MRI Gradient Pulse Timing for Shorter TR and Motion-Robust Scans
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Solution Overview
Problem
Existing magnetic resonance imaging systems face challenges in achieving a short repetition time (TR) and high time resolution while minimizing the impact of subject motion, particularly in oblique scanning scenarios.
Innovation Solution
Adjusting the waveform of the first gradient pulse within a signal acquisition time window to include parts of the gradient rise and fall times, allowing for slope sampling and reducing the repetition time (TR) of the scan sequence, thereby improving image quality and resolution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If the gradient pulse waveform is adjusted to include gradient rise and fall times in the signal acquisition time window, then the repetition time (TR) is reduced and time resolution is improved, but the gradient pulse waveform complexity increases
Solution Approach 1:
The gradient pulse waveform is dynamically adjusted by including the gradient rise and fall times within the signal acquisition time window. This dynamic timing adjustment allows the system to capture signals during the previously excluded transition periods, effectively reducing the repetition time (TR) without requiring additional hardware complexity.
Solution Approach 2:
The invention changes the temporal parameters of the gradient pulse waveform by redefining the signal acquisition time window to overlap with the gradient rise and fall times. This parameter modification enables more efficient use of the available time window, reducing TR while maintaining signal quality through appropriate waveform design.
2Measurement precision
If the signal acquisition time window includes gradient rise and fall times, then time resolution is improved, but the difficulty of detecting and measuring signals increases
Solution Approach 1:
The system employs feedback mechanisms to monitor and adjust the gradient pulse timing and amplitude during the rise and fall phases. This feedback control ensures that signals acquired during the gradient transitions are properly calibrated and corrected, maintaining measurement precision while managing the increased detection complexity through active compensation.
Solution Approach 2:
The gradient pulse waveform is pre-calculated and pre-adjusted to optimize signal acquisition during the rise and fall times. By performing preliminary waveform design and timing optimization, the system prepares the optimal acquisition parameters in advance, reducing the real-time detection difficulty while achieving high time resolution.
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
The adjusted waveform technique reduces TR, enhances time resolution, and minimizes the effect of subject motion during imaging, resulting in improved diagnostic quality.
Implementation Method 1
a gradient amplifier, a radio-frequency (RF) amplifier, a gradient coil
Implementation Method 2
The transmit/receive coil generates a radio-frequency excitation signal to excite a scan subject to generate a magnetic resonance signal
Implementation Method 3
Magnetic resonance systems generally have a main magnet
Data Source
AI summary
A magnetic resonance imaging method and a magnetic resonance imaging system is provided. The method includes: adjusting a waveform of a gradient pulse in a scan sequence according to a signal acquisition time window, wherein the signal acquisition time window at least includes at least part of the gradient rise and gradient fall times of the gradient pulse; and generating and transmitting a scan sequence with an adjusted waveform, acquiring a magnetic resonance signal in the signal acquisition time window, and reconstructing a magnetic resonance image according to the magnetic resonance signal.