MRI K-space Data Rearrangement for Artifact Reduction

Solution Overview

Problem

Magnetic resonance imaging (MRI) techniques face challenges in reducing the time required for capturing time-series data of changing subjects, leading to degraded image quality due to undersampling of k-space data, which results in artifacts during reconstruction.

Innovation Solution

The MRI apparatus acquires k-space data with undersampling and rearranges it into a different order for reconstruction, allowing for the generation of MR images with minimized artifacts by transforming the data in x-f space and performing sensitivity encoding, thereby reducing the impact of discontinuities in signal intensity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If k-space data is undersampled to reduce imaging time, then productivity is improved, but measurement precision deteriorates due to artifacts in reconstructed images

Engineering Contradiction:

Improveimaging speedVSAvoidimage quality

Core Design Contradiction:

ProductivityVSMeasurement precision

Solution Approach 1:

The patent applies preliminary action by reordering k-space data along the phase-encoding direction before performing the Fourier transform reconstruction. Specifically, the center portion of k-space data (which contains low-frequency signal components) is positioned to start from a predetermined line (e.g., zeroth or first line) rather than following the conventional sequential order. This preliminary reorganization ensures that signal components with similar frequencies are grouped together, enabling accurate frequency analysis even with undersampled data and preventing artifacts in the reconstructed images.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent changes the parameter of data ordering in k-space. Instead of using the conventional sequential ordering of phase-encoding lines, the invention reorders the data so that the center portion starts from a predetermined line. This parameter change in data organization allows the reconstruction algorithm to correctly interpret frequency information from undersampled data, maintaining image quality while enabling faster imaging through reduced sampling.

Inventive Principle:

Principle #35Parameter changes

2Ease of operation

If k-space data is acquired in conventional order, then ease of operation is maintained, but manufacturing precision deteriorates due to discontinuities in signal intensity during reconstruction

Engineering Contradiction:

Improvedata acquisition simplicityVSAvoidsignal intensity continuity

Core Design Contradiction:

Ease of operationVSManufacturing precision

Solution Approach 1:

The patent applies preliminary action by reordering k-space data along the phase-encoding direction before performing the Fourier transform reconstruction. Specifically, the center portion of k-space data (which contains low-frequency signal components) is positioned to start from a predetermined line (e.g., zeroth or first line) rather than following the conventional sequential order. This preliminary reorganization ensures that signal components with similar frequencies are grouped together, enabling accurate frequency analysis even with undersampled data and preventing artifacts in the reconstructed images.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent changes the parameter of data ordering in k-space. Instead of using the conventional sequential ordering of phase-encoding lines, the invention reorders the data so that the center portion starts from a predetermined line. This parameter change in data organization allows the reconstruction algorithm to correctly interpret frequency information from undersampled data, maintaining image quality while enabling faster imaging through reduced sampling.

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 effectively minimizes artifacts and improves image quality by rearranging k-space data for reconstruction, ensuring continuity in signal intensity and reducing the time needed for capturing time-series data, particularly in applications like heart pulsation imaging.

Implementation Method 1

The atoms placed in a magnetic field selectively absorb and emit an electromagnetic wave having a frequency specified by the kind of atoms and magnetic fields

Methodology Applied

Scientific EffectMagnetic resonance: Resonance

Implementation Method 2

The atoms placed in a magnetic field selectively absorb and emit an electromagnetic wave

Methodology Applied

Scientific EffectMagnetic field effect: Magnetic Field

Data Source

PatentUS11016154B2Magnetic resonance imaging apparatus and image reconstruction program

Publication Date: 2021.05.25 CANON MEDICAL SYST CORP

AI summary

A magnetic resonance imaging apparatus according to an embodiment includes a processor. The processor acquires a plurality of pieces of k-space data with undersampling in at least one of axes of k-space and in a certain axis different from the axes of k-space. The processor rearranges the pieces of k-space data into a second order different from a first order in which the pieces of k-space data are acquired. The processor performs a reconstruction process on a rearranged k-space data group to generate an image group.