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Quantifying the Relative Thickness of Conductive Ferromagnetic Materials Using Detector Coil-Based Pulsed Eddy Current Sensors
Published on: January 16, 2020
Parallel transmission RF pulse design for eddy current correction at ultra high field
Hai Zheng1, Tiejun Zhao, Yongxian Qian
1Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, USA.
Journal of Magnetic Resonance (San Diego, Calif. : 1997)
|July 14, 2012
Summary
Eddy current fields in parallel transmission MRI can distort radiofrequency (RF) excitation patterns. This study introduces a novel RF pulse design to correct these distortions, improving image quality and efficiency in accelerated MRI.
Area of Science:
- Magnetic Resonance Imaging (MRI)
- Radiofrequency (RF) Pulse Design
- Parallel Transmission Technology
Background:
- Multidimensional spatially selective RF pulses are crucial for mitigating B₁ and B₀ inhomogeneities in MRI.
- Long RF pulse durations limit the practical application of these techniques.
- Parallel transmission offers a way to shorten RF pulse durations without compromising excitation pattern quality.
Purpose of the Study:
- To investigate the impact of eddy current fields on excitation patterns in accelerated parallel transmission MRI.
- To develop and validate an RF pulse design method for correcting eddy current effects.
- To compare the proposed correction method with existing techniques in terms of performance and efficiency.
Main Methods:
- Analysis of eddy current field effects on MRI excitation patterns.
- Design of a model-based RF pulse sequence incorporating eddy current correction.
- Experimental validation on a 7 Tesla (T) human eight-channel parallel transmit system.
Main Results:
- Eddy current fields were shown to negatively affect excitation patterns.
- The proposed RF pulse design method effectively corrected eddy current-induced distortions.
- Experimental results demonstrated substantial improvements in excitation pattern quality.
- The model-based correction achieved comparable results to the trajectory measurement method but with significantly improved time efficiency.
Conclusions:
- Eddy current correction is essential for high-quality accelerated parallel transmission MRI.
- The developed model-based RF pulse design offers an efficient and effective solution for eddy current compensation.
- This method enhances the practical utility of parallel transmission in advanced MRI applications.
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