe-induced artifacts differently from other metal artifacts by detecting the specific pattern of missing data in the sinogram domain, thereby achieving localized optimization for probe-induced artifacts while maintaining overall effectiveness

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The invention changes the domain of processing from image space to sinogram space, and modifies the interpolation parameters to account for the specific characteristics of ultrasound probe artifacts. By adjusting the interpolation strategy in the sinogram domain based on the detected artifact pattern, the algorithm achieves effective reduction of probe-induced artifacts that conventional image-space methods cannot handle

Inventive Principle:

Principle #35Parameter changes

2Reliability

If sinogram data in proprietary format is used, then vendor-specific artifact reduction may be achieved, but cross-vendor applicability is limited

Engineering Contradiction:

Improveartifact reduction effectivenessVSAvoidcross-vendor compatibility

Core Design Contradiction:

ReliabilityVSAdaptability or versatility

Solution Approach 1:

The algorithm is designed to work with reconstructed CT images as input rather than requiring access to vendor-specific sinogram data formats. This universal approach allows the same algorithm to be applied across different CT scanner vendors and models, achieving cross-vendor compatibility while maintaining effectiveness in reducing ultrasound probe-induced artifacts

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Productivity

If ultrasound probe is mounted externally for simultaneous imaging, then real-time cardiac motion monitoring is achieved, but metal artifacts compromise X-ray image quality

Engineering Contradiction:

Improvesimultaneous imaging capabilityVSAvoidX-ray image quality

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The algorithm takes the metal artifacts caused by the ultrasound probe and converts them into useful information for correction. By detecting the specific pattern of artifacts in the sinogram domain and using iterative interpolation to reconstruct the missing data, the algorithm transforms the harmful artifacts into an opportunity for improved image quality, enabling simultaneous ultrasound and X-ray imaging without compromising diagnostic accuracy

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

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 effectively reduces metal artifacts caused by ultrasound probes, enhancing X-ray image quality and allowing for simultaneous ultrasound and X-ray imaging, which improves diagnostic accuracy and treatment planning.

Implementation Method 1

Metal artifacts can severely compromise the quality of an X-ray image

Methodology Applied

Scientific EffectX-ray attenuation: Absorption (EM radiation)

Implementation Method 2

followed by interpolation and filtered-back projection to correct metal artifacts

Methodology Applied

Scientific EffectFiltered-back projection:

Data Source

PatentUS12277627B1Correction of ultrasound probe-induced metal artifacts in X-ray based imaging systems

Publication Date: 2025.04.15 QUEENSLAND UNIVERSITY OF TECHNOLOGY

AI summary

A metal artifact reduction (MAR) method and system for reducing metal artifacts from X-ray images. The method is suitable for CT images generated with metallic elements exterior to a patient being scanned, for example, where external probes are applied to a patient, such as ultrasound probes. The method may be embodied in a computer algorithm for use, for example, in radiotherapy treatment planning and patient positioning procedures. In one application, the disclosed technique improves the dose delivery accuracy in ultrasound-guided cardiac radioablation, making this treatment modality a viable option for cardiac arrhythmias.