MRI Phase Correction for Seamless MRA Reconstruction
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Solution Overview
Problem
Magnetic resonance angiography (MRA) with continuous table motion experiences artifacts due to signal falloff at sub-field of view (FOV) boundaries, caused by phase differences between abutting FOVs, leading to image discontinuities and lost data acquisition time.
Innovation Solution
Measuring and correcting volume phase shifts along the direction of table motion by calculating the phase of the central k-space view and applying these corrections to subsequent views before image reconstruction, allowing for real-time phase correction during scanning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If continuous table motion is used to acquire MRI data from extended field of view, then imaging coverage is improved, but artifacts appear at sub-FOV boundaries due to phase discontinuities
Solution Approach 1:
The patent applies feedback by continuously monitoring the phase of the central k-space view during table motion and using this information to dynamically correct phase discontinuities in real-time. The phase measurement from the central view serves as feedback to adjust and compensate for artifacts at FOV boundaries, enabling seamless image reconstruction across extended fields of view.
Solution Approach 2:
The patent uses the central k-space view as an intermediary element to measure phase shifts caused by table motion. This central view acts as a mediator that captures the phase information needed to correct discontinuities in the hybrid space data, allowing the system to compensate for artifacts without disrupting the continuous scanning process.
2Area of stationary object
If multiple separate images are acquired at different table stations, then extended field of view coverage is achieved, but image discontinuities occur at boundaries due to different brightness and contrast
Solution Approach 1:
The patent merges multiple FOV datasets into a single continuous image by using phase correction to ensure seamless transitions at boundaries. Instead of acquiring separate images and manually registering them, the system combines hybrid space data from continuous table motion while maintaining phase consistency, resulting in a unified image with uniform brightness and contrast across the entire extended field of view.
Solution Approach 2:
The patent changes the phase parameter of the image data to eliminate discontinuities at FOV boundaries. By measuring and correcting phase shifts in the hybrid space data, the system adjusts the phase parameter to ensure continuous and uniform image appearance across stitched regions, eliminating the brightness and contrast mismatches that would otherwise occur.
3Area of stationary object
If table is moved between stations to acquire multiple images, then extended field of view is covered, but valuable time is lost during table movement and magnetization equilibrium
Solution Approach 1:
The patent maintains continuous table motion throughout the entire scanning process, eliminating the need to stop and reposition the table between acquisitions. By continuously acquiring data as the table moves through the extended field of view, the system ensures that the table is always in motion during useful acquisition time, maximizing data collection efficiency and minimizing idle time.
Solution Approach 2:
The patent performs phase correction calculations in advance based on the central k-space view measurements, preparing correction factors before they are needed during the continuous scanning process. This preliminary action allows the system to maintain continuous table motion while pre-computing the necessary phase adjustments, ensuring that no time is lost during the actual data acquisition.
4Manufacturing precision
If phase correction is performed in real-time during scanning, then image quality is improved, but processing complexity increases
Solution Approach 1:
The patent performs phase correction calculations in advance by first measuring the phase of the central k-space view and then using this information to pre-compute correction factors for subsequent data acquisition. This preliminary action allows the system to maintain real-time image quality without requiring complex processing during the actual scanning, as the phase correction parameters are already prepared and can be applied efficiently during continuous table motion.
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
Substantially eliminates phase discontinuities and artifacts at FOV boundaries, ensuring seamless image reconstruction and maintaining data acquisition pace with the moving contrast bolus.
Implementation Method 1
measuring the phase shifts that occur along the direction of table motion and correcting the phase of image data acquired from the volume
Implementation Method 2
correcting the phase of image data acquired from the volume prior to image reconstruction
Data Source
AI summary
MRA data is acquired from a large, longitudinal region of interest by translating the patient through the more limited longitudinal FOV of the MRI system as a three-dimensional MRA data set are acquired. Patient table movement is controlled to track a bolus of contrast agent as it passes through the region of interest. A seamless image of the entire region of interest is reconstructed after correcting the phase of acquired MRA data to reduce the signal falloff at abutting longitudinal FOVs. Phase corrections are determined from the central DC views acquired during the scan.