Magnetic Resonance Susceptibility Artifact Compensation
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Solution Overview
Problem
Magnetic resonance scans often suffer from signal voids due to susceptibility jumps at tissue boundaries, leading to susceptibility artifacts, which are challenging to fully eliminate with existing methods that rely on empirical calculations and time-consuming corrections.
Innovation Solution
An automated method for calculating and applying a compensation moment to mitigate susceptibility artifacts by differentiating between tissue sections with varying susceptibility values, using adjustment image datasets and B0 or B1 maps to determine the necessary compensation, and applying it during the scan sequence to minimize signal loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If z-shim correction is used to reduce susceptibility artifacts, then susceptibility artifacts are reduced, but the calculation is empirical and time-consuming
Solution Approach 1:
The patent applies preliminary action by calculating the compensation moment before the actual imaging sequence using adjustment image datasets and B0/B1 maps. The compensation moment is determined in advance based on susceptibility jump detection, allowing the actual imaging to proceed without time-consuming empirical calculations during the scan.
Solution Approach 2:
The patent replaces the empirical, iterative z-shim correction method with a deterministic calculation approach using B0 or B1 maps and susceptibility jump detection. This substitution eliminates the need for time-consuming trial-and-error adjustments by directly computing the compensation parameters from measured field inhomogeneities.
2Object-affected harmful factors
If echo time TE is reduced to minimize in-plane dephasing, then susceptibility artifacts are reduced, but the signal-to-noise ratio may be affected
Solution Approach 1:
The patent applies preliminary anti-action by introducing a compensation moment that counteracts the susceptibility-induced field inhomogeneities before they can cause dephasing. This preemptive correction allows the use of longer echo times without suffering from susceptibility artifacts, thereby maintaining signal-to-noise ratio while reducing artifacts.
3Object-affected harmful factors
If spin-echo-based recording methods with refocusing pulses are used, then susceptibility artifacts are eliminated, but the recording time and sequence complexity increase
Solution Approach 1:
The patent introduces an intermediary compensation moment as a mediator between the excitation pulse and signal readout. This compensation gradient moment acts as an intermediate corrective element that counteracts susceptibility effects without requiring complex spin-echo refocusing sequences, thereby simplifying the overall pulse sequence while achieving artifact reduction.
4Measurement precision
If automated calculation of compensation moment is implemented, then accuracy and reliability are improved, but the computational requirements increase
Solution Approach 1:
The patent applies partial action by calculating the compensation moment only for the specific region of interest where susceptibility jumps are detected, rather than performing full-field empirical corrections. The calculation uses targeted B0 or B1 maps and susceptibility jump locations to determine compensation parameters, reducing computational load while maintaining accuracy in critical areas.
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
The automated calculation and application of compensation moments significantly reduce susceptibility artifacts, improving image quality by minimizing signal loss and allowing for real-time adaptation to changes in susceptibility jumps during the scan.
Implementation Method 1
a) automated calculation of at least one compensation moment as a function of at least one jump in susceptibility present in the region of interest between two sections of a region of interest, c) application of the at least one compensation moment for the at least partial compensation of a gradient moment caused by the jump in susceptibility
Implementation Method 2
b) application of an excitation pulse, d) reading-out the signal generated by the excitation pulse
Data Source
AI summary
In a method and apparatus for recording a magnetic resonance dataset of a volume of interest of an object, at least one gradient moment is calculated as a function of at least one jump in susceptibility that is present in the volume of interest, between two sections of the volume of interest. An excitation pulse is radiated and at least one compensation moment is activated in a part volume of the volume of interest, for the at least partial compensation of a gradient moment caused by the jump in susceptibility. The signal generated by the excitation pulse is read out.