MRI Gradient Pulse Adjustment for PNS-Limited Scan Sequences
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Solution Overview
Problem
Current MRI systems reduce the slew rate to mitigate peripheral nerve stimulation (PNS), leading to increased minimum repetition time (minTR) and echo spacing (ESP), thereby compromising system performance.
Innovation Solution
Adjust the scanning sequence by maintaining the slew rate and reducing the amplitude of gradient pulses in segments where PNS scores exceed a threshold, allowing higher slew rates without stimulating nerves.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the overall slew rate of the scanning sequence is reduced to reduce peripheral nerve stimulation, then peripheral nerve stimulation is reduced, but the minimum repetition time and echo spacing increase significantly, thereby reducing MRI system performance
Solution Approach 1:
The scanning sequence is divided into multiple segments based on their PNS scores. Segments with high PNS scores are identified and processed separately from segments with low PNS scores. This allows different slew rate settings to be applied to different segments, rather than uniformly reducing the slew rate for the entire sequence, thereby maintaining system performance while reducing PNS.
Solution Approach 2:
Different slew rate settings are applied to different segments of the scanning sequence based on their specific PNS characteristics. High-PNS segments receive reduced slew rates to minimize nerve stimulation, while low-PNS segments maintain higher slew rates to preserve imaging performance. This localized approach resolves the contradiction between PNS reduction and performance maintenance.
2Object-affected harmful factors
If the slew rate is reduced to mitigate peripheral nerve stimulation, then peripheral nerve stimulation is reduced, but the scanning time increases due to increased minimum repetition time
Solution Approach 1:
The scanning sequence is segmented into high-PNS and low-PNS portions, allowing independent optimization of each. This segmentation enables the system to minimize scanning time in low-PNS segments while controlling PNS in high-PNS segments, overall reducing scanning time compared to uniform slew rate reduction.
Solution Approach 2:
The slew rate is dynamically adjusted based on the segment type rather than using a fixed reduced slew rate for the entire sequence. The system transitions between different slew rate settings depending on the segment characteristics, optimizing the balance between PNS reduction and scanning time efficiency.
Data Source
AI summary
A magnetic resonance imaging system, and a magnetic resonance imaging method are provided. The method includes: acquiring a scanning sequence for a magnetic resonance imaging system, the scanning sequence including a gradient pulse; and determining a first-type segment of the scanning sequence, in which a peripheral nerve stimulation score exceeds a threshold, maintaining a slew rate of a gradient pulse of the first-type segment, and reducing an absolute value of an amplitude of the gradient pulse of the first-type segment.