MRI Coil Sensitivity Map Correction for Image Uniformity
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Solution Overview
Problem
Current MRI reconstruction methods assume a uniform quadrature body coil image, but in practice, this image can be non-uniform due to factors like non-uniform radio frequency transmitting and receiving fields, leading to non-uniform coil sensitivity maps and suboptimal image reconstruction.
Innovation Solution
The method involves determining array coil images and a quadrature body coil image during a prescan, correcting the uniformity of the quadrature body coil image using techniques like threshold segmentation and extrapolation, and then using the corrected image to calculate coil sensitivity maps for improved magnetic resonance image reconstruction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a uniform quadrature body coil image is assumed for reconstruction, then the reconstruction process is simplified, but the coil sensitivity maps become non-uniform and image quality deteriorates
Solution Approach 1:
The patent applies preliminary action by performing uniformity correction on the quadrature body coil image before using it to calculate coil sensitivity maps. The correction process includes identifying non-uniform regions and applying compensation algorithms to create a uniformly corrected reference image, which is then used in the sensitivity map calculation to ensure accurate and uniform results.
2Manufacturing precision
If the quadrature body coil image is corrected for uniformity, then coil sensitivity map uniformity improves, but calculation requirements and processing time increase
Solution Approach 1:
The patent applies partial action by selectively correcting only the non-uniform regions of the quadrature body coil image rather than processing the entire image uniformly. The method identifies specific areas with uniformity deviations and applies correction algorithms only to those regions, reducing overall calculation requirements while maintaining the uniformity improvement benefits.
3Reliability
If non-uniform radio frequency fields are present, then signal reception occurs, but the resulting images exhibit non-uniformity and reduced quality
Solution Approach 1:
The patent converts the harmful non-uniformity caused by non-uniform radio frequency fields into a beneficial correction opportunity. By deliberately measuring and characterizing the non-uniform quadrature body coil image, the system creates a correction map that, when applied, compensates for the original non-uniformity. This transforms the harmful RF field non-uniformity into useful correction data that improves final image uniformity.
Data Source
AI summary
Methods, devices and apparatus for reconstructing a magnetic resonance image are provided. In one aspect, a method includes: determining array coil images according to first data collected by array coils of an MRI device during a prescan, where each coil of the array coils corresponds to a respective one of channels; determining a quadrature body coil image according to at least one of second data collected by a quadrature body coil of the MRI device during the prescan and the first data collected by the array coils; obtaining a corrected quadrature body coil image by correcting an uniformity of the quadrature body coil image; determining coil sensitivity maps according to the array coil images and the corrected quadrature body coil image; and reconstructing a magnetic resonance image with third data collected by the array coils during a normal scan according to the coil sensitivity maps.