Gradient Pulse Optimization for MR Noise Reduction
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Solution Overview
Problem
High rise rates in magnetic resonance (MR) gradient pulses lead to noise, energy inefficiency, and hardware stress, causing distortions and helium boil-off in MR scanners.
Innovation Solution
Optimizing the pulse sequence by subdividing modifiable time intervals into zero-moment and moment subintervals, allowing for gradient pulse modification while maintaining the desired gradient moment, reducing noise and energy consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If high rise rates are used in gradient pulses, then the time stipulations within pulse sequence are met, but noise level increases and energy usage increases
Solution Approach 1:
The gradient pulse is segmented into multiple smaller pulses with different amplitudes and durations. Instead of applying a single high-amplitude gradient pulse, the invention uses a train of lower-amplitude gradient pulses that collectively achieve the same gradient moment while reducing peak noise and energy consumption.
Solution Approach 2:
The invention employs periodic gradient pulses with optimized timing and amplitude patterns. By using periodic action with varying amplitudes rather than continuous high-amplitude gradients, the patent reduces noise and energy usage while maintaining the required gradient moment for spatial encoding.
2Speed
If high rise rates are used in gradient pulses, then the time stipulations within pulse sequence are met, but energy usage increases
Solution Approach 1:
The gradient pulse is segmented into multiple smaller pulses with different amplitudes and durations. Instead of applying a single high-amplitude gradient pulse, the invention uses a train of lower-amplitude gradient pulses that collectively achieve the same gradient moment while reducing peak noise and energy consumption.
Solution Approach 2:
The invention changes the parameters of gradient pulses (amplitude, duration, timing) to optimize energy efficiency. By adjusting these parameters within the modifiable time intervals, the system achieves the required gradient moment with lower energy consumption while maintaining imaging performance.
3Speed
If high rise rates are used in gradient pulses, then the time stipulations within pulse sequence are met, but gradient coils and hardware are heavily loaded
Solution Approach 1:
The gradient pulse is segmented into multiple smaller pulses with different amplitudes and durations. Instead of applying a single high-amplitude gradient pulse, the invention uses a train of lower-amplitude gradient pulses that collectively achieve the same gradient moment while reducing peak noise and energy consumption.
Solution Approach 2:
The invention applies gradient pulses with optimized amplitude profiles that prevent excessive loading on gradient coils. By using lower-amplitude pulses with appropriate timing, the system cushions against hardware stress and distortion while maintaining the required gradient moment for spatial encoding.
4Speed
If rapidly changing magnetic field gradients are used, then time stipulations are met, but distortions and oscillations in gradient coils occur
Solution Approach 1:
The gradient pulse is segmented into multiple smaller pulses with different amplitudes and durations. Instead of applying a single high-amplitude gradient pulse, the invention uses a train of lower-amplitude gradient pulses that collectively achieve the same gradient moment while reducing peak noise and energy consumption.
Solution Approach 2:
The invention applies gradient pulses with optimized amplitude profiles that prevent excessive loading on gradient coils. By using lower-amplitude pulses with appropriate timing, the system cushions against hardware stress and distortion while maintaining the required gradient moment for spatial encoding.
5Object-generated harmful factors
If gradient pulses are optimized to reduce noise, then noise level decreases, but time span of pulse sequence increases
Solution Approach 1:
The invention employs periodic gradient pulses with optimized timing and amplitude patterns. By using periodic action with varying amplitudes rather than continuous high-amplitude gradients, the patent reduces noise and energy usage while maintaining the required gradient moment for spatial encoding.
Solution Approach 2:
The invention changes the parameters of gradient pulses (amplitude, duration, timing) to optimize noise reduction while maintaining acceptable scan times. By adjusting these parameters within the modifiable time intervals, the system achieves lower noise levels without excessive time penalty.
Data Source
AI summary
In a method magnetic resonance apparatus, a pulse sequence is optimized in order to identify a time interval of the pulse sequence during which gradient pulses are modifiable, and subdividing that time interval into two time subintervals wherein, during one of these two time subintervals, no gradient pulse is activated. Such an optimized pulse sequence can be repeated in a number of repetitions, during which magnetic resonance data are acquired, with a contiguous gradient being activated between repetitions, that performs the role of a conventional spoiler occurring directly before an RF excitation the contiguous gradient occurs during a duration that is shorter than a time directly following acquisition of data in one repetition and before excitation in the next repetition.