MRI Flow-Sensitive Gradient Pulse Compensation
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Solution Overview
Problem
Magnetic resonance imaging (MRI) systems face challenges in accurately compensating for fluid flow, such as blood or cerebrospinal fluid flow, which can affect spatial encoding of MR signals, necessitating a precise method to determine and adjust gradient pulse parameters.
Innovation Solution
A system and method that determine an imaging gradient parameter based on a scanning protocol, calculate a time origin for gradient moment calculation, and adjust parameters for a flow-sensitive gradient block to compensate for fluid flow, including determining amplitude and duration values for flow-sensitive gradients to achieve target zeroth-order and first-order gradient moments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If gradient pulse parameters are adjusted to compensate for fluid flow, then spatial encoding accuracy is improved, but system complexity increases
Solution Approach 1:
The system performs preliminary calculation of gradient moment parameters (M0, M1, M2) and determines optimal flow compensation gradient pulse parameters before the actual MRI scanning. This pre-calculation approach allows the system to prepare compensation parameters in advance based on the specific imaging sequence and scan protocol, reducing real-time computational complexity while maintaining high spatial encoding accuracy.
Solution Approach 2:
The patent introduces an intermediary computational module that acts as a bridge between the imaging sequence definition and the gradient pulse generation. This module calculates the required gradient moment parameters and generates appropriate compensation gradients, effectively mediating between the imaging requirements and the physical gradient hardware, thereby simplifying the overall system architecture.
2Manufacturing precision
If flow sensitive gradient block parameters are precisely determined, then image fidelity is improved, but calculation time increases
Solution Approach 1:
The system performs preliminary calculation of gradient moment parameters (M0, M1, M2) and determines optimal flow compensation gradient pulse parameters before the actual MRI scanning. This pre-calculation approach allows the system to prepare compensation parameters in advance based on the specific imaging sequence and scan protocol, reducing real-time computational complexity while maintaining high spatial encoding accuracy.
Solution Approach 2:
The patent transforms the complex problem of flow compensation into a parameter optimization problem by defining specific gradient moment parameters (M0, M1, M2) as target values. The system then adjusts gradient pulse parameters (amplitude, duration, timing) to achieve these target moments, converting a complex image quality optimization into a more tractable parameter matching problem that can be solved efficiently.
Data Source
AI summary
A method for determining a flow sensitive gradient block includes determine a gradient parameter for one or more echoes in an imaging sequence according to a scanning protocol. The method also includes determining one or more time origins for gradient moment calculation based on the gradient parameter and obtaining one or more target zeroth-order gradient moments and one or more target first-order gradient moments corresponding to the one or more time origins. The method further includes determining one or more parameters of the one or more flow sensitive gradient blocks with respect to the one or more target zeroth-order gradient moments and the one or more target first-order gradient moment and updating the gradient parameter according to the one or more parameters of the one or more flow sensitive gradient blocks.