MRI Auto-Detection Adaptive Encoding Metal Artifacts

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Solution Overview

Problem

Conventional MRI techniques face challenges in imaging objects with metal implants due to susceptibility effects, leading to artifacts and prolonged imaging times, as the number of encoding steps required varies with the type and size of metal, making it difficult to determine the optimal number of encodings needed for effective image correction.

Innovation Solution

The method analyzes MRI k-space data to determine the relevant offset frequency spectrum and adjusts the number of additional frequency encodings dynamically, using auto-detection and adaptive encoding techniques to optimize image quality while reducing imaging time.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If conventional approaches use additional encoding steps to cover offset frequency spectrum, then image quality is improved, but imaging time increases

Engineering Contradiction:
Improveimage qualityVSAvoidimaging time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The patent applies dynamics by making the number of encoding steps adaptive rather than fixed. The system dynamically adjusts the number of additional encodings based on real-time analysis of the offset frequency spectrum, selecting only the necessary number of encodings to achieve adequate artifact suppression, thereby reducing imaging time while maintaining image quality.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes the parameter of encoding steps from a static predetermined value to a dynamic value determined by analyzing the offset frequency spectrum. By detecting the actual offset frequency characteristics and adjusting the number of encodings accordingly, the system optimizes the balance between image quality and imaging time.

Inventive Principle:
Principle #35Parameter changes

2Device complexity

If heuristics are employed to determine number of encodings, then device complexity is reduced, but imaging time may be unnecessarily long or image quality compromised

Engineering Contradiction:
Improvecontrol complexityVSAvoidimaging time
Core Design Contradiction:
Device complexityVSLoss of time

Solution Approach 1:

The patent implements feedback by analyzing the offset frequency spectrum from scout data and using this information to determine the appropriate number of additional encodings. This feedback mechanism allows the system to automatically adjust the encoding steps based on actual imaging conditions, avoiding both over-encoding (wasting time) and under-encoding (compromising quality) that occurs with heuristic approaches.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The system performs self-service by automatically detecting and analyzing the offset frequency spectrum to determine the required number of encodings without requiring manual intervention or complex external control. The MRI system uses its own acquired data to make intelligent decisions about encoding parameters, simplifying control while optimizing imaging efficiency.

Inventive Principle:
Principle #25Self-service

3Device complexity

If fixed number of encodings is used, then device complexity is reduced, but adaptability to different metal types is compromised

Engineering Contradiction:
Improvecontrol complexityVSAvoidadaptability to metal types
Core Design Contradiction:
Device complexityVSAdaptability or versatility

Solution Approach 1:

The patent transforms the fixed number of encodings into a dynamic parameter that adapts to different metal types. By analyzing the offset frequency spectrum specific to each metal implant and adjusting the number of additional encodings accordingly, the system achieves adaptability to various metal characteristics without requiring complex manual configuration.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes the encoding parameter from a fixed value to a variable value that depends on the detected metal type and its offset frequency spectrum. This parameter change enables the system to adapt to different metal implant characteristics (stainless steel, titanium, etc.) while maintaining relatively simple control through automated detection and adjustment.

Inventive Principle:
Principle #35Parameter changes

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 allows for improved suppression of metal-induced susceptibility artifacts in a shorter time, providing better image quality and reducing unnecessary encoding steps, thus enhancing diagnostic information without prolonging imaging sessions.

Implementation Method 1

magnetic resonance imaging (MRI)

Methodology Applied
Scientific EffectMagnetic resonance:

Implementation Method 2

the Larmor frequency and other parameters

Methodology Applied
Scientific EffectLarmor frequency:

Implementation Method 3

the metal may introduce a susceptibility effect that in turn produces a B0 field inhomogeneity

Methodology Applied
Scientific EffectSusceptibility effect:

Implementation Method 4

frequency encoding and a slice selection gradient

Methodology Applied
Scientific EffectMagnetic gradient:

Data Source

PatentUS9971009B2Magnetic resonance imaging (MRI) with auto-detection and adaptive encodings for offset frequency scanning
Publication Date: 2018.05.15 CASE WESTERN RESERVE UNIV
  • US9971009B2 patent drawing
  • US9971009B2 patent drawing
  • US9971009B2 patent drawing

AI summary

Example apparatus and methods provide improved resolution over conventional magnetic resonance imaging (MRI) that is affected by the presence of metal (e.g., prosthetic hip) in the MRI field of view (FOV). Embodiments may excite a slice that is affected by a susceptibility effect produced by metal. Embodiments may excite the slice using a first pre-determined frequency and a plurality of scout frequency encodings. Embodiments may acquire nuclear magnetic resonance (NMR) signal data from the slice in response to the first pre-determined frequency and the plurality of scout frequency encodings and select frequency encodings to use to image the slice as a function of an amplitude of the NMR signal data. Frequency encodings are selected to produce data that will help account for distortions caused by the susceptibility effect.