3D Radial MR Imaging With Soft Motion Gating
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Solution Overview
Problem
Current 3D and 4D radial or spiral MR imaging techniques suffer from motion-induced signal fluctuations, leading to compromised image quality despite their intrinsic motion-robustness.
Innovation Solution
A method involving oversampling of the central portion of k-space in a 3D radial or spiral acquisition scheme, combined with motion detection and soft gating, where MR signals from more frequent motion states are weighted more heavily than those from less frequent states, reducing artifacts and maintaining minimal scan time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If 3D radial or spiral acquisition is used, then motion robustness is improved, but motion-induced signal fluctuations still occur leading to compromised image quality
Solution Approach 1:
The patent applies different weighting factors to different regions of k-space, specifically applying stronger motion correction weighting to the central portion of k-space where motion-induced signal fluctuations have the most impact on image quality. This local differentiation allows the system to maintain motion robustness while selectively correcting the most problematic regions.
Solution Approach 2:
The patent changes the weighting parameter across different regions of k-space, applying stronger weighting factors to the central portion and weaker weighting factors to peripheral portions. This parameter variation allows the system to address motion-induced signal fluctuations in the most critical regions while preserving overall image quality and maintaining efficient scan times.
2Manufacturing precision
If motion correction weighting is applied to central k-space, then motion artifacts are reduced, but scan time may increase
Solution Approach 1:
The patent applies motion correction weighting selectively to the central portion of k-space rather than uniformly across all k-space data. This localized approach concentrates computational resources on the regions that most impact image quality while minimizing additional processing time, thereby reducing motion artifacts without significantly increasing scan time.
Solution Approach 2:
The patent applies partial motion correction by using a range of weighting factors from strong to weak across different k-space regions. This partial action approach corrects the most critical motion-induced signal fluctuations in the central k-space while accepting some residual artifacts in peripheral regions, achieving a balance between image quality improvement and scan time efficiency.
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 significantly reduces motion artifacts in MR images while maintaining efficient scan times, providing improved image quality compared to conventional methods.
Implementation Method 1
a main magnet coil for generating a uniform, steady magnetic field B0 within an examination volume
Implementation Method 2
a number of gradient coils for generating time-varying magnetic field gradients along different spatial directions within the examination volume
Implementation Method 3
at least one body RF coil for generating RF pulses within the examination volume and/or for receiving MR signals from a body of a patient positioned in the examination volume
Data Source
Figure 1
Figure 2a~3
Figure 4a~4b
AI summary
The invention relates to a method of MR imaging of an object (10). It is an object of the invention to enable MR imaging using a 3D radial or spiral acquisition scheme providing an enhanced image quality in the presence of motion. The method comprises the steps of: - generating MR signals by subjecting the object (10) to an imaging sequence comprising RF pulses and switched magnetic field gradients; - acquiring the MR signals using a 3D radial or spiral acquisition scheme with oversampling of a central portion (26) of k-space; - detecting motion-induced displacements (d) and/or deformations of the object (10) during the acquisition of the MR signals and assigning each of the acquired MR signals to a motion state; - reconstructing an MR image from the MR signals weighted in the central portion (26) of k-space, wherein a stronger weighting (W, 30) is applied to MR signals acquired in more frequent motion states, while a weaker weighting (W, 31, 32) is applied to MR signals acquired in less frequent motion states. Moreover, the invention relates to a MR device (1) and to a computer program for a MR device (1).