MR Phantom with Granular Structure for Local Image Sharpness Assessment
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Solution Overview
Problem
Conventional MR imaging phantoms lack the ability to assess image sharpness in different regions, which is crucial for evaluating the quality of spiral imaging sequences, as they are unstructured and do not provide adequate areas for evaluating image sharpness.
Innovation Solution
A phantom with a structured volume filled with granules of solid material surrounded by liquid is used, allowing for the acquisition of MR signals and reconstruction of images to derive a measure of local image sharpness in multiple regions, specifically designed to assess image quality and sensitivity to off-resonance effects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional unstructured phantoms are used, then the phantom is simple to manufacture, but the image sharpness cannot be assessed in different regions
Solution Approach 1:
The phantom incorporates multiple regions with different granule densities and sizes, creating local variations in image sharpness characteristics. Each region serves as a specific test case for evaluating imaging performance under different conditions, enabling localized assessment of sharpness while maintaining an otherwise simple phantom structure.
Solution Approach 2:
The phantom volume is divided into multiple distinct regions, each containing granules with specific characteristics (different densities, sizes, or distributions). This segmentation allows the phantom to provide multiple assessment targets within a single structure, enabling comprehensive sharpness evaluation without requiring multiple separate phantoms.
2Productivity
If spiral imaging sequences are used, then the imaging efficiency is improved, but the image quality is degraded due to sensitivity to off-resonance effects
Solution Approach 1:
The phantom acts as an intermediary testing device that bridges the gap between spiral imaging efficiency and image quality requirements. By providing known reference structures with controlled granule distributions, the phantom enables quantitative assessment of how off-resonance effects impact sharpness, allowing for calibration and quality control of spiral imaging sequences.
Solution Approach 2:
The phantom provides measurable reference data that feeds back into the imaging process. By comparing the actual MR signal characteristics from the phantom regions against expected values, the system can identify and correct off-resonance effects, thereby maintaining image quality while preserving the efficiency benefits of spiral imaging.
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
Enables simple, practical, and fast assessment of image sharpness across the entire phantom volume, effectively evaluating the quality of MR imaging sequences and spatial magnetic field distribution, particularly beneficial for spiral imaging sequences.
Implementation Method 1
Image-forming MR methods which utilize the interaction between magnetic fields and nuclear spins in order to form two-dimensional or three-dimensional images
Implementation Method 2
The variation of the magnetization can be detected by means of receiving RF coils which are arranged and oriented within an examination volume of the MR device in such a manner that the variation of the magnetization is measured in the direction perpendicular to the z-axis
Data Source
AI summary
A method of magnetic resonance (MR) imaging includes a phantom that is inexpensive to produce and enables simple, practical and fast assessment of image sharpness, in particular for checking image quality of MR imaging with spiral acquisition. The method includes subjecting a phantom, which comprises a volume filled with a bulk of granules of solid material surrounded by a liquid, to an imaging sequence, acquiring MR signals from the phantom, reconstructing an MR image from the acquired MR signals, and deriving a measure of the local image sharpness in two or more different image regions from the MR image, wherein each image region is a representation of a part of the phantom volume.