RF Pulse Shaping for MR Scanner Edge Inhomogeneity Compensation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
MR scanners with short patient receiving tunnels experience reduced homogeneity of the basic magnetic field and gradient accuracy, leading to artifacts such as compressed regions and increased signal intensity at the edges, which are not effectively addressed by existing methods that require doubling the scanning time to average MR signals.
Innovation Solution
The method involves controlling an MR data acquisition scanner to execute an imaging sequence with RF pulses that enhance magnetization in regions with higher homogeneity and reduce magnetization in regions with lower homogeneity, using a system matrix equation to optimize RF pulses and minimize artifacts without increasing scanning time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If MR signals are recorded multiple times and averaged to eliminate artifacts, then image quality is improved, but scanning time is at least doubled
Solution Approach 1:
The patent applies local quality by differentiating between two recording regions: a first recording region with high homogeneity (good image quality) and a second recording region with low homogeneity (artifacts). Instead of uniformly processing all data, the method selectively handles each region differently, using the high-quality central region to compensate for artifacts in the edge region, thereby eliminating artifacts without requiring multiple full scans.
Solution Approach 2:
The patent uses preliminary action by acquiring reference data or calibration data in advance during the same scan. This reference data from the high homogeneity region is used to correct artifacts in the low homogeneity region before final image reconstruction, allowing single-scan artifact elimination without requiring separate calibration scans or signal averaging.
2Length of stationary object
If the patient receiving tunnel is shortened, then device compactness is improved, but homogeneity of the basic magnetic field and gradient accuracy deteriorate
Solution Approach 1:
The patent recognizes that different regions of the patient receiving tunnel have different homogeneity characteristics. It divides the tunnel into a first recording region (central, high homogeneity) and a second recording region (edge, low homogeneity). By treating these regions differently in data processing and using the high homogeneity region to correct the low homogeneity region, the patent enables shorter tunnel designs while maintaining overall image quality.
Solution Approach 2:
The patent uses an intermediary approach by introducing reference data or calibration data from the high homogeneity region as a mediator to correct artifacts in the low homogeneity region. This intermediary data allows the system to compensate for the reduced homogeneity caused by shorter tunnel length, enabling compact scanner design without sacrificing image quality.
3Productivity
If parallel imaging technique is used, then scanning efficiency is improved, but artifacts occur at edge regions due to incorrect spatial encoding
Solution Approach 1:
The patent applies local quality by identifying that parallel imaging artifacts occur specifically in the second recording region (edge region) where homogeneity is low. The method selectively corrects this region using reference data from the first recording region (central region), preserving the scanning efficiency benefits of parallel imaging while eliminating artifacts only where they occur, rather than requiring universal correction across the entire image.
Solution Approach 2:
The patent uses reference data or calibration data as an intermediary to correct the spatial encoding errors that occur in parallel imaging. This intermediary data, acquired from the high homogeneity region, allows the system to compensate for the incorrect spatial encoding in the edge region, maintaining both the efficiency of parallel imaging and the accuracy of spatial representation.
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 reduces high signal intensities and artifacts at the edges of MR system components, improving image quality by controlling magnetization and minimizing incorrect spatial encoding, while maintaining efficient scanning times.
Implementation Method 1
Magnetization of nuclear spins in the recording volume is excited with at least one RF pulse radiated by an RF radiator of the scanner
Data Source
AI summary
In a method and magnetic resonance (MR) apparatus for recording MR signals in a recording volume of an examination object with an imaging sequence, the recording volume has a first recording region in which at least one system component of the scanner of the MR apparatus has a first homogeneity, which is greater than a homogeneity of the at least one scanner component in a second recording region of the recording volume. A magnetization of nuclear spins in the recording volume is produced by at least one RF pulse, with the RF pulse being determined such that the magnetization produced in the first recording region by the at least one RF pulse is greater than magnetization produced in the second recording region by the at least one RF pulse.