MR Data Artifact Correction via Anatomical Symmetry
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Solution Overview
Problem
Magnetic Resonance (MR) data often experiences artifacts when imaging subjects with metal objects, such as dental implants, leading to degradation in estimating gamma ray attenuation for PET scans, which affects the accuracy of subject structure correction.
Innovation Solution
A system and method that acquire MR data with a magnet assembly and controller, identifying and populating artifact-affected regions with substitute data from anatomically symmetrical regions, generating corrected images to improve attenuation correction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If MRI is used to obtain a model of subject structure for PET attenuation correction, then the ability to estimate gamma ray attenuation is improved, but artifacts appear when imaging subjects with metal objects
Solution Approach 1:
The patent identifies artifact-affected regions in the MR data and converts the harmful artifact information into beneficial substitute data by copying from anatomically symmetrical regions. This transforms the problematic artifact regions into usable data for attenuation correction, allowing the system to maintain accurate gamma ray attenuation estimation even in the presence of metal implants.
Solution Approach 2:
The patent copies data from anatomically symmetrical regions of the subject that are not affected by artifacts and uses this copied data to replace the artifact-affected regions. This copying approach preserves the anatomical structure information needed for attenuation correction while eliminating the harmful artifact effects from the MR data.
2Area of stationary object
If conventional MRI imaging is performed on subjects with metal implants, then imaging coverage is maintained, but artifact corruption and degradation of MR signal occur
Solution Approach 1:
The patent maintains full imaging coverage including artifact-affected regions but converts the harmful artifact signal into beneficial substitute data by copying from symmetrical regions. This allows the system to preserve complete anatomical coverage while restoring signal integrity in previously corrupted areas through the symmetry-based data replacement.
Solution Approach 2:
The patent introduces an intermediary processing step that identifies artifact-affected regions and replaces them with substitute data from anatomically symmetrical regions. This intermediary process acts as a mediator between the raw MR data with artifacts and the final attenuation correction model, eliminating artifacts while preserving complete imaging coverage.
3Productivity
If MR data with artifacts is used for attenuation correction, then imaging speed is maintained, but accuracy of structural modeling deteriorates
Solution Approach 1:
The patent converts the harmful artifact information in the MR data into beneficial substitute data by copying from anatomically symmetrical regions. This conversion process restores structural modeling accuracy without requiring additional imaging time, as the artifact correction is performed through computational processing of the already-acquired MR data.
Solution Approach 2:
The patent copies data from anatomically symmetrical regions to replace artifact-affected areas, thereby restoring structural modeling accuracy. This copying operation is performed computationally on the existing MR data, maintaining imaging speed while significantly improving the accuracy of the attenuation correction model.
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
Enhances the accuracy of attenuation correction in PET-MRI systems by mitigating artifacts, resulting in more precise imaging and improved structural modeling of subjects with metal implants.
Implementation Method 1
Many MRI systems use magnet assemblies that house superconductive magnets to impose a strong main magnetic field on the nuclei in the patient/object to be imaged within a target volume
Implementation Method 2
The nuclei are excited by a radio frequency ('RF') signal typically transmitted via an RF coil at characteristics NMR (Larmor) frequencies. By spatially disturbing localized magnetic fields surrounding the subject within the imaging bore, the nuclei emit RF responses (also referred to herein as the 'MR signal') as the excited protons relax back to their lower energy normal state
Data Source
AI summary
A system for correcting an artifact within MR data is provided. The system includes a magnet assembly and a controller in electronic communication with the magnet assembly. The controller is operative to: acquire the MR data from a subject via the magnet assembly, the MR data having a first portion and a second portion, the first portion including the artifact; and to populate the first portion of the MR data with substitute data corresponding to the second portion. The first portion corresponds to a first region of the subject, and the second portion corresponds to a second region of the subject that is anatomically symmetrical to the first region.