MRI K-Space RF Chopping to Reduce Fine-Line Artifacts
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Solution Overview
Problem
Existing MRI techniques struggle with fine-line artifacts, which are unwanted visual distortions caused by system imperfections, and current methods to reduce these artifacts either increase echo spacing time or double the scan time.
Innovation Solution
A method and system that applies RF chopping in every other blade during k-space data acquisition, alternating the polarity of excitation pulses to induce destructive interference and reduce fine-line artifacts without increasing echo spacing or scan time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If gradient crusher areas are increased to reduce fine-line artifacts, then fine-line artifacts are reduced, but echo spacing time increases causing blurring in the image
Solution Approach 1:
The patent changes the polarity parameter of excitation pulses alternately for different blades in k-space sampling. By inverting the polarity of every other blade, the unwanted signals that cause fine-line artifacts are made to interfere destructively during image reconstruction, reducing artifacts without increasing gradient crusher areas or echo spacing time
Solution Approach 2:
The patent introduces asymmetry in the k-space sampling process by treating odd and even blades differently through polarity inversion. This asymmetric approach allows selective cancellation of unwanted signals while preserving the desired signal, resolving the contradiction between artifact reduction and image quality
2Object-affected harmful factors
If NEX2 technique is used to reduce fine-line artifacts, then fine-line artifacts are reduced, but scan time doubles
Solution Approach 1:
The patent uses polarity inversion of excitation pulses as a parameter change that achieves artifact reduction within a single scan. By alternating the polarity for different blades and inverting every other blade during reconstruction, the method eliminates fine-line artifacts without requiring multiple excitations, thus avoiding the doubling of scan time associated with NEX2 technique
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
Effectively reduces fine-line artifacts by spreading unwanted signals coherently across the image, improving image quality without extending scan time or causing blurring.
Implementation Method 1
applies RF chopping in every other blade during k-space data acquisition, alternating the polarity of excitation pulses to induce destructive interference and reduce fine-line artifacts
Data Source
AI summary
A method for imaging a subject using an magnetic resonance imaging (MR) system is presented. The method includes sampling a k-space in a rotating fashion using a plurality of radially directed blades around a center of the k-space. A first subset of blades is acquired with a positive excitation pulse and a first plurality of refocusing pulses. Further, a second subset of blades is acquired with a negative excitation pulse and a second plurality of refocusing pulses. The polarity of the second subset of blades is inverted to generate a third subset of blades. The first subset of blades and the third subset of blades are then combined to generate a final k-space. Finally, a medical image of the subject is generated based on a reconstruction of the final k-space.