MRI Slice Leakage Detection via SENSE Reconstruction
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Solution Overview
Problem
Current MRI techniques, such as Simultaneous Multi-Slice (SMS) and Sensitivity Encoding (SENSE), face challenges in accurately identifying and removing inter-slice leakage artifacts, which can lead to misinterpretation of image data and reduced image quality due to inaccuracies in coil sensitivity maps.
Innovation Solution
An image domain parallel imaging technique is developed to spatially identify and measure inter-slice leakage by using SENSE reconstruction to separate slice images and generate slice leakage maps, allowing for the detection of artifacts and improved image reconstruction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If Simultaneous Multi-Slice (SMS) and Sensitivity Encoding (SENSE) techniques are used for accelerated MRI imaging, then imaging speed and productivity are improved, but inter-slice leakage artifacts occur and image quality deteriorates
Solution Approach 1:
The patent segments the imaging process into two distinct phases: a calibration scan phase where slice leakage is measured and characterized, and a subsequent imaging phase where the pre-measured leakage information is used to correct artifacts. This segmentation allows the system to maintain high imaging speed while separately addressing quality issues through pre-acquired calibration data.
Solution Approach 2:
The patent performs preliminary calibration scans before actual imaging to measure and store slice leakage characteristics. These pre-acquired leakage maps are then applied during subsequent imaging sessions to correct artifacts, eliminating the need for real-time leakage measurement and maintaining imaging speed while improving quality.
2Difficulty of detecting and measuring
If SENSE reconstruction is used to separate slice images, then slice leakage identification capability is improved, but measurement accuracy deteriorates due to inaccuracies in coil sensitivity maps
Solution Approach 1:
The patent introduces an intermediary calibration process that uses a simplified single-slice imaging model to measure slice leakage independently of the complex multi-slice reconstruction. This intermediary measurement step creates accurate leakage maps that can then be applied to improve the accuracy of subsequent SENSE reconstructions without being affected by coil sensitivity map inaccuracies.
Solution Approach 2:
The calibration process uses the imaging system itself to measure its own slice leakage characteristics by acquiring calibration data and processing it through the reconstruction algorithm. This self-measurement approach ensures that the leakage characterization is specific to the actual system being used, improving measurement accuracy.
3Difficulty of detecting and measuring
If spatial identification and measurement of inter-slice leakage is implemented, then artifact detection capability is improved, but device complexity increases
Solution Approach 1:
The patent creates simplified copies or models of the slice leakage phenomenon through calibration scans. These leakage maps serve as representative models that capture the essential leakage characteristics without requiring complex real-time analysis during imaging, thereby improving artifact detection while minimizing additional system complexity.
Data Source
AI summary
Magnetic resonance imaging (MRI) systems and methods determine slice leakage and/or residual aliasing in the image domain in accelerated MRI imaging. Implementations process one slice of MRI image domain data by input to a sensitivity encoding (SENSE) un-aliasing matrix built from predetermined RF signal reception sensitivity maps, thereby producing as matrix output SENSE-decoded MRI image domain data for one pass through image slice and at least one extra slice, and determine inter-slice leakage and/or in-plane residual aliasing based on content of the at least one extra output slice from the SENSE-decoded MRI image domain data.