Multi-Echo MR Gradient Pulse Parameter Optimization
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Solution Overview
Problem
Conventional multi-echo magnetic resonance (MR) measurement sequences are limited by the maximum gradient pulse amplitude and rate-of-change, restricting spatial resolution and extending measurement duration, which can lead to breathing artifacts and errors due to magnetic field drifts.
Innovation Solution
A method that determines a ratio between the time difference between successive gradient echoes and the quotient of maximum gradient pulse amplitude and rate-of-change to select readout and flyback gradient pulse parameters, ensuring increased spatial resolution without exceeding these limits, using trapezoidal readout pulses and flyback gradients to optimize gradient shape and phase compensation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional multi-echo measurement sequences are used with maximum gradient pulse amplitude and rate-of-change, then spatial resolution is improved, but measurement duration is extended leading to breathing artifacts and magnetic field drift errors
Solution Approach 1:
The patent optimizes gradient pulse parameters (amplitude, duration, timing) to achieve high spatial resolution while maintaining measurement duration within acceptable limits. By carefully adjusting the gradient pulse sequence parameters, the method resolves the contradiction between achieving high resolution and avoiding artifacts from prolonged measurement time
Solution Approach 2:
The patent employs dynamic gradient pulse sequences with variable amplitude and timing parameters adapted to the specific measurement requirements. The gradient pulses are dynamically adjusted to maximize resolution while minimizing total measurement time, thereby reducing breathing artifacts and magnetic field drift effects
2Loss of time
If the time difference between successive gradient echoes is reduced to improve temporal sampling, then measurement duration is shortened, but spatial resolution is limited by maximum gradient pulse constraints
Solution Approach 1:
The patent applies pre-phasing gradient pulses before the readout gradients to pre-compensate for phase accumulation. This preliminary action allows for optimized timing of the readout gradients, enabling shorter time differences between echoes while maintaining sufficient spatial resolution through proper gradient moment management
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
This approach allows for higher spatial resolution in MR images while maintaining compliance with maximum gradient pulse constraints, reducing measurement duration and minimizing errors from magnetic field drifts, thereby improving image quality and analysis accuracy.
Implementation Method 1
at least two gradient echoes are formed sequentially with a predetermined time difference between successive gradient echoes
Implementation Method 2
application of a pre-phasing gradient pulse
Implementation Method 3
a number n of MR echoes is respectively detected in each of separated repetition intervals (TR intervals) after an RF excitation pulse
Data Source
AI summary
In a multi-echo measurement sequence with the goal of optimizing the spatial resolution given predetermined time difference between successive gradient echoes, gradient pulse parameters are set depending on a defined ratio between a predetermined time difference between echo times and a quotient of a predetermined maximum gradient pulse amplitude and a predetermined maximum gradient pulse rate-of-change.